CHANGELOG.md

# 4.3

## C

- **Additions**
  - Added generated slider data `max` APIs.
  - Added generated physics constraint `ScaleYMode` APIs.
  - Added generated `Interpolation` and `TrackEntry` mix interpolation APIs for non-linear animation mixing.
  - Added `spine_slider` and `spine_slider_data` types for slider constraints
  - Regenerated C bindings for the AnimationState additive/hold rework and Skin placeholder name rename in spine-cpp.
  - Regenerated C bindings for the updated clipping runtime, including convex and inverse clipping support.
  - Regenerated linked mesh APIs so source meshes can be resolved from different slots, matching spine-cpp.
  - Added generated attachment timeline slot APIs, including `spine_attachment_get_timeline_slots()`, `spine_attachment_set_timeline_slots()`, and `spine_attachment_is_timeline_active()`.
  - Added generated animation color and bone icon size/rotation APIs.

- **Bug fixes**
  - Fixed draw order timelines not mixing out to the setup pose.
  - Fixed slider sorting crashes when slider animations key slot or constraint timelines.
  - Fixed bones that don't inherit rotation when parent scale is near zero.
  - Fixed `BonePose::updateLocalTransform()` for `noScale` and `noScaleOrReflection` inheritance.
  - Fixed `ScaleYMode_Volume` to avoid extreme scaleY values for very small scaleX factors.
  - Fixed attachment timelines so hidden setup-pose attachments remain hidden while mixing out, preserving deform behavior.
  - Fixed `Skeleton::updateWorldTransform()` to avoid copying draw order unless it is constrained.

- **Breaking changes**
  - Removed generated `spine_bone_pose_reset_world()` because resetWorld is an internal implementation detail.
  - Attachment loader APIs now receive both the skin `placeholder` and resolved attachment `name`.
  - `spine_animation_state_get_current()` renamed to `spine_animation_state_get_track()`.
  - Generated mesh attachment APIs now use `source_mesh` naming instead of `parent_mesh` to match spine-cpp, eg `spine_mesh_attachment_get_source_mesh()` / `spine_mesh_attachment_set_source_mesh()`.
  - `spine_track_entry_get_mix_blend()` / `spine_track_entry_set_mix_blend()` removed. Use `spine_track_entry_get_additive()` / `spine_track_entry_set_additive()` instead.
  - `spine_track_entry_get_hold_previous()` / `spine_track_entry_set_hold_previous()` removed.
  - `spine_skin_entry_get_name()` renamed to `spine_skin_entry_get_placeholder_name()`.
  - Timeline `apply()` signature changed: `spine_mix_blend` and `spine_mix_direction` parameters replaced with `bool fromSetup, bool add, bool out`.
  - `spine_animation_apply()` signature changed to match.
  - `spine_curve_timeline1_get_absolute_value()`, `spine_curve_timeline1_get_relative_value()`, `spine_curve_timeline1_get_scale_value()` signatures changed.
  - Added `spine_slider_timeline` and `spine_slider_mix_timeline` for animating sliders
  - Added new pose system with `spine_bone_local`, `spine_bone_pose`, and related types
  - Added `spine_pose`, `spine_posed`, and `spine_posed_active` base types
  - Regenerated the C API for the sequence attachment refactor in spine-cpp. `spine_region_attachment` and `spine_mesh_attachment` now mirror the new non-null `Sequence` model exposed by the C++ runtime.
  - IK constraint data now uses `spine_scale_y` instead of the old `uniform` boolean, matching spine-cpp.
  - `spine_ik_constraint_data_get_scale_y()` / `spine_ik_constraint_data_set_scale_y()` and `spine_scale_y` renamed to `spine_ik_constraint_data_get_scale_y_mode()` / `spine_ik_constraint_data_set_scale_y_mode()` and `spine_scale_y_mode`.

- **Breaking changes**
  - **IMPORTANT**: The C runtime has been completely rewritten as an auto-generated wrapper around the C++ runtime. This is a major breaking change. Users must update their code to use the new API. See https://esotericsoftware.com/spine-c
  - All types, functions, and headers have been restructured
  - The new runtime provides full feature parity with C++ through automatic code generation, has nullability annotations and documentation, and supports lightweight RTTI, allowing language specific wrappers to be built around it that expose the full type hierarchy idiomatically. See spine-ios and spine-flutter for examples.
  - Sequence attachments now follow the spine-cpp sequence refactor. Region and mesh attachments no longer use the old mutable region/UV update path.
  - Bone setup and unconstrained pose APIs now use `spine_bone_pose` instead of `spine_bone_local`. Generated bindings such as `spine_bone_data_get_setup_pose()` and `spine_bone_get_pose()` now return `spine_bone_pose`.
  - Renamed setup pose functions:
    - `spSkeleton_setToSetupPose()` → `spine_skeleton_setup_pose()`
    - `spSkeleton_setBonesToSetupPose()` → `spine_skeleton_setup_pose_bones()`
    - `spSkeleton_setSlotsToSetupPose()` → `spine_skeleton_setup_pose_slots()`
  - `spine_event_data` no longer stores event payload values directly. Use `spine_event_data_get_setup_pose()` and the returned `spine_event` for setup int, float, string, volume, and balance values.
  - `spine_animation_create()` now takes only the animation name. `spine_animation_set_timelines()` now also requires the animation's bone indices.

### SFML

- **Restructuring**
  - Reorganized directory structure - merged with C++ SFML into unified structure

- **Breaking changes**
  - Updated to use new C runtime API

### SDL

- **Additions**
  - Added CMakePresets.json for modern CMake configuration
  - Updated examples with improved rendering

- **Restructuring**
  - Simplified build system with build.sh script

- **Breaking changes**
  - Updated to use new C runtime API
  - `spSkeletonDrawable_update()` now takes additional `spine_physics` parameter

### GLFW

- **Additions**
  - Added CMakePresets.json for modern CMake configuration
  - Added physics example (physics.cpp)
  - Added IK following example (ik-following.cpp)
  - Added dragon sequence examples for binary and JSON loading in both C++ and C:
    - `dragon.cpp`
    - `dragon-json.cpp`
    - `dragon-c.cpp`
    - `dragon-json-c.cpp`
  - Added C mirrors for the physics and IK following examples:
    - `physics-c.cpp`
    - `ik-following-c.cpp`

- **Restructuring**
  - Renamed main-cpp-lite.cpp to main-c.cpp
  - Simplified build system with build.sh script
  - Fixed the GLFW CMake data copy step to copy shared example assets once, avoiding parallel `copy_directory` races under ninja

- **Breaking changes**
  - Updated to use new C runtime API

## C++

- **Additions**
  - Added `SliderData::getMax()` / `setMax()` for nonessential bone-driven slider metadata.
  - Added `PhysicsConstraintData::getScaleYMode()` / `setScaleYMode()` to control how physics scaleX affects scaleY.
  - Added `Interpolation` and `TrackEntry::getMixInterpolation()` / `setMixInterpolation()` for non-linear animation mixing.
  - Added `Slider` and `SliderData` classes for slider constraints
  - Linked meshes can now inherit deform and sequence timelines from source meshes in different slots.
  - Added `Attachment::getTimelineSlots()`, `Attachment::setTimelineSlots()`, and `Attachment::isTimelineActive()` for attachment timeline propagation across linked meshes.
  - Added `SliderTimeline` and `SliderMixTimeline` for animating sliders
  - Added new pose system with `BoneLocal`, `BonePose`, and related classes for improved transform handling
  - Added `Pose`, `Posed`, and `PosedActive` base classes for unified pose management
  - Added `ConstraintTimeline` interface for unified constraint timeline indexing
  - Added `Animation::getBones()` to get bone indices used by an animation
  - Added template method `SkeletonData::findConstraint<T>()` for type-safe constraint queries
  - Added `SkeletonRenderer` class with `RenderCommand` for batched rendering
  - Added `HasRendererObject` interface for attachments with renderer-specific data
  - Ported the latest parser fixes from spine-libgdx, including the 4.3 path constraint flag fix and the weighted mesh binary vertex allocation/count fix.
  - Ported the latest additive timeline updates and alpha/RGB timeline flicker fixes from spine-libgdx.
  - Ported the AnimationState additive/hold rework from spine-libgdx. `MixBlend` and `MixDirection` are no longer used by timelines. The new system uses `bool fromSetup, bool add, bool out` parameters and a bitmask-based hold system that replaces `holdPrevious` and `interruptAlpha`.
  - Added `Timeline::getAdditive()` and `Timeline::getInstant()` to query timeline blending capabilities.
  - Added `TrackEntry::getAdditive()` / `TrackEntry::setAdditive()` to control additive blending per track entry.
  - Ported the Skin placeholder name rename from spine-libgdx. `Skin::AttachmentMap::Entry::_name` renamed to `_placeholderName`.
  - Fixed `SkeletonBinary::readLong()` sign extension bug that truncated 64-bit hash values to 32 bits.
  - Ported the sequence attachment refactor from spine-libgdx. `Sequence` now precomputes per-frame regions, UVs, and region offsets, and `RegionAttachment` / `MeshAttachment` now mirror the libgdx implementation.
  - Ported the latest clipping runtime changes from spine-libgdx, including convex and inverse clipping support and the inverse clipping crash fix.
  - Added `ClippingAttachment::getConvex()` / `setConvex()` and `getInverse()` / `setInverse()`.
  - Added `Animation::getColor()` and `BoneData` icon size/rotation accessors for nonessential editor data.

- **Bug fixes**
  - Fixed draw order timelines not mixing out to the setup pose.
  - Fixed slider sorting crashes when slider animations key slot or constraint timelines.
  - Fixed bones that don't inherit rotation when parent scale is near zero.
  - Fixed `BonePose::updateLocalTransform()` for `noScale` and `noScaleOrReflection` inheritance, plus related IK epsilon handling.
  - Fixed `ScaleYMode_Volume` to avoid extreme scaleY values for very small scaleX factors.
  - Fixed `InheritTimeline` so inherit keys are applied to the keyed bone instead of an uninitialized bone index.
  - Fixed `AnimationState` attachment timeline handling so deforms are applied correctly when an attachment is hidden in the setup pose.
  - Fixed `Skeleton::updateWorldTransform()` to avoid copying draw order unless it is constrained.

- **Breaking changes**
  - `MathUtil::Epsilon2` renamed to `MathUtil::EpsilonSq`.
  - `BonePose::resetWorld()` is now private.
  - `AttachmentLoader` methods now receive both the skin `placeholder` and resolved attachment `name`. `Skin::AttachmentMap::Entry::_placeholderName` renamed to `_placeholder`.
  - `AnimationState::getCurrent()` renamed to `AnimationState::getTrack()`.
  - `MeshAttachment::getParentMesh()` / `setParentMesh()` renamed to `getSourceMesh()` / `setSourceMesh()`.
  - Headers reorganized from `spine-cpp/spine-cpp/include/spine/` to `spine-cpp/include/spine/`
  - Timeline `apply()` signature changed: `MixBlend blend, MixDirection direction` replaced with `bool fromSetup, bool add, bool out`. All timeline subclasses updated.
  - `Animation::apply()` signature changed to match the new timeline parameters.
  - `CurveTimeline1::getRelativeValue()`, `getAbsoluteValue()`, and `getScaleValue()` signatures changed from `MixBlend`/`MixDirection` to `bool fromSetup, bool add, bool out`.
  - `TrackEntry::getHoldPrevious()` / `setHoldPrevious()` removed. Use `TrackEntry::getAdditive()` / `setAdditive()` instead for additive blending.
  - `TrackEntry::getMixBlend()` / `setMixBlend()` removed.
  - `TrackEntry::_interruptAlpha` removed.
  - `Skin::AttachmentMap::Entry::_name` renamed to `_placeholderName`. All `Skin` methods use `placeholderName` parameter names instead of `name`/`attachmentName`.
  - `AnimationState` hold constants changed: `HoldSubsequent` and `HoldMix` removed, replaced with bitmask system (`Subsequent=0, First=1, Hold=2, HoldFirst=3`).
  - `Bone` now extends `PosedActive` with separate pose, constrained, and applied states
  - `IkConstraintData::getUniform()` / `setUniform()` replaced by `getScaleY()` / `setScaleY()` and `ScaleY` (`none`, `uniform`, `volume`).
  - `IkConstraintData::getScaleY()` / `setScaleY()` and `ScaleY` renamed to `getScaleYMode()` / `setScaleYMode()` and `ScaleYMode`.
  - `BoneData::getSetupPose()` and `Bone::getPose()` now use `BonePose` instead of `BoneLocal`. Bone timelines and parser setup pose data were updated to match the spine-libgdx `BoneLocal` removal.
  - Renamed timeline constraint index methods to use unified `getConstraintIndex()`
  - Changed timeline class hierarchy with new base classes `BoneTimeline`, `SlotCurveTimeline`, and `ConstraintTimeline`
  - Sequence attachments now use the new non-null `Sequence` model. `RegionAttachment` and `MeshAttachment` were refactored to match spine-libgdx and no longer use the old lazy mutable region update path.
  - Renamed setup pose methods:
    ||||
    |-----|-|-----|
    | `Skeleton::setToSetupPose()`          |→| `Skeleton::setupPose()` |
    | `Skeleton::setBonesToSetupPose()`     |→| `Skeleton::setupPoseBones()` |
    | `Skeleton::setSlotsToSetupPose()`     |→| `Skeleton::setupPoseSlots()` |
    | Bone::setToSetupPose()                |→| Bone::setupPose() |
    | Slot::setToSetupPose()                |→| Slot::setupPose() |
    | IkConstraint::setToSetupPose()        |→| IkConstraint::setupPose() |
  - `EventData` now stores shared payload defaults in `EventData::getSetupPose()` instead of directly on `EventData`. Use the returned `Event` for setup int, float, string, volume, and balance values.
  - `Animation` now constructs with only a name. Call `setTimelines(timelines, bones)` and `setDuration()` after loading timelines.
    | TransformConstraint::setToSetupPose() |→| TransformConstraint::setupPose() |
    | PathConstraint::setToSetupPose()      |→| PathConstraint::setupPose() |
    | PhysicsConstraint::setToSetupPose()   |→| PhysicsConstraint::setupPose() |
  - `Bone` local transform properties moved to `bone.getPose()`:
    ||||
    |-----|-|-----|
    | bone.getX()        |→| bone.getPose().getX()        |
    | bone.getY()        |→| bone.getPose().getY()        |
    | bone.getRotation() |→| bone.getPose().getRotation() |
    | bone.getScaleX()   |→| bone.getPose().getScaleX()   |
    | bone.getScaleY()   |→| bone.getPose().getScaleY()   |
    | bone.getShearX()   |→| bone.getPose().getShearX()   |
    | bone.getShearY()   |→| bone.getPose().getShearY()   |
  - `Bone` world and applied transform properties moved to `bone.getAppliedPose()`:
    ||||
    |-----|-|-----|
    | bone.getWorldX()        |→| bone.getAppliedPose().getWorldX()        |
    | bone.getWorldY()        |→| bone.getAppliedPose().getWorldY()        |
    | bone.getWorldRotationX()|→| bone.getAppliedPose().getWorldRotationX()|
    | bone.getWorldRotationY()|→| bone.getAppliedPose().getWorldRotationY()|
    | bone.getWorldScaleX()   |→| bone.getAppliedPose().getWorldScaleX()   |
    | bone.getWorldScaleY()   |→| bone.getAppliedPose().getWorldScaleY()   |
    | bone.getA()             |→| bone.getAppliedPose().getA()             |
    | bone.getB()             |→| bone.getAppliedPose().getB()             |
    | bone.getC()             |→| bone.getAppliedPose().getC()             |
    | bone.getD()             |→| bone.getAppliedPose().getD()             |
  - `Slot` properties moved to `slot.getPose()`:
    ||||
    |-----|-|-----|
    | slot.getColor()             |→| slot.getPose().getColor()             |
    | slot.getDarkColor()         |→| slot.getPose().getDarkColor()         |
    | slot.getAttachment()        |→| slot.getPose().getAttachment()        |
    | slot.getHasSecondColor()    |→| slot.getPose().getHasSecondColor()    |
    | slot.getDeform()            |→| slot.getPose().getDeform()            |
  - `IkConstraint` properties moved to `ikConstraint.getPose()`:
    ||||
    |-----|-|-----|
    | ikConstraint.getMix()           |→| ikConstraint.getPose().getMix()           |
    | ikConstraint.getSoftness()      |→| ikConstraint.getPose().getSoftness()      |
    | ikConstraint.getBendDirection() |→| ikConstraint.getPose().getBendDirection() |
    | ikConstraint.getCompress()      |→| ikConstraint.getPose().getCompress()      |
    | ikConstraint.getStretch()       |→| ikConstraint.getPose().getStretch()       |
  - `TransformConstraint` properties moved to `transformConstraint.getPose()`:
    ||||
    |-----|-|-----|
    | transformConstraint.getMixRotate() |→| transformConstraint.getPose().getMixRotate() |
    | transformConstraint.getMixX()      |→| transformConstraint.getPose().getMixX()      |
    | transformConstraint.getMixY()      |→| transformConstraint.getPose().getMixY()      |
    | transformConstraint.getMixScaleX() |→| transformConstraint.getPose().getMixScaleX() |
    | transformConstraint.getMixScaleY() |→| transformConstraint.getPose().getMixScaleY() |
    | transformConstraint.getMixShearY() |→| transformConstraint.getPose().getMixShearY() |
  - `PathConstraint` properties moved to `pathConstraint.getPose()`:
    ||||
    |-----|-|-----|
    | pathConstraint.getPosition()   |→| pathConstraint.getPose().getPosition()   |
    | pathConstraint.getSpacing()    |→| pathConstraint.getPose().getSpacing()    |
    | pathConstraint.getMixRotate()  |→| pathConstraint.getPose().getMixRotate()  |
    | pathConstraint.getMixX()       |→| pathConstraint.getPose().getMixX()       |
    | pathConstraint.getMixY()       |→| pathConstraint.getPose().getMixY()       |
  - `PhysicsConstraint` properties moved to `physicsConstraint.getPose()`:
    ||||
    |-----|-|-----|
    | physicsConstraint.getMix()         |→| physicsConstraint.getPose().getMix()         |
    | physicsConstraint.getGravity()     |→| physicsConstraint.getPose().getGravity()     |
    | physicsConstraint.getStrength()    |→| physicsConstraint.getPose().getStrength()    |
    | physicsConstraint.getDamping()     |→| physicsConstraint.getPose().getDamping()     |
    | physicsConstraint.getMassInverse() |→| physicsConstraint.getPose().getMassInverse() |
    | physicsConstraint.getWind()        |→| physicsConstraint.getPose().getWind()        |
  - `ConstraintData` properties moved to `constraintData.getSetupPose()`:
    ||||
    |-----|-|-----|
    | ikConstraintData.getMix() |→| ikConstraintData.getSetupPose().getMix() |
    | ...| |...|
  - `SkeletonData` now provides a single `ConstraintData` list `getConstraints()` instead of separate lists per constraint type:
    ||||
    |-----|-|-----|
    | skeletonData.getIkConstraints()        |→| Filter skeletonData.getConstraints() for IkConstraintData instances |
    | skeletonData.getTransformConstraints() |→| Filter skeletonData.getConstraints() for TransformConstraintData instances |
    | skeletonData.getPathConstraints()      |→| Filter skeletonData.getConstraints() for PathConstraintData instances |
    | skeletonData.getPhysicsConstraints()   |→| Filter skeletonData.getConstraints() for PhysicsConstraintData instances |
  - `SkeletonData` now provides unified `findConstraint<T>()` template method:
    ||||
    |-----|-|-----|
    | skeletonData.findIkConstraint(name)        |→| skeletonData.findConstraint<IkConstraintData>(name) |
    | skeletonData.findTransformConstraint(name) |→| skeletonData.findConstraint<TransformConstraintData>(name) |
    | skeletonData.findPathConstraint(name)      |→| skeletonData.findConstraint<PathConstraintData>(name) |
    | skeletonData.findPhysicsConstraint(name)   |→| skeletonData.findConstraint<PhysicsConstraintData>(name) |
  - `Physics` enum moved from nested `Skeleton::Physics` to standalone `spine::Physics`
    - `updateWorldTransform(Skeleton::Physics::update)` → `updateWorldTransform(spine::Physics::update)`
  - Timeline `apply()` methods now take an additional `appliedPose` parameter
  - Attachment `computeWorldVertices()` methods now take an additional `skeleton` parameter
  - Renamed timeline constraint index methods to use unified `getConstraintIndex()`
  - API changes to match reference runtime naming conventions:
    - `addAnimationWith()` → `addAnimation()`
    - `setAnimationWith()` → `setAnimation()`
    - `setMixWith()` → `setMix()`
    - `setSkinByName()` → `setSkin()`
    - `getAttachmentByName()` → `getAttachment()`

### Cocos2d-x
- The runtime has been removed, as Cocos2d-x has not been maintained in years, and the latest version no longer compiles out of the box on macOS, iOS, and other platforms.

### SFML

- **Restructuring**
  - Reorganized directory structure - merged C and C++ examples into a single structure
  - Moved from `spine-sfml/c/` and `spine-sfml/cpp/` to unified `spine-sfml/` structure
  - Added CMakePresets.json for modern CMake configuration
  - Simplified example structure with single main.cpp

- **Breaking changes**
  - Updated to use new C++ runtime with all breaking changes above

### UE

- **Additions**
  - Added Blueprint APIs for `TrackEntry` mix interpolation.
  - Added convex and inverse clipping support through the updated spine-cpp clipping runtime.

- **Breaking changes**
  - Custom C++ `AttachmentLoader` implementations now receive both the skin `placeholder` and resolved attachment `name`.
  - `USpineSkeletonAnimationComponent::GetCurrent()` renamed to `GetTrack()`.
  - `USpineWidget::GetCurrent()` renamed to `GetTrack()`.
  - Updated to use new C++ runtime with all breaking changes above

### Godot

- **Additions**
  - Added `SpineSliderData.get_max()` / `set_max()` for nonessential bone-driven slider metadata.
  - Added `SpinePhysicsConstraintData.get_scale_y_mode()` / `set_scale_y_mode()`.
  - Added `SpineTrackEntry` mix interpolation APIs and `SpineConstant.MixInterpolation`.
  - Added convex and inverse clipping support through the updated spine-cpp clipping runtime.
  - Added `SpineSlider` and `SpineSliderData` classes for slider constraints
  - Added `SpineTrackEntry.get_additive()` / `set_additive()` for additive blending per track entry.

- **Bug fixes**
  - Fixed draw order timelines not mixing out to the setup pose.
  - Fixed editor crashes when assigning skeleton data with slider animations that key slots or constraints.
  - Fixed attachment timelines so hidden setup-pose attachments remain hidden while mixing out, preserving deform behavior.
  - Fixed `SpineAnimationTrack` editor preview paths for nested `AnimationPlayer` roots, and prevented inactive tracks from clearing `SpineSprite` preview animations.
  - Fixed GDExtension animation mix editing in the Godot inspector.
  - Fixed `SpineBoneNode` and `SpineSlotNode` transforms when bones use negative scale or shear, and applied `SpineBoneNode` Drive mode before world transforms are computed.
  - Updated Godot 4.x CI builds to Godot 4.6.2.
  - Fixed Godot 4.6 Windows editor CI builds by installing Direct3D 12 SDK dependencies before building Godot.
  - Fixed Godot 4.6 GDExtension builds with the latest `godot-cpp` by including the required `Ref` support header in `SpineCommon.h`, updated `SpineEventData` for the `EventData.setupPose` API change, and refreshed vendored `spine-cpp` sources during clean setup.
  - Fixed Godot 3.x builds by avoiding the Godot 4-only `Transform2D(Vector2, Vector2, Vector2)` constructor.

- **Breaking changes (since previous 4.3 beta)**
  - `SpineSkin` attachment method argument names now use `placeholder` instead of `name`.
  - `SpineTrackEntry.get_hold_previous()` / `set_hold_previous()` removed.
  - `SpineTrackEntry.get_mix_blend()` / `set_mix_blend()` removed. Use `get_additive()` / `set_additive()` for additive blending.
  - `SpineConstant.MixBlend` and `SpineConstant.MixDirection` enums removed.
  - `SpineTimeline.apply()` signature changed: `blend` and `direction` parameters replaced with `from_setup`, `add`, `out`.
  - `SpineAnimation.apply()` signature changed to match.
  - `SpineAnimationTrack` property `hold_previous` replaced with `additive`, property `mix_blend` removed.
  - Added `SpineBoneLocal` and `SpineBonePose` classes for new pose system
  - Added pose classes for constraints: `SpineIkConstraintPose`, `SpinePathConstraintPose`, `SpinePhysicsConstraintPose`, `SpineSliderPose`, `SpineTransformConstraintPose`
  - `SpineIkConstraintData.get_scale_y()` / `set_scale_y()` and `SpineConstant.ScaleY` renamed to `get_scale_y_mode()` / `set_scale_y_mode()` and `SpineConstant.ScaleYMode`.

- **Breaking changes**
  - `SpineAnimationState.get_current()` renamed to `SpineAnimationState.get_track()` in the GDScript API.
  - Updated to use new C++ pose system internally
  - `SpineBone.get_pose()` and `SpineBoneData.get_setup_pose()` now return `SpineBonePose` to match the updated spine-cpp bone pose API.
  - Removed from `SpineBone`: `update_world_transform()`, `set_to_setup_pose()`, `get_world_to_local_rotation_x()`, `get_world_to_local_rotation_y()`
  - Removed direct property access from `SpineBone`: `get_x()`, `set_x()`, `get_y()`, `set_y()`, `get_rotation()`, `set_rotation()`, etc. - use pose objects instead
  - `SpineAnimation.apply()` now takes an additional `appliedPose` parameter
  - Note: `SpineSkeleton` still maintains `set_to_setup_pose()`, `set_bones_to_setup_pose()`, `set_slots_to_setup_pose()` for compatibility

## C#

- **Additions**
  - Added `Slider` and `SliderData` classes for slider constraints
  - Added `SliderTimeline` and `SliderMixTimeline` for animating sliders
  - Added new pose system with `BonePose` and related classes
  - Added `IPose`, `Posed`, and `PosedActive` base classes for unified pose management
  - Added `IConstraintTimeline` interface for unified constraint timeline indexing
  - Added `Animation.Bones` property to get bone indices used by an animation
  - Added `Skeleton` properties `GravityX`, `GravityY`, `WindX`, `WindY` to allow rotating physics force directions
  - Added `Color32F` class used in new `.GetColor()` and `.SetColor()` methods replacing `.R` `.G` `.B` `.A` properties
  - Linked meshes can now inherit deform and sequence timelines from source meshes in different slots
  - Added `Attachment.TimelineSlots` and `Attachment.IsTimelineActive()` for attachment timeline propagation across linked meshes
  - Added `DrawOrderFolderTimeline` for animating draw order folders
  - Added `ClippingAttachment.Convex` and `ClippingAttachment.Inverse`
  - Added `IkConstraintData.ScaleYMode` enum and `IkConstraintData.ScaleY` to control how IK compress/stretch changes `BonePose.ScaleY`, including volume preservation
  - Added `allowMissingRegions` parameter to `AtlasAttachmentLoader` constructor to support skeletons exported with per-skin atlases
  - `TrackEntry.Reverse` animations now fire events. Previously events were not fired when an animation was played in reverse.
  - Added `TrackEntry.MixInterpolation` for customizable non-linear mixing. Defaults to `Interpolation.Linear` to maintain existing behaviour.

- **Breaking changes**
  - Color properties `.R` `.G` `.B` `.A` are replaced by `.GetColor()` and `.SetColor()`
  - Dark color properties `.R2` `.G2` `.B2` are replaced by `.GetDarkColor()` and `.SetDarkColor()`
  - `Bone` now extends `PosedActive` with separate pose, constrained, and applied states
  - `Bone` local transform properties moved to `Bone.Pose`:
    ||||
    |---------------|-|-------------|
    | Bone.X        |→| Bone.Pose.X |
    | Bone.Y        |→| Bone.Pose.Y |
    | Bone.Rotation |→| Bone.Pose.Rotation |
    | Bone.ScaleX   |→| Bone.Pose.ScaleX |
    | Bone.ScaleY   |→| Bone.Pose.ScaleY |
    | Bone.ShearX   |→| Bone.Pose.ShearX |
    | Bone.ShearY   |→| Bone.Pose.ShearY |
  - `Bone` world and applied transform properties moved to `Bone.AppliedPose`:
    ||||
    |---------------------|-|--------------------|
    | Bone.AX             |→| Bone.AppliedPose.X |
    | Bone.AY             |→| Bone.AppliedPose.Y |
    | Bone.ARotation      |→| Bone.AppliedPose.Rotation |
    | Bone.AScaleX        |→| Bone.AppliedPose.ScaleX |
    | Bone.AScaleY        |→| Bone.AppliedPose.ScaleY |
    | Bone.AShearX        |→| Bone.AppliedPose.ShearX |
    | Bone.AShearY        |→| Bone.AppliedPose.ShearY |
    | Bone.WorldX         |→| Bone.AppliedPose.WorldX |
    | Bone.WorldY         |→| Bone.AppliedPose.WorldY |
    | Bone.WorldRotationX |→| Bone.AppliedPose.WorldRotationX |
    | Bone.WorldRotationY |→| Bone.AppliedPose.WorldRotationY |
  - `Bone` no longer provides a `Bone.Skeleton` property, constructor no longer takes a `skeleton` parameter
  - `Slot` properties moved to `SlotPose`, i.e. `Slot.AppliedPose`:
    ||||
    |-----------------------|-|-----------------------------|
    | Slot.Attachment       |→| Slot.AppliedPose.Attachment |
    | Slot.R .G .B .A       |→| Slot.AppliedPose.GetColor() and Slot.AppliedPose.SetColor() |
    | Slot.R2 .G2 .B2       |→| Slot.AppliedPose.GetDarkColor() and Slot.AppliedPose.SetDarkColor() |
    | Slot.HasSecondColor   |→| Slot.AppliedPose.HasDarkColor |
    | Slot.Deform           |→| Slot.AppliedPose.Deform |
    | Slot.SequenceIndex    |→| Slot.AppliedPose.SequenceIndex |
  - `Constraint` properties moved to `Constraint.Pose`:
    ||||
    |-----------------------------|-|-----------------------|
    | IkConstraint.Mix            |→| IkConstraint.Pose.Mix |
    | IkConstraint.Softness       |→| IkConstraint.Pose.Softness |
    | IkConstraint.BendDirection  |→| IkConstraint.Pose.BendDirection |
    | IkConstraint.Compress       |→| IkConstraint.Pose.Compress |
    | IkConstraint.Stretch        |→| IkConstraint.Pose.Stretch |

    ||||
    |-------------------------------|-|------------------------------------|
    | TransformConstraint.MixRotate |→| TransformConstraint.Pose.MixRotate |
    | TransformConstraint.MixX      |→| TransformConstraint.Pose.MixX |
    | TransformConstraint.MixY      |→| TransformConstraint.Pose.MixY |
    | TransformConstraint.MixScaleX |→| TransformConstraint.Pose.MixScaleX |
    | TransformConstraint.MixScaleY |→| TransformConstraint.Pose.MixScaleY |
    | TransformConstraint.MixShearY |→| TransformConstraint.Pose.MixShearY |

    ||||
    |---------------------------|-|------------------------------|
    | PathConstraint.Position   |→| PathConstraint.Pose.Position |
    | PathConstraint.Spacing    |→| PathConstraint.Pose.Spacing |
    | PathConstraint.MixRotate  |→| PathConstraint.Pose.MixRotate |
    | PathConstraint.MixX       |→| PathConstraint.Pose.MixX |
    | PathConstraint.MixY       |→| PathConstraint.Pose.MixY |

    ||||
    |-------------------------------|-|----------------------------|
    | PhysicsConstraint.Mix         |→| PhysicsConstraint.Pose.Mix |
    | PhysicsConstraint.Gravity     |→| PhysicsConstraint.Pose.Gravity |
    | PhysicsConstraint.Strength    |→| PhysicsConstraint.Pose.Strength |
    | PhysicsConstraint.Damping     |→| PhysicsConstraint.Pose.Damping |
    | PhysicsConstraint.MassInverse |→| PhysicsConstraint.Pose.MassInverse |
    | PhysicsConstraint.Wind        |→| PhysicsConstraint.Pose.Wind |
  - `ConstraintData` properties moved to `ConstraintData.GetSetupPose()`
    ||||
    |-----|-|-----|
    | IkConstraintData.Mix |→| IkConstraintData.GetSetupPose().Mix |
    | ...| |...|

  - `SkeletonData` now provides a single `IConstraintData` list `SkeletonData.Constraints` instead of separate lists per constraint type
    ||||
    |-----|-|-----|
    | SkeletonData.IkConstraints        |→| SkeletonData.Constraints.OfType\<IkConstraintData\>() |
    | SkeletonData.TransformConstraints |→| SkeletonData.Constraints.OfType\<TransformConstraintData\>() |
    | SkeletonData.PathConstraints      |→| SkeletonData.Constraints.OfType\<PathConstraintData\>() |
    | SkeletonData.PhysicsConstraints   |→| SkeletonData.Constraints.OfType\<PhysicsConstraintData\>() |
  - `SkeletonData` now provides `SkeletonData.FindConstraint<ConstraintData>()` instead of single find methods per constraint type
    ||||
    |-----|-|-----|
    | SkeletonData.FindIkConstraint        |→| SkeletonData.FindConstraint\<IkConstraintData\>() |
    | SkeletonData.FindTransformConstraint |→| SkeletonData.FindConstraint\<TransformConstraintData\>() |
    | SkeletonData.FindPathConstraint      |→| SkeletonData.FindConstraint\<PathConstraintData\>() |
    | SkeletonData.FindPhysicsConstraint   |→| SkeletonData.FindConstraint\<PhysicsConstraintData\>() |
  - Renamed setup pose methods:
    ||||
    |-----|-|-----|
    | `Skeleton.SetToSetupPose()`       |→| `Skeleton.SetupPose()` |
    | `Skeleton.SetBonesToSetupPose()`  |→| `Skeleton.SetupPoseBones()` |
    | `Skeleton.SetSlotsToSetupPose()`  |→| `Skeleton.SetupPoseSlots()` |
    | Bone.SetToSetupPose()           |→| Bone.SetupPose() |
    | Slot.SetToSetupPose()           |→| Slot.SetupPose() |
    | IkConstraint.SetToSetupPose()   |→| IkConstraint.SetupPose() |
  - `Skeleton.Physics` was moved to `Physics` directly in `Spine` namespace
    - `UpdateWorldTransform(Skeleton.Physics.Update)` → `UpdateWorldTransform(Spine.Physics.Update)`
  - Timeline `Apply()` methods now take an additional `appliedPose` parameter
  - Attachment `ComputeWorldVertices()` methods now take an additional `skeleton` parameter
  - Renamed timeline constraint index methods to use unified `ConstraintIndex` property
  - Reorganized timeline class hierarchy with new base classes
  - Removed `AtlasAttachmentLoader` method `AtlasRegion FindRegion(string name)` from public interface. Added `protected AtlasRegion FindRegion(string name, string path)` instead which may be overridden instead when deriving your own subclass.
  - Removed `TrackEntry.HoldPrevious` and `TrackEntry.InterruptAlpha`. New `AnimationState` hold system automatically calculates the required state values.
  - Removed `BoneLocal` class. `BonePose` now directly implements `IPose<BonePose>` and contains all local pose fields. Replace any use of `BoneLocal` → `BonePose`.
  - `EventData` no longer stores `Int`, `Float`, `String`, `Volume`, and `Balance` properties directly. Use `EventData.SetupPose` to access the setup pose `Event` which provides these properties instead.
    ||||
    |-----|-|-----|
    | `EventData.Int`     |→| `EventData.SetupPose.Int` |
    | `EventData.Float`   |→| `EventData.SetupPose.Float` |
    | `EventData.String`  |→| `EventData.SetupPose.String` |
    | `EventData.Volume`  |→| `EventData.SetupPose.Volume` |
    | `EventData.Balance` |→| `EventData.SetupPose.Balance` |
  - `Timeline.PropertyIds` type changed from `string[]` to `ulong[]`. `Animation.HasTimeline()` parameter and Timeline constructors changed accordingly.
  - `Skeleton.DrawOrder` type changed from `ExposedList<Slot>` to `DrawOrder` class. Use `Skeleton.DrawOrder.AppliedPose` for rendering and `Skeleton.DrawOrder.Pose` for changing the draw order.
  - `IkConstraintData.Uniform` replaced by `IkConstraintData.ScaleY`. `IkConstraint.Apply()` methods now take `ScaleY` instead of a `bool uniform` parameter.
  - `MeshAttachment.ParentMesh` renamed to `MeshAttachment.SourceMesh`
  - `AttachmentLoader` methods `NewRegionAttachment`, `NewMeshAttachment`, `NewBoundingBoxAttachment`, `NewClippingAttachment`, `NewPathAttachment`, and `NewPointAttachment` now take an additional `string placeholder` parameter. Update any custom `AttachmentLoader` implementations accordingly.
  - Renamed `Skin.SkinEntry.Name` to `Skin.SkinEntry.Placeholder` to better match Spine editor terminology. Was intermediately renamed to `PlaceholderName` which was then changed to `Placeholder`.
  - `MathUtils.IInterpolation` class is replaced by new `Interpolation` class, see *Additions* above.
  - `AnimationState.SetCurrent()` renamed to `AnimationState.SetTrack()`; `AnimationState.GetCurrent()` renamed to `AnimationState.GetTrack()`.
    ||||
    |-----|-|-----|
    | `AnimationState.SetCurrent()`     |→| `AnimationState.SetTrack()` |
    | `AnimationState.GetCurrent()`     |→| `AnimationState.GetTrack()` |

### Unity

- **Officially supported Unity versions are 2017.1-6000.4**.

- **Breaking changes**
  - Updated to use new C# runtime with all breaking changes above
  - **MAJOR ARCHITECTURE CHANGE: Main skeleton components have been split into separate rendering and animation components.** Components will be automatically upgraded when scenes/prefabs are opened in the Unity Editor. See the `Documentation/4.3-split-component-upgrade-guide.md` document for detailed migration instructions. The major changes are:
    - `SkeletonAnimation` is now split into `SkeletonAnimation` + `SkeletonRenderer` components
    - `SkeletonMecanim` is now split into `SkeletonMecanim` + `SkeletonRenderer` components
    - `SkeletonGraphic` is now split into `SkeletonAnimation` + `SkeletonGraphic` components
  - Example skeletons in Spine Examples are now using straight alpha textures and materials for better compatibility with Linear colorspace.
  - `Skeleton.Physics` was moved to `Physics` directly in `Spine` namespace, thus might clash with `UnityEngine.Physics`.
    - Spine Physics: `UpdateWorldTransform(Skeleton.Physics.Update)` → `UpdateWorldTransform(Spine.Physics.Update)`
    - UnityEngine Physics: `Physics.gravity` → `UnityEngine.Physics.gravity`.
  - `SkeletonRenderer`: `maskInteraction` → `MaskInteraction`.
  - Removed rather useless old menu entries `GameObject - Spine - SkeletonRenderer` and the like which are spawning e.g. a GameObject with an empty `SkeletonRenderer` component without `SkeletonDataAsset` assigned and thus also not initialized properly.
  - Removed `attachment.GetRemappedClone()` extension methods. Replace `attachment.GetRemappedClone(parameters)` with `attachment.Copy(); attachment.SetRegion(parameters)`. Removed `AttachmentCloneExtensions` class, `SetRegion` methods are now in `AttachmentRegionExtensions`.
  - Renamed `ToAtlasRegionPMAClone` to `ToAtlasRegionWithNewPMATexture`.
  - Renamed `ToRegionAttachmentPMAClone` to `ToRegionAttachmentWithNewPMATexture`.
  - Removed support for long abandoned thirdparty asset "2D Toolkit" (TK2D) by Unikron Software.
  - Removed Spine Timeline `Spine Animation State Clip` property `Hold Previous`. New `AnimationState` hold system automatically calculates the required state values.
  - Removed intermediately added (4.3-beta branch only) `SkeletonAnimation` callbacks `MainThreadStart`, `MainThreadInterrupt`, `MainThreadEnd`, `MainThreadDispose`, `MainThreadComplete` and `MainThreadEvent`. Instead `SkeletonAnimation.AnimationState` and `TrackEntry` events are now automatically  processed on the main thread. There is no longer a change of user code required for these events, and `TrackEntry` events can be utilized directly even with threaded animation enabled.
  - `SkeletonGraphic` property `CustomSlotMaterials` now properly assigns the override material directly instead of assigning the texture of the override material, which was of little use.

- **Changes of default values**
  - Changed default atlas texture workflow from PMA to straight alpha textures. This move was done because straight alpha textures are compatible with both Gamma and Linear color space, with the latter being the default for quite some time now in Unity. Note that `PMA Vertex Color` is unaffected and shall be enabled as usual to allow for single-pass additive rendering.

- **Additions**
  - Added Spine Preferences `Switch Texture Workflow` functionality to quickly switch to the respective PMA or straight-alpha texture and material presets.
  - Added a workflow mismatch dialog showing whenever problematic PMA vs. straight alpha settings are detected at a newly imported `.atlas.txt` file. Invalid settings include the atlas being PMA and project using Linear color space, and a mismatch of Auto-Import presets set to straight alpha compared to the atlas being PMA and vice versa. The dialog offers an option to automatically fix the problematic setting on the import side and links website documentation for export settings. This dialog can be disabled and re-enabled via Spine preferences.
  - Added threading support for all skeleton rendering and animation components, disabled by default. Threading can be activated per component or globally via Edit → Preferences → Spine → Threading Defaults. Two threading options are available:
    - `Threaded MeshGeneration`: Default value for SkeletonRenderer and SkeletonGraphic threaded mesh generation
    - `Threaded Animation`: Default value for SkeletonAnimation and SkeletonMecanim threaded animation updates
  - Even when threading is enabled, the threading system defaults to  `SkeletonRenderer` and `SkeletonAnimation` user callbacks like `UpdateWorld` (not including `AnimationState` callbacks) being issued on the main thread to support existing user code. Can be configured via `SkeletonUpdateSystem.Instance.MainThreadUpdateCallbacks = false` to perform callbacks on worker threads if parallel execution is supported and desired by the user code. `OnPostProcessVertices` is an exception, as it it's deliberately left on worker threads so that parallellization can be utilized. Note that most Unity API calls are restricted to the main thread.
  - Added `SkeletonUpdateSystem.Instance.GroupRenderersBySkeletonType` and `GroupAnimationBySkeletonType` properties. Defaults to disabled. Later when smart partitioning is implemented, enabling this parameter might slightly improve cache locality. Until then having it enabled combined with different skeleton complexity would lead to worse load balancing.
  - Added previously missing editor drag & drop skeleton instantiation option *SkeletonGraphic (UI) Mecanim* combining components `SkeletonGraphic` and `SkeletonMecanim`.
  - Added define `SPINE_DISABLE_THREADING` to disable threaded animation and mesh generation entirely, removing the respective code. This define can be set as `Scripting Define Symbols` globally or for selective build profiles where desired.
  - Added automatic load balancing (work stealing) for improved performance when using threaded animation and mesh generation, enabled by default. Load balancing can be disabled via a new Spine preferences parameter `Threading Defaults - Load Balancing` setting a build define accordingly.
    Additional configuration parameters `SkeletonUpdateSystem.UpdateChunksPerThread` and `LateUpdateChunksPerThread` are available to fine-tune the chunk count for load balancing. A minimum of 8 chunks is recommended with load balancing enabled. Higher values add higher overhead with potentially detrimental effect on performance.
  - Spine UI Toolkit UPM package now supports rendering back-face triangles. Enable `Flip Back Faces` to automatically fix back-face geometry in an additional pass (defaults to enabled). Disable the setting to save additional processing overhead.
  - Spine UI Toolkit UPM package now supports PMA atlas textures. At the `SpineVisualElement` expand `Blend Mode Materials` and hit `Detect Materials` to automatically assign the proper PMA or straight alpha material at `Normal Material`. Unity minimum version increased to 6000.3 which added  support for UI Toolkit materials.
  - Spine UI Toolkit UPM package now supports all Spine blend modes via blend mode materials and multiple materials per skeleton. Enable `Multiple Materials` (enabled by default), expand `Blend Mode Materials` and hit `Detect Materials` to automatically assign the correct PMA or straight alpha blend mode materials.
  - Every Spine URP shader now has an `Outline` option to switch to the respective Outline shader variant. Uses multi-pass support of newer URP versions. Requires spine-unity core package version 4.3.44 or newer due to required modifications in custom Sprite Shader GUI.
  - Added new variants of `GetRepackedSkin` and `GetRepackedAttachments` supporting blend modes. These new variants take a packing configuration input struct `RepackAttachmentsSettings` which provides optional `additiveMaterialSource`, `multiplyMaterialSource` and `screenMaterialSource` properties, enabling blend mode repacking when any is non-null. Create your `RepackAttachmentsSettings` from default settings via `RepackAttachmentsSettings.Default` and then customize settings as needed. Blend mode materials can be set at once using `UseSourceMaterialsFrom(SkeletonDataAsset)` or `UseBlendModeMaterialsFrom(SkeletonDataAsset)`. Uses new `RepackAttachmentsOutput` struct providing `DestroyGeneratedAssets` to easily destroy any previously generated assets.
  - Updated example scenes to demonstrate new `GetRepackedSkin` variant usage.
  - AnimationReferenceAsset: Added animation selector drop-down popup next to object assignment field for easy initial assignment and animation switching. Shows red warning color if the assigned AnimationReferenceAsset's SkeletonDataAsset does not match the one at the GameObjects `SkeletonAnimation` component. A mismatch may be intentional for a special split SkeletonDataAsset setup. Warning color can be disabled in `Edit - Preferences - Spine`, `Warnings - SkeletonDataAsset Mismatch Warning`.
  - AnimationReferenceAssets: The `SkeletonDataAsset` Inspector now generates the set of AnimationReferenceAssets as nested assets below a single asset `<skeletonname>_AnimationReferences.asset` to avoid cluttering the project with hundreds of asset files. This also makes searching the project for a suitable `AnimationReferenceAsset` of a given `SkeletonDataAsset` much faster. Use of existing old individual assets is still supported alongside nested new ones. If you require the old way of creating assets in your project, add `SPINE_INDIVIDUAL_ANIMATION_REFERENCE_ASSETS` to your project's Scripting Define Symbols.
  - AnimationReferenceAssets: Added Spine Preferences setting `Editor Instantiation` - `Warnings - SkeletonDataAsset Mismatch Warning` to disable the warning color when a different SkeletonDataAsset is detected at the `AnimationReferenceAsset` than at the `SkeletonRenderer` component at the same GameObject or any parent GameObject. Might be valid setup for special AnimationReferenceAsset re-use for identical skeletons.
  - `SkeletonGraphic` now allows using separate additive Materials despite having `PMA Vertex Colors` enabled (as required for Spine shaders) via the new `Blend Modes` - `Force Additive Material` property in the `Advanced` Inspector section.
  - `SkeletonGraphic` property `CustomSlotMaterials` now properly assigns the override material directly instead of assigning the texture of the override material, which was of little use. Thus you can now assign a `SkeletonGraphic` compatible material like `SkeletonGraphicAdditive-Straight`.
  - `SkeletonGraphicCustomMaterials` now exposes `Custom Slot Materials` property for slot material overrides.
  - Exposed `SpineVisualElement.Initialize` as `public`.
  - `SkeletonRenderer` and `SkeletonGraphic` classes now provide `PhysicsPositionInheritanceLimit` and `PhysicsRotationInheritanceLimit` properties, exposed in the component Inspector under `Physics Inheritance` as `Limit` properties, below `Position` and `Rotation`.

- **Deprecated**

- **Restructuring (Non-Breaking)**
  - Spine Examples have been moved and are now part of the main spine-unity UPM package. To import, select the `spine-unity Runtime` package in the Package Manager window, and in the `Samples` tab and hit `Import`.

### MonoGame

- **Breaking changes**
  - Updated to use new C# runtime with all breaking changes above

## iOS

- **Additions**
  - Added generated slider data `max` APIs.
  - Added generated physics constraint `scaleYMode` APIs.
  - Added generated `Interpolation` and `TrackEntry` mix interpolation APIs.
  - Added convex and inverse clipping support through the updated spine-cpp clipping runtime.

- **Bug fixes**
  - Fixed draw order timelines not mixing out to the setup pose.
  - Fixed bones that don't inherit rotation when parent scale is near zero.
  - Fixed `BonePose.updateLocalTransform(_:)` for `noScale` and `noScaleOrReflection` inheritance.
  - Fixed attachment timelines so hidden setup-pose attachments remain hidden while mixing out, preserving deform behavior.

- **Breaking changes**
  - Removed generated `BonePose.resetWorld(_:)` because resetWorld is an internal implementation detail.
  - Generated SpineSwift attachment loader APIs now receive both the skin `placeholder` and resolved attachment `name`.
  - `AnimationState.getCurrent(_:)` renamed to `AnimationState.getTrack(_:)` in SpineSwift.
  - SpineSwift mesh attachment APIs now use `sourceMesh` naming instead of `parentMesh` to match spine-cpp.
  - SpineSwift attachments now expose `timelineSlots` and `isTimelineActive(...)` to match spine-cpp.
  - SpineSwift IK constraint data now uses `scaleY` instead of the old `uniform` boolean.
  - SpineSwift IK constraint data `scaleY` and `ScaleY` renamed to `scaleYMode` and `ScaleYMode`.

## Dart

- **Additions**
  - Added generated slider data `max` APIs.
  - Added generated physics constraint `scaleYMode` APIs.
  - Added generated `Interpolation` and `TrackEntry` mix interpolation APIs.
  - Added `Slider` and `SliderData` classes for slider constraints
  - Added `SliderTimeline` and `SliderMixTimeline` for animating sliders
  - Added new pose system with `BoneLocal`, `BonePose`, and related classes
  - Added `Pose`, `Posed`, and `PosedActive` base classes for unified pose management

- **Bug fixes**
  - Fixed draw order timelines not mixing out to the setup pose.
  - Fixed bones that don't inherit rotation when parent scale is near zero.
  - Fixed `BonePose.updateLocalTransform()` for `noScale` and `noScaleOrReflection` inheritance.
  - Fixed attachment timelines so hidden setup-pose attachments remain hidden while mixing out, preserving deform behavior.

- **Breaking changes**
  - Removed generated `BonePose.resetWorld()` because resetWorld is an internal implementation detail.
  - Generated Dart attachment loader APIs now receive both the skin `placeholder` and resolved attachment `name`.
  - `AnimationState.getCurrent()` renamed to `AnimationState.getTrack()`.
  - The Dart runtime is now fully auto-generated from the C runtime, maintaining the full C++ type hierarchy with proper nullability annotations
  - `MeshAttachment.parentMesh` is now `MeshAttachment.sourceMesh`, and attachments now expose `timelineSlots` plus `isTimelineActive(...)` to match spine-cpp.
  - All properties are now exposed as getters and setters instead of methods
  - API changes to match C++ naming conventions:
    - `AnimationState.getData()` → `AnimationState.data` (property)
    - `AnimationState.setAnimationByName()` → `AnimationState.setAnimation()`
    - `AnimationState.addAnimationByName()` → `AnimationState.addAnimation()`
    - `AnimationState.getCurrent()` → `AnimationState.getCurrent()`
    - `Skeleton.setSkinByName()` → `Skeleton.setSkin()`
    - `Skeleton.setSkin()` → `Skeleton.setSkin2()`
    - `Skeleton.setToSetupPose()` → `Skeleton.setupPose()`
    - `Skeleton.setBonesToSetupPose()` → `Skeleton.setupPoseBones()`
    - `Skeleton.setSlotsToSetupPose()` → `Skeleton.setupPoseSlots()`
  - Timeline `apply()` methods now take an additional `appliedPose` parameter
  - `EventData` setup payload access moved to `data.setupPose`
  - IK constraint data `scaleY` and `ScaleY` renamed to `scaleYMode` and `ScaleYMode`.

### Flutter

- **Additions**
  - Added generated slider data `max` APIs.
  - Added generated physics constraint `scaleYMode` APIs.
  - Added generated `Interpolation` and `TrackEntry` mix interpolation APIs.
  - Added convex and inverse clipping support through the updated spine-cpp clipping runtime.
  - Added `fromMemory` methods to `AtlasFlutter`, `SkeletonDataFlutter`, `SkeletonDrawableFlutter`, and `SpineWidget` for loading Spine data from custom sources (memory, encrypted storage, databases, custom caching, etc.)
  - Added example `load_from_memory.dart` demonstrating how to load all assets into memory and use the `fromMemory` API

- **Bug fixes**
  - Fixed draw order timelines not mixing out to the setup pose.
  - Fixed bones that don't inherit rotation when parent scale is near zero.
  - Fixed `BonePose.updateLocalTransform()` for `noScale` and `noScaleOrReflection` inheritance.
  - Fixed attachment timelines so hidden setup-pose attachments remain hidden while mixing out, preserving deform behavior.

- **Breaking changes**
  - Removed generated `BonePose.resetWorld()` because resetWorld is an internal implementation detail.
  - `AnimationState.getCurrent()` renamed to `AnimationState.getTrack()`.
  - Generated Flutter attachment loader APIs now receive both the skin `placeholder` and resolved attachment `name`.
  - Generated Flutter mesh attachment APIs now use `sourceMesh` naming instead of `parentMesh` to match spine-cpp.
  - Generated Flutter bindings now expose `Attachment.timelineSlots` and `Attachment.isTimelineActive(...)` to match spine-cpp.
  - Generated Flutter IK constraint data `scaleY` and `ScaleY` renamed to `scaleYMode` and `ScaleYMode`.
  - Updated to use the new auto-generated Dart runtime with all the Dart API changes above
  - Generated Flutter bindings now use `BonePose` for bone setup and unconstrained pose accessors to match spine-cpp.
  - Generated Flutter bindings now expose event setup payloads via `EventData.setupPose` instead of directly on `EventData`.
  - Generated Flutter bindings now construct `Animation` with only a name, and setting timelines also requires the animation's bone indices.
  - Generated Flutter IK constraint data now uses `scaleY` instead of the old `uniform` boolean.

## Haxe

- **Additions**
  - Added `Slider` and `SliderData` classes for slider constraints
  - Added `SliderTimeline` and `SliderMixTimeline` for animating sliders
  - Added new pose system with `BoneLocal`, `BonePose`, and related classes
  - Added `Pose`, `Posed`, and `PosedActive` base classes for unified pose management
  - Added `ConstraintTimeline` interface for unified constraint timeline indexing
  - Added `Animation.getBones()` to get bone indices used by an animation
  - Added `Skeleton` properties `windX`, `windY`, `gravityX`, `gravityY` to allow rotating physics force directions
  - Added `SequenceTimeline` for sequence animation
  - Added `allowMissingRegions` parameter to `AtlasAttachmentLoader` constructor to support skeletons exported with per-skin atlases
  - Linked meshes can now inherit deform and sequence timelines from source meshes in different slots
  - Added `Attachment.timelineSlots` and `Attachment.isTimelineActive()` for attachment timeline propagation across linked meshes
  - Added `DrawOrderFolderTimeline` for animating draw order folders
  - Added `Timeline.additive` and `Timeline.instant` to query timeline blending capabilities
  - Added `TrackEntry.additive` to control additive blending per track entry
  - Added `TrackEntry.mixInterpolation` and `Interpolation` helpers for non-linear AnimationState mixes
  - Ported the latest additive timeline updates and alpha/RGB timeline flicker fixes from spine-libgdx
  - Ported the AnimationState additive/hold rework from spine-libgdx. `MixBlend` and `MixDirection` are no longer used by timelines. The new system uses `fromSetup`, `add`, and `out` parameters and automatically calculates the required hold state values
  - Ported the Skin placeholder name rename from spine-libgdx. `SkinEntry.name` renamed to `placeholderName` to better match Spine editor terminology
  - Ported the sequence attachment refactor from spine-libgdx. `Sequence` now precomputes per-frame regions, UVs, and region offsets, and `RegionAttachment` / `MeshAttachment` now mirror the libgdx implementation
  - Ported the latest clipping runtime changes from spine-libgdx, including convex and inverse clipping support and the inverse clipping crash fix
  - Added `ClippingAttachment.convex` and `ClippingAttachment.inverse`
  - Added `Animation.color` for the animation color as it was in Spine when nonessential data is exported
  - Added `BoneData` icon size and rotation accessors for nonessential editor data
  - Added `ScaleY` enum and `IkConstraintData.scaleY` to control how IK compress/stretch changes `BonePose.scaleY`, including volume preservation
  - Fixed `SkeletonData` default FPS and missing `PathAttachment` initialization
  - BoundsProvider System: added a new flexible BoundsProvider system to improve bounds calculation performance and correctness across all renderers.
    - Added `BoundsProvider` abstract class with interface for calculating skeleton bounding boxes
    - Implemented four concrete `BoundsProvider` classes:
      - `AABBRectangleBoundsProvider` - Uses a simple axis-aligned bounding box rectangle
      - `CurrentPoseBoundsProvider` - Calculates bounds dynamically from the current skeleton pose
      - `SetupPoseBoundsProvider` - Uses setup pose bounds (default implementation)
      - `SkinsAndAnimationBoundsProvider` - Calculates bounds based on specific skins and animations

- **Bug fixes**
  - Fixed attachment timelines so hidden setup-pose attachments remain hidden while mixing out, preserving deform behavior.

- **Breaking changes**
  - `Bone` now extends `PosedActive` with separate pose, constrained, and applied states
  - `Bone` local transform properties moved to `bone.getPose()`:
    ||||
    |--------------------------|-|-----------------------------|
    | bone.x                  |→| bone.getPose().x            |
    | bone.y                  |→| bone.getPose().y            |
    | bone.rotation           |→| bone.getPose().rotation     |
    | bone.scaleX             |→| bone.getPose().scaleX       |
    | bone.scaleY             |→| bone.getPose().scaleY       |
    | bone.shearX             |→| bone.getPose().shearX       |
    | bone.shearY             |→| bone.getPose().shearY       |
  - `Bone` world and applied transform properties moved to `bone.getAppliedPose()`:
    ||||
    |---------------------------|-|-------------------------------------|
    | bone.ax                   |→| bone.getAppliedPose().x            |
    | bone.ay                   |→| bone.getAppliedPose().y            |
    | bone.arotation            |→| bone.getAppliedPose().rotation     |
    | bone.ascaleX              |→| bone.getAppliedPose().scaleX       |
    | bone.ascaleY              |→| bone.getAppliedPose().scaleY       |
    | bone.ashearX              |→| bone.getAppliedPose().shearX       |
    | bone.ashearY              |→| bone.getAppliedPose().shearY       |
    | bone.worldX               |→| bone.getAppliedPose().worldX       |
    | bone.worldY               |→| bone.getAppliedPose().worldY       |
  - `Bone` no longer provides a `skeleton` property, constructor no longer takes a `skeleton` parameter
  - `Slot` properties moved to `slot.getAppliedPose()`:
    ||||
    |---------------------------|-|-------------------------------------|
    | slot.attachment           |→| slot.getAppliedPose().attachment   |
    | slot.deform               |→| slot.getAppliedPose().deform       |
    | slot.sequenceIndex        |→| slot.getAppliedPose().sequenceIndex |
  - `Constraint` properties moved to `constraint.getPose()`:
    ||||
    |----------------------------------|-|----------------------------------------|
    | ikConstraint.mix                |→| ikConstraint.getPose().mix            |
    | ikConstraint.softness           |→| ikConstraint.getPose().softness       |
    | ikConstraint.bendDirection      |→| ikConstraint.getPose().bendDirection  |
    | ikConstraint.compress           |→| ikConstraint.getPose().compress       |
    | ikConstraint.stretch            |→| ikConstraint.getPose().stretch        |

    ||||
    |--------------------------------------|-|---------------------------------------|
    | transformConstraint.mixRotate       |→| transformConstraint.getPose().mixRotate |
    | transformConstraint.mixX            |→| transformConstraint.getPose().mixX    |
    | transformConstraint.mixY            |→| transformConstraint.getPose().mixY    |
    | transformConstraint.mixScaleX       |→| transformConstraint.getPose().mixScaleX |
    | transformConstraint.mixScaleY       |→| transformConstraint.getPose().mixScaleY |
    | transformConstraint.mixShearY       |→| transformConstraint.getPose().mixShearY |

    ||||
    |----------------------------------|-|------------------------------------|
    | pathConstraint.position         |→| pathConstraint.getPose().position |
    | pathConstraint.spacing          |→| pathConstraint.getPose().spacing  |
    | pathConstraint.mixRotate        |→| pathConstraint.getPose().mixRotate |
    | pathConstraint.mixX             |→| pathConstraint.getPose().mixX     |
    | pathConstraint.mixY             |→| pathConstraint.getPose().mixY     |

    ||||
    |--------------------------------------|-|---------------------------------------|
    | physicsConstraint.mix               |→| physicsConstraint.getPose().mix      |
    | physicsConstraint.gravity           |→| physicsConstraint.getPose().gravity  |
    | physicsConstraint.strength          |→| physicsConstraint.getPose().strength |
    | physicsConstraint.damping           |→| physicsConstraint.getPose().damping  |
    | physicsConstraint.massInverse       |→| physicsConstraint.getPose().massInverse |
    | physicsConstraint.wind              |→| physicsConstraint.getPose().wind     |
  - `ConstraintData` properties moved to `constraintData.setup`:
    ||||
    |-----|-|-----|
    | ikConstraintData.mix |→| ikConstraintData.setup.mix |
    | ...| |...|

  - `SkeletonData` now provides a single `ConstraintData` list `constraints` instead of separate lists per constraint type
    ||||
    |-----|-|-----|
    | skeletonData.ikConstraints        |→| Filter skeletonData.constraints for IkConstraintData instances |
    | skeletonData.transformConstraints |→| Filter skeletonData.constraints for TransformConstraintData instances |
    | skeletonData.pathConstraints      |→| Filter skeletonData.constraints for PathConstraintData instances |
    | skeletonData.physicsConstraints   |→| Filter skeletonData.constraints for PhysicsConstraintData instances |
  - `SkeletonData` now provides unified `findConstraint()` method with Class parameter:
    ||||
    |-----|-|-----|
    | skeletonData.findIkConstraint(name)        |→| skeletonData.findConstraint(name, IkConstraintData) |
    | skeletonData.findTransformConstraint(name) |→| skeletonData.findConstraint(name, TransformConstraintData) |
    | skeletonData.findPathConstraint(name)      |→| skeletonData.findConstraint(name, PathConstraintData) |
    | skeletonData.findPhysicsConstraint(name)   |→| skeletonData.findConstraint(name, PhysicsConstraintData) |
  - Renamed setup pose methods:
    ||||
    |-----|-|-----|
    | `Skeleton.setToSetupPose()`       |→| `Skeleton.setupPose()` |
    | `Skeleton.setBonesToSetupPose()`  |→| `Skeleton.setupPoseBones()` |
    | `Skeleton.setSlotsToSetupPose()`  |→| `Skeleton.setupPoseSlots()` |
    | Bone.setToSetupPose()             |→| Bone.setupPose() |
    | Slot.setToSetupPose()             |→| Slot.setupPose() |
    | IkConstraint.setToSetupPose()     |→| IkConstraint.setupPose() |
  - `Physics` enum moved from nested `Skeleton.Physics` to standalone `Physics` class
    - `updateWorldTransform(Skeleton.Physics.update)` → `updateWorldTransform(Physics.update)`
  - Timeline `apply()` methods now take `fromSetup`, `add`, `out`, and `appliedPose` parameters instead of `MixBlend` and `MixDirection`
  - Removed `MixBlend` and `MixDirection`
  - Removed `TrackEntry.holdPrevious` and internal interrupt alpha state. New `AnimationState` hold system automatically calculates the required state values
  - Removed `TrackEntry.mixBlend`. Use `TrackEntry.additive` for additive blending
  - `AnimationState.setCurrent()` renamed to `AnimationState.setTrack()`; `AnimationState.getCurrent()` is deprecated in favor of `AnimationState.getTrack()`
  - Attachment `computeWorldVertices()` methods now take an additional `skeleton` parameter
  - `MeshAttachment.getParentMesh()` / `setParentMesh()` renamed to `getSourceMesh()` / `setSourceMesh()`
  - `RegionAttachment` and `MeshAttachment` now take a non-null `Sequence` in their constructors and use the new sequence attachment model
  - `SkinEntry.name` renamed to `placeholderName` to better match Spine editor terminology
  - `AttachmentLoader` methods now receive both the skin `placeholder` and resolved attachment `name`.
  - `IkConstraintData.uniform` replaced by `IkConstraintData.scaleY`. `IkConstraint.apply()` methods now take `ScaleY` instead of a boolean `uniform` parameter
  - `IkConstraintData.scaleY` and `ScaleY` renamed to `scaleYMode` and `ScaleYMode`.
  - Renamed timeline constraint index methods to use unified `getConstraintIndex()`

### Starling

- **Additions**
  - BoundsProvider Integration
    - Integrated BoundsProvider system into Starling renderer
    - Added `boundsProvider` public field for customizing bounds calculation strategy
    - Added `calculateBounds()` method to recalculate bounds on demand
    - Constructor now accepts optional third parameter `boundsProvider` (defaults to `SetupPoseBoundsProvider`)
    - Simplified `getBounds()` implementation to use `BoundsProvider` instead of direct calculation
  - Added physics position and rotation inheritance settings.
  - Scale Integration
    - Connected `SkeletonSprite.scale`, `scaleX`, and `scaleY` properties to `skeleton.scaleX/scaleY` values
    - Setting scale properties now automatically updates skeleton scale and recalculates bounds
    - Ensures consistent scaling behavior between display object and skeleton

- **Breaking changes**
  - Removed `getAnimationBounds()` method - replace with appropriate `BoundsProvider` implementation or create custom one
  - `hitTest()` now uses `BoundsProvider` using cached bounds from `BoundsProvider` instead of iterating all slots and attachments, for accurate hit testing with animated skeletons, use `CurrentPoseBoundsProvider` and call `calculateBounds()` each frame or on click
  - Changed `_state` to state (public field)
  - Changed `_skeleton` to skeleton (public field)

### Flixel

- **Additions**
  - BoundsProvider Integration
    - Integrated `BoundsProvider` system matching Starling implementation
    - Constructor now accepts optional third parameter `boundsProvider` (defaults to `SetupPoseBoundsProvider`)
    - Added `boundsProvider` public field for customizing bounds calculation strategy
    - Added `calculateBounds()` method to recalculate bounds on demand
    - Added `bounds` property to get the bounds coordinates
  - Added physics position and rotation inheritance settings.
- **Breaking changes**
  - `SkeletonSprite` now extends `FlxTypedGroup<FlxObject>` instead of FlxObject. This was necessary because `FlxObject` bounding/hitbox is always connected to its position and size and cannot be offset
    - This eables proper bounds handling independent of position
    - Added methods and properties to maintain FlxObject-like API despite extending FlxTypedGroup
  - Removed `getAnimationBounds()` method - replace with appropriate `BoundsProvider` implementation
  - Removed `setBoundingBox()` method - use `BoundsProvider` features instead

## Java

- **Additions**
  - Added `Slider` and `SliderData` classes for slider constraints
  - Reworked AnimationState hold system. Replaced `MixBlend`/`MixDirection` in timeline `apply()` with `boolean fromSetup, boolean add, boolean out`. The new bitmask-based hold system prevents dipping during crossfades without requiring `holdPrevious`.
  - Added `Timeline.getAdditive()` and `Timeline.getInstant()` to query timeline blending capabilities.
  - Added `TrackEntry.getAdditive()` / `TrackEntry.setAdditive()` for additive blending per track entry.
  - Renamed `Skin.SkinEntry.getName()` to `getPlaceholderName()`. All `Skin` methods now use `placeholderName` parameter names.

- **Breaking changes (since previous 4.3 beta)**
  - `TrackEntry.getHoldPrevious()` / `setHoldPrevious()` removed.
  - `TrackEntry.getMixBlend()` / `setMixBlend()` removed. Use `TrackEntry.getAdditive()` / `setAdditive()` for additive blending.
  - `MixBlend` and `MixDirection` enums removed from `Animation`.
  - Timeline `apply()` signature changed: `MixBlend blend, MixDirection direction` replaced with `boolean fromSetup, boolean add, boolean out`.
  - `Animation.apply()` signature changed to match.
  - `CurveTimeline1.getRelativeValue()`, `getAbsoluteValue()`, `getScaleValue()` signatures changed.
  - `Skin.SkinEntry.getName()` renamed to `getPlaceholderName()`.
  - Added `SliderTimeline` and `SliderMixTimeline` for animating sliders
  - Added new pose system with `BoneLocal`, `BonePose`, and related classes
  - Added `Pose`, `Posed`, and `PosedActive` base classes for unified pose management
  - Added `ConstraintTimeline` interface for unified constraint timeline indexing
  - Added `Animation.getBones()` to get bone indices used by an animation
  - Added `Skeleton` methods `getGravityX()`, `getGravityY()`, `getWindX()`, `getWindY()` to allow rotating physics force directions
  - Added `SequenceTimeline` for sequence animation
  - Added `allowMissingRegions` parameter to `AtlasAttachmentLoader` constructor to support skeletons exported with per-skin atlases

- **Breaking changes**
  - `Bone` now extends `PosedActive` with separate pose, constrained, and applied states
  - `Bone` local transform methods moved to `bone.getPose()`:
    ||||
    |---------------|-|-------------|
    | bone.getX()             |→| bone.getPose().getX() |
    | bone.getY()             |→| bone.getPose().getY() |
    | bone.getRotation()      |→| bone.getPose().getRotation() |
    | bone.getScaleX()        |→| bone.getPose().getScaleX() |
    | bone.getScaleY()        |→| bone.getPose().getScaleY() |
    | bone.getShearX()        |→| bone.getPose().getShearX() |
    | bone.getShearY()        |→| bone.getPose().getShearY() |
    | bone.setX(value)        |→| bone.getPose().setX(value) |
    | bone.setY(value)        |→| bone.getPose().setY(value) |
    | bone.setRotation(value) |→| bone.getPose().setRotation(value) |
    | bone.setScaleX(value)   |→| bone.getPose().setScaleX(value) |
    | bone.setScaleY(value)   |→| bone.getPose().setScaleY(value) |
    | bone.setShearX(value)   |→| bone.getPose().setShearX(value) |
    | bone.setShearY(value)   |→| bone.getPose().setShearY(value) |
  - `Bone` world and applied transform methods moved to `bone.getAppliedPose()`:
    ||||
    |---------------------|-|--------------------|
    | bone.getAX()             |→| bone.getAppliedPose().getX() |
    | bone.getAY()             |→| bone.getAppliedPose().getY() |
    | bone.getARotation()      |→| bone.getAppliedPose().getRotation() |
    | bone.getAScaleX()        |→| bone.getAppliedPose().getScaleX() |
    | bone.getAScaleY()        |→| bone.getAppliedPose().getScaleY() |
    | bone.getAShearX()        |→| bone.getAppliedPose().getShearX() |
    | bone.getAShearY()        |→| bone.getAppliedPose().getShearY() |
    | bone.getWorldX()         |→| bone.getAppliedPose().getWorldX() |
    | bone.getWorldY()         |→| bone.getAppliedPose().getWorldY() |
    | bone.getWorldRotationX() |→| bone.getAppliedPose().getWorldRotationX() |
    | bone.getWorldRotationY() |→| bone.getAppliedPose().getWorldRotationY() |
  - `Bone` no longer provides a `getSkeleton()` method, constructor no longer takes a `skeleton` parameter
  - `Slot` methods moved to `slot.getAppliedPose()`:
    ||||
    |-----------------------|-|-----------------------------|
    | slot.getAttachment()          |→| slot.getAppliedPose().getAttachment() |
    | slot.setAttachment(value)     |→| slot.getAppliedPose().setAttachment(value) |
    | slot.getDeform()              |→| slot.getAppliedPose().getDeform() |
    | slot.setDeform(value)         |→| slot.getAppliedPose().setDeform(value) |
    | slot.getSequenceIndex()       |→| slot.getAppliedPose().getSequenceIndex() |
    | slot.setSequenceIndex(value)  |→| slot.getAppliedPose().setSequenceIndex(value) |
  - `Constraint` methods moved to `constraint.getPose()`:
    ||||
    |-----------------------------|-|-----------------------|
    | ikConstraint.getMix()                 |→| ikConstraint.getPose().getMix() |
    | ikConstraint.setMix(value)            |→| ikConstraint.getPose().setMix(value) |
    | ikConstraint.getSoftness()            |→| ikConstraint.getPose().getSoftness() |
    | ikConstraint.setSoftness(value)       |→| ikConstraint.getPose().setSoftness(value) |
    | ikConstraint.getBendDirection()       |→| ikConstraint.getPose().getBendDirection() |
    | ikConstraint.setBendDirection(value)  |→| ikConstraint.getPose().setBendDirection(value) |
    | ikConstraint.getCompress()            |→| ikConstraint.getPose().getCompress() |
    | ikConstraint.setCompress(value)       |→| ikConstraint.getPose().setCompress(value) |
    | ikConstraint.getStretch()             |→| ikConstraint.getPose().getStretch() |
    | ikConstraint.setStretch(value)        |→| ikConstraint.getPose().setStretch(value) |

    ||||
    |------------------------------------------|-|--------------------------------------------------|
    | transformConstraint.getMixRotate()      |→| transformConstraint.getPose().getMixRotate()    |
    | transformConstraint.setMixRotate(value) |→| transformConstraint.getPose().setMixRotate(value) |
    | transformConstraint.getMixX()           |→| transformConstraint.getPose().getMixX()         |
    | transformConstraint.setMixX(value)      |→| transformConstraint.getPose().setMixX(value)    |
    | transformConstraint.getMixY()           |→| transformConstraint.getPose().getMixY()         |
    | transformConstraint.setMixY(value)      |→| transformConstraint.getPose().setMixY(value)    |
    | transformConstraint.getMixScaleX()      |→| transformConstraint.getPose().getMixScaleX()    |
    | transformConstraint.setMixScaleX(value) |→| transformConstraint.getPose().setMixScaleX(value) |
    | transformConstraint.getMixScaleY()      |→| transformConstraint.getPose().getMixScaleY()    |
    | transformConstraint.setMixScaleY(value) |→| transformConstraint.getPose().setMixScaleY(value) |
    | transformConstraint.getMixShearY()      |→| transformConstraint.getPose().getMixShearY()    |
    | transformConstraint.setMixShearY(value) |→| transformConstraint.getPose().setMixShearY(value) |

    ||||
    |-------------------------------------|-|-----------------------------------------------|
    | pathConstraint.getPosition()       |→| pathConstraint.getPose().getPosition()       |
    | pathConstraint.setPosition(value)  |→| pathConstraint.getPose().setPosition(value)  |
    | pathConstraint.getSpacing()        |→| pathConstraint.getPose().getSpacing()        |
    | pathConstraint.setSpacing(value)   |→| pathConstraint.getPose().setSpacing(value)   |
    | pathConstraint.getMixRotate()      |→| pathConstraint.getPose().getMixRotate()      |
    | pathConstraint.setMixRotate(value) |→| pathConstraint.getPose().setMixRotate(value) |
    | pathConstraint.getMixX()           |→| pathConstraint.getPose().getMixX()           |
    | pathConstraint.setMixX(value)      |→| pathConstraint.getPose().setMixX(value)      |
    | pathConstraint.getMixY()           |→| pathConstraint.getPose().getMixY()           |
    | pathConstraint.setMixY(value)      |→| pathConstraint.getPose().setMixY(value)      |

    ||||
    |------------------------------------------|-|---------------------------------------------------|
    | physicsConstraint.getMix()              |→| physicsConstraint.getPose().getMix()             |
    | physicsConstraint.setMix(value)         |→| physicsConstraint.getPose().setMix(value)        |
    | physicsConstraint.getGravity()          |→| physicsConstraint.getPose().getGravity()         |
    | physicsConstraint.setGravity(value)     |→| physicsConstraint.getPose().setGravity(value)    |
    | physicsConstraint.getStrength()         |→| physicsConstraint.getPose().getStrength()        |
    | physicsConstraint.setStrength(value)    |→| physicsConstraint.getPose().setStrength(value)   |
    | physicsConstraint.getDamping()          |→| physicsConstraint.getPose().getDamping()         |
    | physicsConstraint.setDamping(value)     |→| physicsConstraint.getPose().setDamping(value)    |
    | physicsConstraint.getMassInverse()      |→| physicsConstraint.getPose().getMassInverse()     |
    | physicsConstraint.setMassInverse(value) |→| physicsConstraint.getPose().setMassInverse(value) |
    | physicsConstraint.getWind()             |→| physicsConstraint.getPose().getWind()            |
    | physicsConstraint.setWind(value)        |→| physicsConstraint.getPose().setWind(value)       |
  - `ConstraintData` methods moved to `constraintData.getSetupPose()`:
    ||||
    |-----|-|-----|
    | ikConstraintData.getMix() |→| ikConstraintData.getSetupPose().getMix() |
    | ...| |...|

  - `SkeletonData` now provides a single `ConstraintData` list `getConstraints()` instead of separate lists per constraint type
    ||||
    |-----|-|-----|
    | SkeletonData.getIkConstraints()        |→| Filter SkeletonData.getConstraints() for IkConstraintData instances |
    | SkeletonData.getTransformConstraints() |→| Filter SkeletonData.getConstraints() for TransformConstraintData instances |
    | SkeletonData.getPathConstraints()      |→| Filter SkeletonData.getConstraints() for PathConstraintData instances |
    | SkeletonData.getPhysicsConstraints()   |→| Filter SkeletonData.getConstraints() for PhysicsConstraintData instances |
  - `SkeletonData` now provides unified `findConstraint()` method with Class parameter:
    ||||
    |-----|-|-----|
    | SkeletonData.findIkConstraint(name)        |→| SkeletonData.findConstraint(name, IkConstraintData.class) |
    | SkeletonData.findTransformConstraint(name) |→| SkeletonData.findConstraint(name, TransformConstraintData.class) |
    | SkeletonData.findPathConstraint(name)      |→| SkeletonData.findConstraint(name, PathConstraintData.class) |
    | SkeletonData.findPhysicsConstraint(name)   |→| SkeletonData.findConstraint(name, PhysicsConstraintData.class) |
  - Renamed setup pose methods:
    ||||
    |-----|-|-----|
    | `Skeleton.setToSetupPose()`      |→| `Skeleton.setupPose()` |
    | `Skeleton.setBonesToSetupPose()` |→| `Skeleton.setupPoseBones()` |
    | `Skeleton.setSlotsToSetupPose()` |→| `Skeleton.setupPoseSlots()` |
    | Bone.setToSetupPose()            |→| Bone.setupPose() |
    | Slot.setToSetupPose()            |→| Slot.setupPose() |
    | IkConstraint.setToSetupPose()    |→| IkConstraint.setupPose() |
  - `Physics` enum moved from nested `Skeleton.Physics` to standalone class `Physics`
    - `updateWorldTransform(Skeleton.Physics.update)` → `updateWorldTransform(Physics.update)`
  - Timeline `apply()` methods now take an additional `appliedPose` parameter
  - Attachment `computeWorldVertices()` methods now take an additional `skeleton` parameter
  - Renamed timeline constraint index methods to use unified `getConstraintIndex()`
  - Reorganized timeline class hierarchy with `BoneTimeline1`, `BoneTimeline2`, and `SlotCurveTimeline` base classes

### libGDX

- **Breaking changes**
  - Updated to use new pose system from Java runtime

- **Bug fixes**
  - Updated the Gradle wrapper and fixed the headless test fat jar task to build included libgdx runtime classpath artifacts before packaging.
  - Gradle builds now delete stale Eclipse `bin/` output before compiling so removed classes don't linger on Java headless test classpaths.
  - Updated the libGDX dependency from `1.14.1-SNAPSHOT` to the released `1.14.1`.

### Android

- **Breaking changes**
  - Updated to use new Java runtime with all breaking changes above

- **Bug fixes**
  - Updated the Android atlas attachment loader to match the current `AttachmentLoader` method signatures.
  - Updated the Android examples to use `AnimationState.getTrack()` instead of the removed `getCurrent()` API.
  - Updated the libGDX dependency from `1.14.1-SNAPSHOT` to the released `1.14.1`.

## Swift

- **Additions**
  - Added `Slider` and `SliderData` classes for slider constraints
  - Added `SliderTimeline` and `SliderMixTimeline` for animating sliders
  - Added new pose system with `BoneLocal`, `BonePose`, and related classes
  - Added `Pose`, `Posed`, and `PosedActive` base classes for unified pose management

- **Breaking changes**
  - The Swift runtime is now fully auto-generated from the C runtime, maintaining the full C++ type hierarchy with proper nullability annotations
  - All properties are now exposed as getters and setters instead of methods
  - Event setup payloads now live on `EventData.setupPose` instead of directly on `EventData`
  - API changes to match C++ naming conventions:
    - `AnimationState.setAnimationByName()` → `AnimationState.setAnimation()`
    - `AnimationState.addAnimationByName()` → `AnimationState.addAnimation()`
    - `AnimationState.getCurrent()` → `AnimationState.getCurrent()`
    - `Skeleton.findSlot(slotName:)` → `Skeleton.findSlot()`
    - `Skeleton.setToSetupPose()` → `Skeleton.setupPose()`
    - `Skeleton.setBonesToSetupPose()` → `Skeleton.setupPoseBones()`
    - `Skeleton.setSlotsToSetupPose()` → `Skeleton.setupPoseSlots()`
  - Timeline `apply()` methods now take an additional `appliedPose` parameter

### iOS

- **Breaking changes**
  - Updated to use the new auto-generated Swift runtime with all the Swift API changes above
  - Generated Swift bindings now use `BonePose` for bone setup and unconstrained pose accessors to match spine-cpp.
  - Generated Swift bindings now expose event setup payloads via `EventData.setupPose` instead of directly on `EventData`.
  - Generated Swift bindings now construct `Animation` with only a name, and setting timelines also requires the animation's bone indices.

## TypeScript/JavaScript

- **Additions**
  - Added `Slider` and `SliderData` classes for slider constraints
  - Added `SliderTimeline` and `SliderMixTimeline` for animating sliders
  - Added new pose system with `BoneLocal`, `BonePose`, and related classes
  - Added `Pose`, `Posed`, and `PosedActive` base classes for unified pose management
  - Added `ConstraintTimeline` interface for unified constraint timeline indexing
  - Added `Animation.getBones()` to get bone indices used by an animation
  - Added `Skeleton` properties `windX`, `windY`, `gravityX`, `gravityY` to allow rotating physics force directions
  - Added `SequenceTimeline` for sequence animation
  - Added `allowMissingRegions` parameter to `AtlasAttachmentLoader` constructor to support skeletons exported with per-skin atlases
  - Added `TextureLoader` type with optional `pma?: boolean` parameter to `AssetManagerBase`. `AssetManagerBase` now tracks and passes PMA metadata from atlas pages to texture loaders, allowing runtimes to automatically premultiply textures on upload
  - Added `SkeletonRendererCore` class to reduce complexity of runtime-specific render code
  - Linked meshes can now inherit deform and sequence timelines from source meshes in different slots
  - Added `Attachment.timelineSlots` and `Attachment.isTimelineActive()` for attachment timeline propagation across linked meshes
  - Added `DrawOrderFolderTimeline` for animating draw order folders
  - Added `Timeline.additive` and `Timeline.instant` to query timeline blending capabilities
  - Added `TrackEntry.additive` to control additive blending per track entry
  - Added `TrackEntry.mixInterpolation` and `Interpolation` helpers for non-linear AnimationState mixes
  - Added support for passing `null` as the attachment name to `Skeleton.setAttachment()`
  - Ported the latest parser fixes from spine-libgdx, including the 4.3 path constraint flag fix and the weighted mesh binary vertex allocation/count fix
  - Ported the latest additive timeline updates and alpha/RGB timeline flicker fixes from spine-libgdx
  - Ported the AnimationState additive/hold rework from spine-libgdx. `MixBlend` and `MixDirection` are no longer used by timelines. The new system uses `fromSetup`, `add`, and `out` parameters and automatically calculates the required hold state values
  - Ported the Skin placeholder name rename from spine-libgdx. `SkinEntry.name` renamed to `placeholderName` to better match Spine editor terminology
  - Ported the sequence attachment refactor from spine-libgdx. `Sequence` now precomputes per-frame regions, UVs, and region offsets, and `RegionAttachment` / `MeshAttachment` now mirror the libgdx implementation
  - Ported the latest clipping runtime changes from spine-libgdx, including convex and inverse clipping support and the inverse clipping crash fix
  - Added `ClippingAttachment.convex` and `ClippingAttachment.inverse`
  - Added `Animation.color` for the animation color as it was in Spine when nonessential data is exported
  - Added `BoneData` icon size and rotation accessors for nonessential editor data
  - Added `ScaleY` enum and `IkConstraintData.scaleY` to control how IK compress/stretch changes `BonePose.scaleY`, including volume preservation
  - Fixed `SkeletonData` default FPS and missing `PathAttachment` initialization
  - Fixed reverse IK bend positive logic and transform constraint/slider scaling issues

- **Bug fixes**
  - Fixed attachment timelines so hidden setup-pose attachments remain hidden while mixing out, preserving deform behavior.

- **Breaking changes**
  - `Bone` now extends `PosedActive` with separate pose, constrained, and applied states
  - `Bone` local transform properties moved to `bone.getPose()`:
    ||||
    |-------------------------|-|-----------------------------|
    | bone.x                  |→| bone.getPose().x            |
    | bone.y                  |→| bone.getPose().y            |
    | bone.rotation           |→| bone.getPose().rotation     |
    | bone.scaleX             |→| bone.getPose().scaleX       |
    | bone.scaleY             |→| bone.getPose().scaleY       |
    | bone.shearX             |→| bone.getPose().shearX       |
    | bone.shearY             |→| bone.getPose().shearY       |
  - `Bone` world and applied transform properties moved to `bone.getAppliedPose()`:
    ||||
    |---------------------------|-|-------------------------------------|
    | bone.ax                   |→| bone.getAppliedPose().x            |
    | bone.ay                   |→| bone.getAppliedPose().y            |
    | bone.arotation            |→| bone.getAppliedPose().rotation     |
    | bone.ascaleX              |→| bone.getAppliedPose().scaleX       |
    | bone.ascaleY              |→| bone.getAppliedPose().scaleY       |
    | bone.ashearX              |→| bone.getAppliedPose().shearX       |
    | bone.ashearY              |→| bone.getAppliedPose().shearY       |
    | bone.worldX               |→| bone.getAppliedPose().worldX       |
    | bone.worldY               |→| bone.getAppliedPose().worldY       |
  - `Bone` no longer provides a `skeleton` property, constructor no longer takes a `skeleton` parameter
  - `Slot` properties moved to `slot.getAppliedPose()`:
    ||||
    |---------------------------|-|-------------------------------------|
    | slot.attachment           |→| slot.getAppliedPose().attachment   |
    | slot.deform               |→| slot.getAppliedPose().deform       |
    | slot.sequenceIndex        |→| slot.getAppliedPose().sequenceIndex |
  - `Constraint` properties moved to `constraint.getPose()`:
    ||||
    |---------------------------------|-|----------------------------------------|
    | ikConstraint.mix                |→| ikConstraint.getPose().mix            |
    | ikConstraint.softness           |→| ikConstraint.getPose().softness       |
    | ikConstraint.bendDirection      |→| ikConstraint.getPose().bendDirection  |
    | ikConstraint.compress           |→| ikConstraint.getPose().compress       |
    | ikConstraint.stretch            |→| ikConstraint.getPose().stretch        |

    ||||
    |-------------------------------------|-|---------------------------------------|
    | transformConstraint.mixRotate       |→| transformConstraint.getPose().mixRotate |
    | transformConstraint.mixX            |→| transformConstraint.getPose().mixX    |
    | transformConstraint.mixY            |→| transformConstraint.getPose().mixY    |
    | transformConstraint.mixScaleX       |→| transformConstraint.getPose().mixScaleX |
    | transformConstraint.mixScaleY       |→| transformConstraint.getPose().mixScaleY |
    | transformConstraint.mixShearY       |→| transformConstraint.getPose().mixShearY |

    ||||
    |---------------------------------|-|------------------------------------|
    | pathConstraint.position         |→| pathConstraint.getPose().position |
    | pathConstraint.spacing          |→| pathConstraint.getPose().spacing  |
    | pathConstraint.mixRotate        |→| pathConstraint.getPose().mixRotate |
    | pathConstraint.mixX             |→| pathConstraint.getPose().mixX     |
    | pathConstraint.mixY             |→| pathConstraint.getPose().mixY     |

    ||||
    |-------------------------------------|-|---------------------------------------|
    | physicsConstraint.mix               |→| physicsConstraint.getPose().mix      |
    | physicsConstraint.gravity           |→| physicsConstraint.getPose().gravity  |
    | physicsConstraint.strength          |→| physicsConstraint.getPose().strength |
    | physicsConstraint.damping           |→| physicsConstraint.getPose().damping  |
    | physicsConstraint.massInverse       |→| physicsConstraint.getPose().massInverse |
    | physicsConstraint.wind              |→| physicsConstraint.getPose().wind     |
  - `ConstraintData` properties moved to `constraintData.setupPose`:
    ||||
    |-----|-|-----|
    | ikConstraintData.mix |→| ikConstraintData.setupPose.mix |
    | ...| |...|

  - `SkeletonData` now provides a single `ConstraintData` list `constraints` instead of separate lists per constraint type
    ||||
    |-----|-|-----|
    | skeletonData.ikConstraints        |→| Filter skeletonData.constraints for IkConstraintData instances |
    | skeletonData.transformConstraints |→| Filter skeletonData.constraints for TransformConstraintData instances |
    | skeletonData.pathConstraints      |→| Filter skeletonData.constraints for PathConstraintData instances |
    | skeletonData.physicsConstraints   |→| Filter skeletonData.constraints for PhysicsConstraintData instances |
  - `SkeletonData` now provides unified `findConstraint()` method with type constructor parameter:
    ||||
    |-----|-|-----|
    | skeletonData.findIkConstraint(name)        |→| skeletonData.findConstraint(name, IkConstraintData) |
    | skeletonData.findTransformConstraint(name) |→| skeletonData.findConstraint(name, TransformConstraintData) |
    | skeletonData.findPathConstraint(name)      |→| skeletonData.findConstraint(name, PathConstraintData) |
    | skeletonData.findPhysicsConstraint(name)   |→| skeletonData.findConstraint(name, PhysicsConstraintData) |
  - Renamed setup pose methods:
    ||||
    |-----|-|-----|
    | `Skeleton.setToSetupPose()`       |→| `Skeleton.setupPose()` |
    | `Skeleton.setBonesToSetupPose()`  |→| `Skeleton.setupPoseBones()` |
    | `Skeleton.setSlotsToSetupPose()`  |→| `Skeleton.setupPoseSlots()` |
    | Bone.setToSetupPose()             |→| Bone.setupPose() |
    | Slot.setToSetupPose()             |→| Slot.setupPose() |
    | IkConstraint.setToSetupPose()     |→| IkConstraint.setupPose() |
  - `Physics` enum moved from nested `Skeleton.Physics` to standalone `Physics` export
    - `updateWorldTransform(Skeleton.Physics.update)` → `updateWorldTransform(Physics.update)`
  - Timeline `apply()` methods now take `fromSetup`, `add`, `out`, and `appliedPose` parameters instead of `MixBlend` and `MixDirection`
  - Removed `MixBlend` and `MixDirection`
  - Removed `TrackEntry.holdPrevious` and internal interrupt alpha state. New `AnimationState` hold system automatically calculates the required state values
  - Removed `TrackEntry.mixBlend`. Use `TrackEntry.additive` for additive blending
  - `AnimationState.setCurrent()` renamed to `AnimationState.setTrack()`; `AnimationState.getCurrent()` is deprecated in favor of `AnimationState.getTrack()`
  - Attachment `computeWorldVertices()` methods now take an additional `skeleton` parameter
  - `MeshAttachment.getParentMesh()` / `setParentMesh()` renamed to `getSourceMesh()` / `setSourceMesh()`
  - `RegionAttachment` and `MeshAttachment` now take a non-null `Sequence` in their constructors and use the new sequence attachment model
  - `EventData` no longer stores `intValue`, `floatValue`, `stringValue`, `volume`, and `balance` directly. Use `eventData.setupPose` to access the setup pose `Event` which provides these properties instead
  - `SkinEntry.name` renamed to `placeholderName` to better match Spine editor terminology
  - `AttachmentLoader` methods now receive both the skin `placeholder` and resolved attachment `name`.
  - `IkConstraintData.uniform` replaced by `IkConstraintData.scaleY`. `IkConstraint.apply()` methods now take `ScaleY` instead of a boolean `uniform` parameter
  - `IkConstraintData.scaleY` and `ScaleY` renamed to `scaleYMode` and `ScaleYMode`.
  - Renamed timeline constraint index methods to use unified `getConstraintIndex()`
  - API changes to match reference runtime naming conventions:
    - `addAnimationWith()` → `addAnimation()`
    - `setAnimationWith()` → `setAnimation()`
    - `setMixWith()` → `setMix()`
    - `setSkinByName()` → `setSkin()`
    - `getAttachmentByName()` → `getAttachment()`

### WebGL backend

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime
  - `GLTexture` constructor now requires `pma: boolean` parameter (automatically read from atlas page metadata)
  - Removed `GLTexture.DISABLE_UNPACK_PREMULTIPLIED_ALPHA_WEBGL` static property
  - `SkeletonRenderer` and `SkeletonDebugRenderer` no longer have `premultipliedAlpha` property - PMA is handled automatically
  - `SceneRenderer.drawSkeleton()` and `drawSkeletonDebug()` no longer take `premultipliedAlpha` parameter
  - `PolygonBatcher.setBlendMode()` no longer takes `premultipliedAlpha` parameter
  - `LoadingScreen` no longer accepts PMA parameters

### Canvas backend

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime

### CanvasKit backend

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime
  - Simplified rendering implementation

### Three.js backend

- **Additions**
  - Added a React Three Fiber example for using `SkeletonMesh` with R3F's `<primitive />` and `useFrame`
  - Added support for Three.js versions from `0.162.0` up to `0.184.x`
  - Added physics position and rotation inheritance settings.

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime
  - `AssetManager` constructor no longer takes `pma` parameter - PMA is handled automatically

### Player

- **Additions**
  - Added support for multiple skins in the skin selector
  - Added `debug` support as a boolean option

- **Fixes**
  - Fixed resize mode regressions
  - The progress bar is now shown only when hovering the bottom bar and can be dragged outside its area

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime
  - Removed `premultipliedAlpha` option from `SpinePlayerConfig` - PMA is now handled automatically

### Pixi v7

- **Additions**
  - Added static `createOptions` method for Spine initialization config to simplify subclassing
  - Added `allowMissingRegions` parameter to game object factory
  - Added physics position and rotation inheritance settings.

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime
  - Deprecated `from()` method in favor of constructor accepting both `SpineOptions` and `SpineFromOptions`
  - Removed deprecated methods

### Pixi v8

- **Additions**
  - Added static `createOptions` method for Spine initialization config to simplify subclassing
  - Added `allowMissingRegions` parameter to game object factory
  - Added physics position and rotation inheritance settings.
  - Restored control bones example

- **Fixes**
  - Fixed clipping regressions

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime
  - Deprecated `from()` method in favor of constructor accepting both `SpineOptions` and `SpineFromOptions`

### Phaser v3

- **Additions**
  - Added physics position and rotation inheritance settings.

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime
  - `SpinePlugin.spineAtlas()` loader no longer takes `premultipliedAlpha` parameter - PMA is handled automatically
  - `SpinePlugin.createSkeleton()` no longer takes `premultipliedAlpha` parameter

### Phaser v4

- **Additions**
  - Added physics position and rotation inheritance settings.

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime
  - `SpinePlugin.spineAtlas()` loader no longer takes `premultipliedAlpha` parameter - PMA is handled automatically
  - `SpinePlugin.createSkeleton()` no longer takes `premultipliedAlpha` parameter

### Web Components

- **Breaking changes**
  - Updated to use new TypeScript/JavaScript runtime
  - Updated skeleton and overlay component implementations
  - Removed `pma` property from `SpineWebComponentSkeleton` - PMA is handled automatically

# 4.2

## C

- **Additions**
  - Added physics support
    - Added `spPhysicsConstraintTimeline` and `spPhysicsConstraintResetTimeline`
    - Added `spPhysics` to be passed to `spSkeleton_updateWorldTransform()`
    - Added `spSkeletonData_findPhysicsConstraint()` to query a physics constraint by name
    - Added `spSkeleton_findPhysicsConstraint()` to query a physics constraint by name
    - Added `spSkeleton_physicsTranslate()` to translate all physics constraints by some distances in the skeleton coordinate system
    - Added `spSkeleton_physicsRotate()` to rotate all physics constraints by some distances in the skeleton coordinate system
    - Added `spSkeleton::time` to keep track of time for physics simulations
    - See also breaking changes for `spSkeleton_updateWorldTransform()` and the requirement to call `spSkeleton_update()` to advance
      pyhsics each frame.
  - Added `spInheritTimeline`
  - Added [`spTrackEntry::alphaAttachmentThreshold`](http://esotericsoftware.com/spine-api-reference#TrackEntry-alphaAttachmentThreshold)
  - Removed `const` qualifiers where appropriate
  - Added `spTrackEntry_setMixDuration()` to set the mix duration in conjunction with a delay
  - Added `spTrackEntry_wasApplied()` to check if the entry has been applied
  - Added `spBone_worldToParent()` to transform coordinates from world space to the parent space of a bone
  - Added `spBone_localToParent()` to transform coordinates from a bone's local space to its parent space
  - Added non essential fields `icon` and `visible` to `spBoneData`
  - Added non essential fields `path` and `visible` to `spSlotData`
- **Breaking changes**
  - Renamed `spTrackEntry::attachmentThreshold` to `spTrackEntry::mixAttachmentThreshold`
  - Renamed `spTrackEntry::drawOrderThreshold` to `spTrackEntry::mixDrawOrdertThreshold`
  - Renamed `spTransformMode` to `spInherit` and all `SP_TRANSFORMMODE_*` enums to `SP_INHERIT_*`
  - Changed `spMeshAttachment::edges` from `int *` to `unsigned short *`
  - You must call `spSkeleton_update(delta)` before calling `spSkeleton_updateWorldTransform()` if the frame time has advanced. This is needed to update physics accordingly
  - `spSkeleton_updateWorldTransform()` takes an additional `spPhysics` parameter. See the `spPhysics` documentation for information on what the different enum values do

### SFML

- Added physics examples
- `SkeletonDrawable::update()` now takes an additional `spPhysics physics` parameter that specifies how physics should be updated

### SDL

- `spSkeletonDrawable_update()` now takes an additional `spPhysics physics` parameter that specifies how physics should be updated

## C++

- Added physics support
  - Added `PhysicsConstraintXXXTimeline` and `PhysicsConstraintResetTimeline`
  - Added `Physics` to be passed to `Skeleton::updateWorldTransform()`
  - Added `SkeletonData::findPhysicsConstraint()` and `SkeletonData::getPhysicsConstraints()` to query physics constraints
  - Added `Skeleton::findPhysicsConstraint()` and `Skeleton::getPhysicsConstraints()` to query physics constraints
  - Added `Skeleton::physicsTranslate()` to translate all physics constraints by some distances in the skeleton coordinate system
  - Added `Skeleton::physicsRotate()` to rotate all physics constraints by some distances in the skeleton coordinate system
  - Added `Skeleton::time` to keep track of time for physics simulations
  - See also breaking changes for `Skeleton::updateWorldTransform()` and the requirement to call `Skeleton::update()` to advance
    pyhsics each frame.
- Added `InheritTimeline`
- Added [`TrackEntry::_alphaAttachmentThreshold`](http://esotericsoftware.com/spine-api-reference#TrackEntry-alphaAttachmentThreshold)
- Added `TrackEntry::setMixDuration()` to set the mix duration in conjunction with a delay
- Added `TrackEntry::wasApplied()` to check if the entry has been applied
- Added `Bone::worldToParent()` to transform coordinates from world space to the parent space of a bone
- Added `Bone::localToParent()` to transform coordinates from a bone's local space to its parent space
- Added non essential fields `icon` and `visible` to `BoneData`
- Added non essential fields `path` and `visible` to `SlotData`
- Added `setToSetupPose()` to all contraint classes
- **Breaking changes**
  - Renamed `TrackEntry::attachmentThreshold` to `TrackEntry::mixAttachmentThreshold`
  - Renamed `TrackEntry::drawOrderThreshold` to `TrackEntry::mixDrawOrdertThreshold`
  - Renamed `TransformMode` to `Inherit` and all `TransformMode_*` enums to `Inherit_*`
  - You must call `Skeleton::update(delta)` before calling `Skeleton::updateWorldTransform()` if the frame time has advanced. This is needed to update physics accordingly
  - `Skeleton::updateWorldTransform()` takes an additional `Physics` parameter. See the `Physics` documentation for information on what the different enum values do
  - All `Updatable` sub-classes like `Bone` and constraints now take an additional `Physics` parameter for their `update()` methods

### Cocos2d-x

- Added physics example
- Improved build system and build documentation

### SFML

- `SkeletonDrawable::update()` now takes an additional `Physics physics` parameter that specifies how physics should be updated

### SDL

- `SkeletonDrawable::update()` now takes an additional `Physics physics` parameter that specifies how physics should be updated

### UE4

- **Breaking**: Renamed runtime folder from `spine-ue4` to `spine-ue`
- **Breaking**: Renamed plugin `SpinePlugin`. You must update your project's `Build.cs` file accordingly
- **Breaking**: Starting with Unreal Engine 5.3 imported `.skel`/`.json` and `.atlas` files in the same folder must NOT have a common prefix. E.g. `skeleton.json` and `skeleton.atlas` will not work. Make sure to rename at least one of the two files so there is no prefix collision, e.g. `skeleton-data.json` and `skeleton.atlas`.
- Added compatibility with UE 5.3
- Added more example maps
- Added blueprint-callable methods `PhysicsTranslate()`, `PhysicsRotate()` and `ResetPhysicsConstraints()` (which will reset all physics constraints in the skeleton) to `SpineSkeletonComponent` and `SpineWidget`.

### Godot

- **Breaking**: Renamed `TrackEntry.set_attachment_threshold` and `TrackEntry.get_attachment_threshold` to `TrackEntry.set_mix_attachment_threshold` and `TrackEntry.get_mix_attachment_threshold`
- **Breaking**: Renamed `TrackEntry.set_draw_order_threshold` and `TrackEntry.get_draw_order_threshold` to `TrackEntry.set_mix_draw_order_threshold` and `TrackEntry.get_mix_draw_order_threshold`
- **BReaking**: `SpineSkeleton.update_world_transform` takes an additional `physics` parameter that specifies how physics should be updated
- Added compatibility for Godot 4.1, 4.2 and C#, see builds at [https://esotericsoftware.com/spine-godot](https://esotericsoftware.com/spine-godot)
- Added physics examples
- Added `SpineBone.world_to_parent` to transform coordinates from world space to the parent space of a bone
- Added `SpineBone.local_to_parent` to transform coordinates from a bone's local space to its parent space
- Physics support
  - Added `SpineBone.get_inherit`/`SpineBone.set_inherit`
  - Added `SpinePhysicsConstraint` and `SpinePhysicsConstraintData`
  - Added `SpineSkeleton.update()` to advance the physics time
  - ADded `SpineSkeleton.get_time`/`SpineSkeleton.set_time` to access the physics time
  - Added `SpineSkeleton.physics_translate()` to translate all physics constraints by some distances in the skeleton coordinate system
  - Added `SpineSkeleton.physics_rotate()` to rotate all physics constraints by some distances in the skeleton coordinate system
  - Added `SpineSkeleotnDataResource.set_reference_scale`/`SpineSkeletonDataResource.get_reference_scale` to access the reference scale of the loaded skeleton data
- Added [`TrackEntry.set_alpha_attachment_threshold`](http://esotericsoftware.com/spine-api-reference#TrackEntry-alphaAttachmentThreshold)
- Added `TrackEntry.set_mix_duration_and_delay()` to set the mix duration in conjunction with a delay
- Added `TrackEntry::was_applied()` to check if the entry has been applied

## C#

- **Additions**

  - Added [`TrackEntry.AlphaAttachmentThreshold`](http://esotericsoftware.com/spine-api-reference#TrackEntry-alphaAttachmentThreshold).

- **Breaking changes**
  - Renamed `TrackEntry` `AttachmentThreshold` to `MixAttachmentThreshold`, renamed `DrawOrderThreshold` to `MixDrawOrderThreshold`.
  - Changed signature of `Skeleton.UpdateWorldTransform()` to `UpdateWorldTransform(Skeleton.Physics physics)`. The default replacement for `skeleton.UpdateWorldTransform()` calls is `skeleton.UpdateWorldTransform(Skeleton.Physics.Update)`. If you are certain that a subsequent call to `skeleton.UpdateWorldTransform(Skeleton.Physics.Update)` follows in the same frame, you can pass `Skeleton.Physics.Pose` as argument instead of `Skeleton.Physics.Update`.

### Unity

- **Officially supported Unity versions are 2017.1-6000.1**.

- **Additions**

  - `OnPostProcessVertices` callback parameter `MeshGeneratorBuffers` now provides access to `uv2Buffer` and `uv3Buffer` properties of `MeshGenerator`, automatically allocating buffers upon access if `tintBlack` is disabled. This allows for passing own vertex data to a shader on second and third uv channels.
  - Added `Spine/SkeletonGraphic Grayscale` shader to provide a basic grayscale shader for SkeletonGraphic as well. SkeletonGraphic Material `SkeletonGraphicDefaultGrayscale` uses this shader and can be assigned at `SkeletonGraphic` components as usual.
  - `SkeletonGraphic` now supports automatic scaling based on its `RectTransform` bounds. Automatic scaling can be enabled by setting the added `Layout Scale Mode` Inspector property to either `Width Controls Height`, `Height Controls Width`, `FitInParent` or `EnvelopeParent`. It is set to `None` by default to keep previous behaviour and avoid breaking existing projects. To modify the reference layout bounds, hit the additional `Edit Layout Bounds` toggle button to switch into edit mode, adjust the bounds or hit `Match RectTransform with Mesh`, and hit the button again when done adjusting. The skeleton will now be scaled accordingly to fit the reference layout bounds to the object's `RectTransform`.
  - Added previously missing unlit URP 2D shader variant, available under `Universal Render Pipeline/2D/Spine/Skeleton`.
  - Added support for light cookies at `Universal Render Pipeline/Spine/Sprite` shader.
  - Timeline extension package: An additional Spine preferences parameter `Timeline` - `Default Mix Duration` has been added, setting newly added `SpineAnimationStateClip` clips accordingly, defaults to false. This Spine preferences parameter can be enabled to default to the previous behaviour before this update.
  - Tint Black: Added support for [Tint Black](http://en.esotericsoftware.com/spine-slots#Tint-black) functionality at all Spine URP shaders (2D and 3D shaders) and at all standard pipeline `Spine/Sprite` shaders. This feature can be enabled via the `Tint Black` material parameter in the Inspector. Note: The URP Sprite shaders provided in the Spine URP Shaders extension UPM package require the latest version of the spine-unity runtime (package version 4.1.12, 2023-05-31 or newer) to display the added material parameters in the Inspector GUI.
  - Added `SkeletonGraphic.MeshScale` property to allow access to calculated mesh scale. `MeshScale` is based on (1) Canvas pixels per unit, and (2) `RectTransform` bounds when using `Layout Scale Mode` other than `None` at `SkeletonGraphic` which scales the skeleton mesh to fit the parent `RectTransform` bounds accordingly.
  - Added `updateSeparatorPartScale` property to `SkeletonGraphic` to let render separator parts follow the scale (lossy scale) of the `SkeletonGraphic` GameObject. Defaults to `false` to maintain existing behaviour.
  - Added experimental `EditorSkeletonPlayer` component to allow Editor playback of the initial animation set at `SkeletonAnimation` or `SkeletonGraphic` components. Add this component to your skeleton GameObject to enable the in-editor animation preview. Allows configurations for continuous playback when selected, deselected, and alternative single-frame preview by setting `Fixed Track Time` to any value other than 0. Limitations: At skeletons with variable material count the Inspector preview may be too unresponsive. It is then recommended to disable the `EditorSkeletonPlayer` component (at the top of the Inspector) to make it responsive again, then you can disable `Play When Selected` and re-enable the component to preview playback only when deselected.
  - Added example component `RenderCombinedMesh` to render a combined mesh of multiple meshes or submeshes. This is required by `OutlineOnly` shaders to render a combined outline when using `SkeletonRenderSeparator` or multiple atlas pages which would normally lead to outlines around individual parts. To add a combined outline to your SkeletenRenderer:
    1. Add a child GameObject and move it a bit back (e.g. position Z = 0.01).
    2. Add a `RenderCombinedMesh` component, provided in the `Spine Examples/Scripts/Sample Components` directory.
    3. Copy the original material, add _\_Outline_ to its name and set the shader to your outline-only shader like `Universal Render Pipeline/Spine/Outline/Skeleton-OutlineOnly` or `Spine/Outline/OutlineOnly-ZWrite`.
    4. Assign this _\_Outline_ material at the new child GameObject's `MeshRenderer` component.
       If you are using `SkeletonRenderSeparator` and need to enable and disable the `SkeletonRenderSeparator` component at runtime, you can increase the `RenderCombinedMesh` `Reference Renderers` array by one and assign the `SkeletonRenderer` itself at the last entry after the parts renderers. Disabled `MeshRenderer` components will be skipped when combining the final mesh, so the combined mesh is automatically filled from the desired active renderers.
  - Timeline extension package: Added static `EditorEvent` callback to allow editor scripts to react to animation events outside of play-mode. Register to the events via `Spine.Unity.Playables.SpineAnimationStateMixerBehaviour.EditorEvent += YourCallback;`.
  - URP Shaders: Added `Depth Write` property to shaders `Universal Render Pipeline/Spine/Skeleton` and `Universal Render Pipeline/Spine/Skeleton Lit`. Defaults to false to maintain existing behaviour.
  - Added `Animation Update` mode (called `UpdateTiming` in code) `In Late Update` for `SkeletonAnimation`, `SkeletonMecanim` and `SkeletonGraphic`. This allows you to update the `SkeletonMecanim` skeleton in the same frame that the Mecanim Animator updated its state, which happens between `Update` and `LateUpdate`.
  - URP Shaders: Added URP "Blend Mode" shader variants for both URP 3D and URP 2D renderers. They are listed under shader name "Universal Render Pipeline/Spine/Blend Modes/" and "Universal Render Pipeline/2D/Spine/Blend Modes/" respectively.
  - URP Shaders: Added support for [Tint Black](http://en.esotericsoftware.com/spine-slots#Tint-black) functionality at "Blend Modes" Spine URP shaders (2D and 3D shaders).
  - PhysicsConstraints: Skeleton GameObjects now automatically apply Transform translation and rotation to the skeleton's `PhysicsConstraints`. You can disable applying translation or rotation at the Skeleton component Inspector under `Advanced - Physics Inheritance` by setting `Position` to (0,0)and `Rotation` to 0, or by setting the properties `physicsPositionInheritanceFactor` to `Vector2.zero` and `physicsRotationInheritanceFactor` to `0` at the skeleton component via code.
  - Added `Physics Constraints` example scene (located in `Spine Examples/Other Examples`) together with `celestial-circus` example skeleton assets. This scene demonstrates Transform movement automatically affecting physics constraints of a skeleton.
  - PhysicsConstraints: Skeleton components now allow you to use relative instead of world-space Transform movement by assigning a Transform (typically the parent) to the new `Movement relative to` property. Leave this property at `null` (the default) to use world-space Transform movement for physics.
  - PhysicsConstraints: Added Spine Preferences settings `Editor Instantiation` - `Physics Inheritance` - `Default Position` and `Default Rotation` to initialize skeletons physics settings with the desired Transform position and rotation inheritance factors when added to a scene via drag-and-drop.
  - SkeletonGraphic: Added Tint Black blend mode shaders `Spine/SkeletonGraphic Tint Black Additive`, `Spine/SkeletonGraphic Tint Black Multiply` and `Spine/SkeletonGraphic Tint Black Screen`.
  - SkeletonGraphic: Added pre-defined SkeletonGraphic material sets for main workflow parameters in folders `spine-unity/Materials` instead of requiring manual copies:
    `SkeletonGraphic-PMATexture` containing materials for premultiplied-alpha texture workflow (`Straight Alpha Texture` disabled) and `SkeletonGraphic-StaightAlphaTexture` containing materials for straight alpha texture workflow (`Straight Alpha Texture` enabled). These directories contain a set of materials with `CanvasGroup Compatible` disabled for usage with `Advanced - PMA Vertex Color` enabled at the component. Each directory also provides a subdirectory `CanvasGroupCompatible` with materials with `CanvasGroup Compatible` enabled for usage with `CanvasGroup` alpha (requiring `Advanced - PMA Vertex Color` disabled at the component).
  - SkeletonGraphic: Added auto-detect functionality for parameters `Advanced` - `Tint Black`, `CanvasGroup Compatible` and `PMA Vertex Color`. If unsure which settings are correct, hit the `Detect` button next to each parameter, in top to bottom order, or the `Detect Settings` to detect all three. Also added automatic material assignment via a `Detect Material` button in the `Advanced` section and a `Detect` button next to the `Material` property at the top of the component Inspector, as well as next to the `Blend Mode Materials` section when using multiple canvas renderers with blend modes. The suitable material is selected based on these three settings, combined with texture settings (PMA or straight alpha texture settings). If you receive incorrect results, likely your texture settings are incorrectly setup for your PMA or Straight alpha texture export settings.
  - `SkeletonRenderTexture` example components now provide a `shaderPasses` parameter to customize which passes are rendered to the `RenderTexture`. It defaults to `-1` for all passes to keep the existing behaviour. You might want to set it to `0` to only render the first pass e.g. to avoid issues when using a URP shader at the original skeleton.
  - `SkeletonGraphicRenderTexture` example component now also received a `quadMaterial` property, defaulting to the newly added Material asset `RenderQuadGraphicMaterial` which applies proper premultiplied-alpha blending of the render texture. The `quadMaterial` member variable was moved from `SkeletonRenderTexture` to the common base class `SkeletonRenderTextureBase`.
  - All Spine Outline shaders, including the URP outline shader, now provide an additional parameter `Width in Screen Space`. Enable it to keep the outline width constant in screen space instead of texture space. Requires more expensive computations, so enable only where necessary. Defaults to `disabled` to maintain existing behaviour.
  - Added support for BlendModeMaterials at runtime instantiation from files via an additional method `SkeletonDataAsset.SetupRuntimeBlendModeMaterials`. See example scene `Spine Examples/Other Examples/Instantiate from Script` for a usage example.
  - SkeletonGraphic: You can now offset the skeleton mesh relative to the pivot via a newly added green circle handle. This allows you to e.g. frame only the face of a skeleton inside a masked frame. Previously offsetting the pivot downwards fails when `Layout Scale Mode` scales the mesh smaller and towards the pivot (e.g. the feet) and thus out of the frame. Now you can keep the pivot in the center of the `RectTransform` while offsetting only the mesh downwards, keeping the desired skeleton area (e.g. the face) centered while resizing. Moving the new larger green circle handle moves the mesh offset, while moving the blue pivot circle handle moves the pivot as usual.
  - `Universal Render Pipeline/Spine/Skeleton` shader now performs proper alpha-testing when `Depth Write` is enabled, using the existing `Shadow alpha cutoff` parameter.
  - `SkeletonRootMotion` components now provide a public `Initialize()` method which is automatically called when calling `skeletonAnimation.Initialize(true)` to update the necessary skeleton references. If a different root bone shall be used, be sure to set `skeletonRootMotion.rootMotionBoneName` before calling `skeletonAnimation.Initialize(true)`.
  - Skeleton Mecanim: Added new `Mix Mode` `Match`. When selected, Spine animation weights are calculated to best match the provided Mecanim clip weights. This mix mode is recommended on any layer using blend tree nodes.
  - URP Shaders: Added `ZWrite` variant of outline shader `Universal Render Pipeline/Spine/Outline/Skeleton-OutlineOnly ZWrite`. Suitable for e.g. depth of field (DoF) effect where writing to the depth buffer is required. Note that for DoF effect, `Render Queue` needs to be set to `Alpha Test`.
  - SkeletonGraphic: Exposed `SetScaledPivotOffset` as public method outside of the editor to support programatically moving mesh offsets at runtime based on mesh bounds.
  - SkeletonMecanim: Added `Scene Preview` option to preview an Animation Clip for e.g. easier event placement. When enabled, the Animation Clip selected in the Animation window is previewed in the Scene and Game views. Lock the `SkeletonMecanim` Inspector window, open the Animation window and select the Animation Clip. Then in the Animation window scrub through the timeline to see the current animation frame previewed.
  - `Universal Render Pipeline/Spine/Skeleton Lit` shader now supports [Adaptive Probe Volumes (APV)](https://docs.unity3d.com/6000.0/Documentation/Manual/urp/probevolumes-concept.html) introduced in Unity 6. The shader also provides a new material property `APV per Pixel` to either calculate APV lighting contribution per pixel (the default) or per vertex.
  - `Universal Render Pipeline/Spine/Sprite` shader now also supports [Adaptive Probe Volumes (APV)](https://docs.unity3d.com/6000.0/Documentation/Manual/urp/probevolumes-concept.html) introduced in Unity 6. APV lighting contribution is automatically calculated per pixel.
  - All Spine Outline shaders, including the URP outline shaders, now provide an additional parameter `Fill`. Enable it to also fill the opaque area inside the outline with the outline color. Prevents a semi-transparent gap between outline and skeleton. Defaults to `disabled` to maintain existing behaviour.
  - Added example component `RenderExistingMeshGraphic` (similar to `RenderExistingMesh`) to render a `SkeletonGraphic` mesh again with different materials. This might be required by e.g. URP and SkeletonGraphic outline shaders skipping additional render passes. To add a second outline variant of your SkeletonGraphic:
    1. Add a GameObject at the same hierarchy level as the reference SkeletonGraphic and move it before the reference SkeletonGraphic to render behind.
    2. Add a `RenderExistingMeshGraphic` component.
    3. In the `RenderExistingMeshGraphic` component Inspector at `Reference Skeleton Graphic` assign the original `SkeletonGraphic` object.
    4. At `Replacement Material` assign e.g. the included _SkeletonGraphicDefaultOutline_ material to replace all materials with this material. Alternatively, if `Multiple CanvasRenderers` is enabled at the reference SkeletonGraphic, you can add entries to the `Replacement Materials` list and at each entry assign the original SkeletonGraphic material (e.g. _SkeletonGraphicDefault_) to be replaced and the respective `Replacement Material` (e.g. _SkeletonGraphicDefaultOutline_).
  - Added option for unsafe direct data loading when loading skeleton binary data to avoid some allocations, enabled via build define `SPINE_ALLOW_UNSAFE`. This define can be set via Spine Preferences, setting `Unsafe Build Defines - Direct data access`. The define is disabled by default to maintain existing behaviour. Changed asmdef setting for spine-unity assembly to allow unsafe code, has no effect other than allowing setting the `SPINE_ALLOW_UNSAFE` define.
  - Added option to `BoneFollower` components to follow attachment Z spacing offset. The Inspector component property can be found under `Follow Z Position` - `Attachment Z Spacing`. Defaults to `false` to maintain existing behaviour.

- **Breaking changes**

  - Changed `SpineShaderWithOutlineGUI` outline related methods from `private` to `protected virtual` to allow for custom shader GUI subclasses to switch to different outline shaders.
  - Changed `BoneFollower` and `BoneFollowerGraphic` methods `LateUpdate` and `Initialize` to `virtual` to allow easier overriding for e.g. positional offset in custom subclasses.
  - `MeshGenerator` received a new optimization option to avoid rendering fully transparent attachments at slot alpha 0 by default. Comment out `#define SLOT_ALPHA_DISABLES_ATTACHMENT` in `MeshGenerator.cs` to revert to previous behaviour. You may only need this option disabled when utilizing a custom shader which uses vertex color alpha for purposes other than transparency.
  - PhysicsConstraints: bool properties `ApplyTranslationToPhysics` and `ApplyRotationToPhysics` were changed to `Vector2 PhysicsPositionInheritanceFactor` and `float PhysicsRotationInheritanceFactor` to allow the Transform movement the be scaled by a factor before being applied to the skeleton. You can set the properties to `Vector2.zero` and `0` respectively to disable applying any Transform movement at all. The `Advanced` Inspector section `Physics Constraints` was renamed to `Physics Inheritance`, the properties in the section are now called `Position` and `Rotation`.
  - SkeletonGraphic Materials: Since the addition of new material sets for the `CanvasGroupCompatible` parameters, the default SkeletonGraphic materials all have `CanvasGroup Compatible` disabled. Please assign the respective material from the `CanvasGroupCompatible` material subdirectory if you want `CanvasGroup Compatible` enabled at your SkeletonGraphic.
  - SkeletonGraphic: The parameter `SkeletonGraphic.MeshGenerator.settings.canvasGroupTintBlack` was changed to `canvasGroupCompatible` to help with auto-detecting correct Vertex Data and Material settings. Set the parameter to true if the SkeletonGraphic component is located below a `CanvasGroup` component. The parameter value is automatically migrated from `canvasGroupTintBlack`.
  - Inspector: String attribute `SpineSkin()` now allows to include `<None>` in the list of parameters. Previously the `includeNone=true` parameter of the `SpineSkin()` attribute defaulted to `true` but was ignored. Now it defaults to `false` and has an effect on the list. Only the Inspector GUI is affected by this behaviour change.
  - `SkeletonGraphicRenderTexture` example component: `protected RawImage quadRawImage` was changed to `protected SkeletonSubmeshGraphic quadMaskableGraphic` for a bugfix. This is only relevant for subclasses of `SkeletonGraphicRenderTexture` or when querying the `RawImage` component via e.g. `skeletonGraphicRenderTexture.quad.GetComponent<RawImage>()`.
  - Fixed a bug where when Linear color space is used and `PMA vertex colors` enabled, additive slots add a too dark (too transparent) color value. If you want the old incorrect behaviour (darker additive slots) or are not using Linear but Gamma color space, you can comment-out the define `LINEAR_COLOR_SPACE_FIX_ADDITIVE_ALPHA` in `MeshGenerator.cs` to deactivate the fix or just to skip unnecessary instructions.
  - Fixed SkeletonRootMotion components ignoring parent bone scale when set by transform constraints. Using applied scale of parent bone now. If you need the old behaviour, comment out the line `#define USE_APPLIED_PARENT_SCALE` in SkeletonRootMotionBase.cs.
  - Fixed SkeletonUtility callback update order when used with SkeletonRootMotion components so that the position when following a bone is updated after SkeletonRootMotion clears root-bone position. The order of SkeletonUtilityBone callbacks is changed to be later to achieve this. This is a breaking change in the unlikely case that you are using SkeletonRootMotion together with SkeletonUtility and subscribed to `UpdateLocal`, `UpdateWorld` or `UpdateComplete` yourself and relied on a certain callback order. One solution is to then resubscribe your own callback events accordingly by calling
  `.UpdateLocal -= Callback; .UpdateLocal += Callback;`.

- **Changes of default values**

- **Deprecated**

- **Restructuring (Non-Breaking)**

### XNA/MonoGame

- **Additions**
  - Apply external movement to physics: If you are not directly modifying `Skeleton.X` or `Skeleton.Y`, you can apply external game object movement to skeleton physics as follows:
    Add a `Vector2 lastPosition;` member variable to your class interacting with the skeleton. Then call e.g. the following code each frame:
    ```
    Vector2 currentPosition = <current world position>;
    Vector2 externalPositionDelta = currentPosition - lastPosition;
    skeleton.PhysicsTranslate(externalPositionDelta.x, externalPositionDelta.y);
    lastPosition = currentPosition;
    ```

## Java

- Added physics support
  - Added `PhysicsConstraintXXXTimeline` and `PhysicsConstraintResetTimeline`
  - Added `Physics` to be passed to `Skeleton#updateWorldTransform()`
  - Added `SkeletonData#findPhysicsConstraint()` and `SkeletonData#getPhysicsConstraints()` to query physics constraints
  - Added `Skeleton#findPhysicsConstraint()` and `Skeleton#getPhysicsConstraints()` to query physics constraints
  - Added `Skeleton#physicsTranslate()` to translate all physics constraints by some distances in the skeleton coordinate system
  - Added `Skeleton#physicsRotate()` to rotate all physics constraints by some distances in the skeleton coordinate system
  - Added `Skeleton#time` and respective setters/getters to keep track of time for physics simulations
  - See also breaking changes for `Skeleton#updateWorldTransform()` and the requirement to call `Skeleton#update()` to advance
    pyhsics each frame.
- Added `InheritTimeline`
- Added [`TrackEntry#alphaAttachmentThreshold`](http://esotericsoftware.com/spine-api-reference#TrackEntry-alphaAttachmentThreshold)
- Added `TrackEntry#setMixDuration()` to set the mix duration in conjunction with a delay
- Added `TrackEntry#wasApplied()` to check if the entry has been applied
- Added `Bone#worldToParent()` to transform coordinates from world space to the parent space of a bone
- Added `Bone#localToParent()` to transform coordinates from a bone's local space to its parent space
- Added non essential fields `icon` and `visible` to `BoneData`
- Added non essential fields `path` and `visible` to `SlotData`
- Added `setToSetupPose()` to all contraint classes
- **Breaking changes**
  - Renamed `TrackEntry#attachmentThreshold` to `TrackEntry#mixAttachmentThreshold` along with respective getters/settesr
  - Renamed `TrackEntry::drawOrderThreshold` to `TrackEntry#mixDrawOrdertThreshold` along with respective getters/settesr
  - Renamed `TransformMode` to `Inherit` and all `TransformMode_*` enums to `Inherit_*`
  - You must call `Skeleton#update(delta)` before calling `Skeleton#updateWorldTransform()` if the frame time has advanced. This is needed to update physics accordingly
  - `Skeleton#updateWorldTransform()` takes an additional `Physics` parameter. See the `Physics` documentation for information on what the different enum values do
  - All `Updatable` sub-classes like `Bone` and constraints now take an additional `Physics` parameter for their `update()` methods

### libGDX

- Added physics examples

## Typescript/Javascript

- Added physics support
  - Added `PhysicsConstraintXXXTimeline` and `PhysicsConstraintResetTimeline`
  - Added `Physics` to be passed to `Skeleton#updateWorldTransform()`
  - Added `SkeletonData#findPhysicsConstraint()` and `SkeletonData#getPhysicsConstraints()` to query physics constraints
  - Added `Skeleton#findPhysicsConstraint()` and `Skeleton#getPhysicsConstraints()` to query physics constraints
  - Added `Skeleton#physicsTranslate()` to translate all physics constraints by some distances in the skeleton coordinate system
  - Added `Skeleton#physicsRotate()` to rotate all physics constraints by some distances in the skeleton coordinate system
  - Added `Skeleton#time` and respective setters/getters to keep track of time for physics simulations
  - See also breaking changes for `Skeleton#updateWorldTransform()` and the requirement to call `Skeleton#update()` to advance
    pyhsics each frame.
- Added `InheritTimeline`
- Added [`TrackEntry#alphaAttachmentThreshold`](http://esotericsoftware.com/spine-api-reference#TrackEntry-alphaAttachmentThreshold)
- Added `TrackEntry#setMixDuration()` to set the mix duration in conjunction with a delay
- Added `TrackEntry#wasApplied()` to check if the entry has been applied
- Added `Bone#worldToParent()` to transform coordinates from world space to the parent space of a bone
- Added `Bone#localToParent()` to transform coordinates from a bone's local space to its parent space
- Added non essential fields `icon` and `visible` to `BoneData`
- Added non essential fields `path` and `visible` to `SlotData`
- Added `setToSetupPose()` to all contraint classes
- **Breaking changes**
  - Renamed `TrackEntry#attachmentThreshold` to `TrackEntry#mixAttachmentThreshold` along with respective getters/settesr
  - Renamed `TrackEntry::drawOrderThreshold` to `TrackEntry#mixDrawOrdertThreshold` along with respective getters/settesr
  - Renamed `TransformMode` to `Inherit` and all `TransformMode_*` enums to `Inherit_*`
  - You must call `Skeleton#update(delta)` before calling `Skeleton#updateWorldTransform()` if the frame time has advanced. This is needed to update physics accordingly
  - `Skeleton#updateWorldTransform()` takes an additional `Physics` parameter. See the `Physics` documentation for information on what the different enum values do
  - All `Updatable` sub-classes like `Bone` and constraints now take an additional `Physics` parameter for their `update()` methods

### WebGL backend

- Added physics examples

### Canvas backend

### CanvasKit backend

- Added spine-canvaskit runtime. See https://esotericsoftware.com/spine-canvaskit

### Three.js backend

- Added physics support

### Player

- Added physics support
- Added `scale` field to configuration which defines the scale to load the skeleton at
- Added `updateWorldTransform` field to configuration which expects a function that updates the skeleton. Defaults to player.skeleton.updateWorldTransform(spine.Physics.update)
- Added `skeleton` to `SpinePlayerConfig` to specify the URL of the skeleton .json or .skel file. Deprecated `jsonURL` and `binaryURL`. The old fields can still be used, but will be removed in Spine 4.3
- Added `atlas` to `SpinePlayerConfig` to specify the URL of the .atlas file. Deprecated `atlasURL`. The old field can still be used, but will be removed in Spine 4.3.

### Pixi

- Added spine-pixi runtime, also backported to Spine 4.1. See https://esotericsoftware.com/spine-pixi

### Phaser

- Added spine-phaser runtime, also backported to Spine 4.1. See https://esotericsoftware.com/spine-phaser

## Haxe

- Added spine-haxe runtime, also backported to Spine 4.1. See https://esotericsoftware.com/spine-haxe

## Flutter

- Added spine-flutter runtime, also backported to Spine 4.1. See https://esotericsoftware.com/spine-flutter

# 4.1

## C

- **Additions**
  - Support for sequences.
  - Support for `shortestRotation` in animation state. See https://github.com/esotericsoftware/spine-runtimes/issues/2027.
  - Added CMake parameter `SPINE_SANITIZE` which will enable sanitizers on macOS and Linux.
  - Added `SPINE_MAJOR_VERSION`, `SPINE_MINOR_VERSION`, and `SPINE_VERSION_STRING`. Parsing skeleton .JSON and .skel files will report an error if the skeleton version does not match the runtime version.
- **Breaking changes**
  - `spRegionAttachment` and `spMeshAttachment` now contain a `spTextureRegion*` instead of encoding region fields directly.
  - `sp_AttachmentLoader_newRegionAttachment()` and `spAttachmentLoader_newMeshAttachment()` now take an additional `Sequence*` parameter.
  - `spMeshAttachment_updateUVs()` was renamed to `spMeshAttachment_updateRegion()`.
  - `spRegionAttachment_updateOffset()` was renamed to `spRegionAttachment_updateRegion()`, `spRegionAttachment_setUVs()` was merged into `spRegionAttachment_updateRegion()`.
  - `spSlot_getAttachmentTime()` and `spSlot_setAttachmentTime()` have been removed.
  - `spVertexAttachment->deformAttachment` was renamed to `spVertexAttachment->timelineAttachment`.
  - `spSkeleton_update()` has been removed.
  - `spSkeleton->time` has been removed.
  - `spVertexEffect` has been removed.

### SFML

- Updated example to use SFML 2.5.1.
- Added dragon example.

## C++

- **Additions**
  - Support for sequences.
  - Support for `shortestRotation` in animation state. See https://github.com/esotericsoftware/spine-runtimes/issues/2027.
  - Added CMake parameter `SPINE_SANITIZE` which will enable sanitizers on macOS and Linux.
    - Added `SPINE_MAJOR_VERSION`, `SPINE_MINOR_VERSION`, and `SPINE_VERSION_STRING`. Parsing skeleton .JSON and .skel files will report an error if the skeleton version does not match the runtime version.
  - Added `SkeletonBounds::getBoundingBox()`, `SkeletonBounds::getPolygons()`, and `SkeletonBounds::getBoundingBoxes()`.
- **Breaking changes**
  - `RegionAttachment` and `MeshAttachment` no longer implement `HasRendererObject`.
  - `RegionAttachment` and `MeshAttachment` now contain a `TextureRegion*` instead of encoding region fields directly.
  - `AttachmentLoader::newRegionAttachment()` and `AttachmentLoader::newMeshAttachment()` now take an additional `Sequence*` parameter.
  - `MeshAttachment::updateUVs()` was renamed to `MeshAttachment::updateRegion()`.
  - `RegionAttachment::updateOffset()` was renamed to `RegionAttachment::updateRegion()`, `RegionAttachment::setUVs()` was merged into `updateRegion()`.
  - `Slot::getAttachmentTime()` and `Slot::setAttachmentTime()` have been removed.
  - `VertexAttachment::getDeformAttachment()` was renamed to `VertexAttachment::getTimelineAttachment()`.
  - `Skeleton::update()` has been removed.
  - `Skeleton::getTime()` has been removed.
  - `VertexEffect` has been removed.

### Cocos2d-x
- Renamed `SkeletonRenderer` to `SkeletonRendererCocos2dX` to avoid name clash with spine-cpp class.

### SFML

- Updated example to use SFML 2.5.1.
- Added dragon example.

### UE4

- Updated example project to UE 4.27

## C#

- **Additions**

  - Full support for sequences.
  - Support for `shortestRotation` in animation state. See https://github.com/esotericsoftware/spine-runtimes/issues/2027.
  - `RegionAttachment` and `MeshAttachment` now provide a `Region` property. Use this property instead of the removed `RendererObject` property (see section _Breaking Changes_ below).

- **Breaking changes**
  - Removed `RendererObject` property from `RegionAttachment` and `MeshAttachment`. Use `attachment.Region` property instead. Removed removed `IHasRendererObject` interface. Use `IHasTextureRegion` instead.
  - Replaced `RegionAttachment.UpdateOffset` and `MeshAttachment.UpdateUVs` with `Attachment.UpdateRegion`. The caller must ensure that the attachment's region is not `null`.
  - Removed `AttachmentRegionExtensions` methods `Attachment.SetRegion`, `MeshAttachment.SetRegion` and `RegionAttachment.SetRegion(region, update)`. Use `attachment.Region = region; if (update) attachment.UpdateRegion()` instead.
  - `AttachmentLoader.NewRegionAttachment()` and `AttachmentLoader.NewMeshAttachment()` take an additional `Sequence` parameter.
  - `VertexAttachment.DeformAttachment` property has been replaced with `VertexAttachment.TimelineAttachment`.
  - `RegionAttachment.ComputeWorldVertices()` takes a `Slot` instead of a `Bone` as the first argument.
  - Removed `Skeleton.Update(float deltaTime)` method.
  - Removed `Slot.AttachmentTime` property.
  - Removed extension method `AtlasRegion.GetSpineAtlasRect()` parameter `includeRotate` (with default value `true`). Most likely this method was never used with `includeRotate=false` in user code so no changes are required.
  - `AtlasRegion.PackedWidth` and `AtlasRegion.PackedHeight` are swapped compared to 4.0 when packing rotation is equal to 90 degrees. Most likely this property was never accessed in user code so no changes are required.

### Unity

- **Officially supported Unity versions are 2017.1-2023.1**.

- **Additions**

  - `SpineAtlasAsset.CreateRuntimeInstance` methods now provide an optional `newCustomTextureLoader` parameter (defaults to `null`) which can be set to e.g. `(a) => new YourCustomTextureLoader(a)` to use your own `TextureLoader` subclass instead of `MaterialsTextureLoader`.
  - `SkeletonAnimation`, `SkeletonMecanim` and `SkeletonGraphic` now provide an Inspector parameter `Advanced` - `Animation Update` with modes `In Update` **(previous behaviour, the default)**, `In FixedUpdate` and `Manual Update`. This allows to update animation in `FixedUpdate` when using the `SkeletonRootMotion` component (which is the recommended combination now, issuing a warning otherwise). The reason is that when root motion leads to a collision with a physics collider, it can introduce jittery excess movement when updating animation in `Update` due to more `Update` calls following a single `FixedUpdate` call.
  - Added `SkeletonRootMotion` properties `PreviousRigidbodyRootMotion` and `AdditionalRigidbody2DMovement`. Setting or querying these movement vectors can be necessary when multiple scripts call `Rigidbody2D.MovePosition` on the same object where the last call overwrites the effect of preceding ones.
  - `BoneFollower` and `BoneFollowerGraphic` now provide an additional `Follow Parent World Scale` parameter to allow following simple scale of parent bones (rotated/skewed scale can't be supported).
  - Improved `Advanced - Fix Prefab Override MeshFilter` property for `SkeletonRenderer` (and subclasses`SkeletonAnimation` and `SkeletonMecanim`), now providing an additional option to use a global value which can be set in `Edit - Preferences - Spine`.
  - Timeline naming improvements: `Spine AnimationState Clip` Inspector parameter `Custom Duration` changed and inverted to `Default Mix Duration` for more clarity. Shortened all Timeline add track menu entries from: `Spine.Unity.Playables - <track type>` to `Spine - <track type>`, `Spine Animation State Track` to `SkeletonAnimation Track`, `Spine AnimationState Graphic Track` to `SkeletonGraphic Track`, and `Spine Skeleton Flip Track` to `Skeleton Flip Track`.
  - Timeline track appearance and Inspector: Tracks now show icons and track colors to make them easier to distinguish. When a Track is selected, the Inspector now shows an editable track name which was previously only editable at the Timeline asset.
  - Added example component `SkeletonRenderTexture` to render a `SkeletonRenderer` to a `RenderTexture`, mainly for proper transparency. Added an example scene named `RenderTexture FadeOut Transparency` that demonstrates usage for a fadeout transparency effect.
  - Added another fadeout example component named `SkeletonRenderTextureFadeout` which takes over transparency fadeout when enabled. You can use this component as-is, attach it in disabled state and enable it to start a fadeout effect.
  - Timeline clips now offer an additional `Alpha` parameter for setting a custom constant mix alpha value other than 1.0, just as `TrackEntry.Alpha`. Defaults to 1.0.
  - `GetRemappedClone` copying from `Sprite` now provides additional `pmaCloneTextureFormat` and `pmaCloneMipmaps` parameters to explicitly specify the texture format of a newly created PMA texture.
  - Spine property Inspector fields (`Animation Name`, `Bone Name`, `Slot` and similar) now display the name in red when the respective animation/bone/etc no longer exists at the skeleton data. This may be helpful when such items have been renamed or deleted.
  - Added `UnscaledTime` property at `SkeletonAnimation` as well, behaving like `SkeletonGraphic.UnscaledTime`. If enabled, AnimationState uses unscaled game time (`Time.unscaledDeltaTime`), running animations independent of e.g. game pause (`Time.timeScale`).
  - `SkeletonAnimation`, `SkeletonMecanim` and `SkeletonGraphic` now provide an additional `OnAnimationRebuild` callback delegate which is issued after both the skeleton and the animation state have been initialized.
  - Timeline `SkeletonAnimation Track` and `SkeletonGraphic Track` now provide an `Unscaled Time` property. Whenever starting a new animation clip of this track, `SkeletonAnimation.UnscaledTime` or `SkeletonGraphic.UnscaledTime` will be set to this value. This allows you to play back Timeline clips either in normal game time or unscaled game time. Note that `PlayableDirector.UpdateMethod` is ignored and replaced by this property, which allows more fine-granular control per Timeline track.
  - Added `SkeletonRootMotion` callback delegates `ProcessRootMotionOverride` and `PhysicsUpdateRootMotionOverride` to customize how root motion is applied. The new property `disableOnOverride` determines whether the callback will be issued in addition or instead of normally applying root motion. Added property `rootMotionScaleRotation` to allow scaling rotational root-motion to match e.g. a 90 degree rotation to a custom target angle.
  - Added outline shader parameter `Advanced - Opaque Alpha` which can be used to exclude problematic semi-transparent areas, which may receive an undesired large outline color overlay otherwise.
  - Added Spine Preferences setting `Prefabs` - `Optimize Preview Meshes`. When enabled, Spine prefab preview meshes will be removed in a pre-build step to reduce build size. This increases build time as all prefabs in the project will be processed. Defaults to false to not slow down builds substantially every time.
  - Added Spine Preferences setting `Reload SkeletonData after Play`. When enabled, the shared `SkeletonData` of all skeletons in the active scene is reloaded (from the `.json` or `.skel.bytes` file) after exiting play-mode. You can disable this setting to avoid the reloading delay if you can ensure that there are no (accidental) modifications to the shared `SkeletonData` during play-mode (otherwise it would carry over its effect into subsequent plays). Defaults to `true` (the safe setting), which maintains existing behaviour.
  - Added `SkeletonAnimationMulti` sample component methods `SetActiveSkeleton(int index)` and getter property `SkeletonAnimations` to more easily apply changes at all SkeletonAnimation instances instead of only the active one.
  - PMA textures now have `sRGB (Color Texture)` disabled by default, the preset template `PMATexturePreset.preset` has been adjusted accordingly. As PMA textures are only allowed with Gamma color space, `sRGB (Color Texture)` shall be disabled to prevent border artifacts when mipmaps are enabled. In Gamma color space having this setting disabled has no drawbacks, only benefits.
  - `SkeletonRenderTexture` and `SkeletonGraphicRenderTexture` components now support automatic down-scaling when required size on screen exceeds `Max Render Texture Size`.
  - Added `Spine/SkeletonGraphic Fill` shader to provide functionality of `Spine/Skeleton Fill` shader for `SkeletonGraphic`.
  - Lit Spine URP shaders (`Universal Render Pipeline/Spine/Sprite` and `Universal Render Pipeline/Spine/Skeleton Lit`) now support `Forward+` rendering path as introduced by Unity 2022.2 and URP version 14.
  - `SkeletonGraphic` now supports automatic scaling based on its `RectTransform` bounds. Automatic scaling can be enabled by setting the added `Layout Scale Mode` Inspector property to either `Width Controls Height`, `Height Controls Width`, `FitInParent` or `EnvelopeParent`. It is set to `None` by default to keep previous behaviour and avoid breaking existing projects. To modify the reference layout bounds, hit the additional `Edit Layout Bounds` toggle button to switch into edit mode, adjust the bounds or hit `Match RectTransform with Mesh`, and hit the button again when done adjusting. The skeleton will now be scaled accordingly to fit the reference layout bounds to the object's `RectTransform`.
  - Added previously missing unlit URP 2D shader variant, available under `Universal Render Pipeline/2D/Spine/Skeleton`.
  - Added support for light cookies at `Universal Render Pipeline/Spine/Sprite` shader.
  - Timeline extension package: An additional Spine preferences parameter `Timeline` - `Default Mix Duration` has been added, setting newly added `SpineAnimationStateClip` clips accordingly, defaults to false. This Spine preferences parameter can be enabled to default to the previous behaviour before this update.
  - Tint Black: Added support for [Tint Black](http://en.esotericsoftware.com/spine-slots#Tint-black) functionality at all Spine URP shaders (2D and 3D shaders) and at all standard pipeline `Spine/Sprite` shaders. This feature can be enabled via the `Tint Black` material parameter in the Inspector. Note: The URP Sprite shaders provided in the Spine URP Shaders extension UPM package require the latest version of the spine-unity runtime (package version 4.1.12, 2023-05-31 or newer) to display the added material parameters in the Inspector GUI.
  - Added `SkeletonGraphic.MeshScale` property to allow access to calculated mesh scale. `MeshScale` is based on (1) Canvas pixels per unit, and (2) `RectTransform` bounds when using `Layout Scale Mode` other than `None` at `SkeletonGraphic` which scales the skeleton mesh to fit the parent `RectTransform` bounds accordingly.
  - Added `updateSeparatorPartScale` property to `SkeletonGraphic` to let render separator parts follow the scale (lossy scale) of the `SkeletonGraphic` GameObject. Defaults to `false` to maintain existing behaviour.
  - Added experimental `EditorSkeletonPlayer` component to allow Editor playback of the initial animation set at `SkeletonAnimation` or `SkeletonGraphic` components. Add this component to your skeleton GameObject to enable the in-editor animation preview. Allows configurations for continuous playback when selected, deselected, and alternative single-frame preview by setting `Fixed Track Time` to any value other than 0. Limitations: At skeletons with variable material count the Inspector preview may be too unresponsive. It is then recommended to disable the `EditorSkeletonPlayer` component (at the top of the Inspector) to make it responsive again, then you can disable `Play When Selected` and re-enable the component to preview playback only when deselected.
  - Added example component `RenderCombinedMesh` to render a combined mesh of multiple meshes or submeshes. This is required by `OutlineOnly` shaders to render a combined outline when using `SkeletonRenderSeparator` or multiple atlas pages which would normally lead to outlines around individual parts. To add a combined outline to your SkeletenRenderer:
    1. Add a child GameObject and move it a bit back (e.g. position Z = 0.01).
    2. Add a `RenderCombinedMesh` component, provided in the `Spine Examples/Scripts/Sample Components` directory.
    3. Copy the original material, add _\_Outline_ to its name and set the shader to your outline-only shader like `Universal Render Pipeline/Spine/Outline/Skeleton-OutlineOnly` or `Spine/Outline/OutlineOnly-ZWrite`.
    4. Assign this _\_Outline_ material at the new child GameObject's `MeshRenderer` component.
       If you are using `SkeletonRenderSeparator` and need to enable and disable the `SkeletonRenderSeparator` component at runtime, you can increase the `RenderCombinedMesh` `Reference Renderers` array by one and assign the `SkeletonRenderer` itself at the last entry after the parts renderers. Disabled `MeshRenderer` components will be skipped when combining the final mesh, so the combined mesh is automatically filled from the desired active renderers.
  - Timeline extension package: Added static `EditorEvent` callback to allow editor scripts to react to animation events outside of play-mode. Register to the events via `Spine.Unity.Playables.SpineAnimationStateMixerBehaviour.EditorEvent += YourCallback;`.
  - URP Shaders: Added `Depth Write` property to shaders `Universal Render Pipeline/Spine/Skeleton` and `Universal Render Pipeline/Spine/Skeleton Lit`. Defaults to false to maintain existing behaviour.
  - Added `Animation Update` mode (called `UpdateTiming` in code) `In Late Update` for `SkeletonAnimation`, `SkeletonMecanim` and `SkeletonGraphic`. This allows you to update the `SkeletonMecanim` skeleton in the same frame that the Mecanim Animator updated its state, which happens between `Update` and `LateUpdate`.
  - URP Shaders: Added URP "Blend Mode" shader variants for both URP 3D and URP 2D renderers. They are listed under shader name "Universal Render Pipeline/Spine/Blend Modes/" and "Universal Render Pipeline/2D/Spine/Blend Modes/" respectively.
  - URP Shaders: Added support for [Tint Black](http://en.esotericsoftware.com/spine-slots#Tint-black) functionality at "Blend Modes" Spine URP shaders (2D and 3D shaders).

- **Breaking changes**

  - Made `SkeletonGraphic.unscaledTime` parameter protected, use the new property `UnscaledTime` instead.
  - `SkeletonGraphic` `OnRebuild` callback delegate is now issued after the skeleton has been initialized, before the `AnimationState` component is initialized. This makes behaviour consistent with `SkeletonAnimation` and `SkeletonMecanim` component behaviour. Use the new callback `OnAnimationRebuild` if you want to receive a callback after the `SkeletonGraphic` `AnimationState` has been initialized.
  - Changed name of prefab skeleton meshes stored at prefabs from `Skeleton Prefab Mesh "name"` to `Skeleton Prefab Mesh [name]` to avoid issues with quotes in mesh asset names (see [this issue](https://github.com/EsotericSoftware/spine-runtimes/issues/2572)). Likely this change poses no problems at all, however if you are parsing the prefab's mesh name for whatever reason, be sure to adjust the pattern accordingly.

- **Changes of default values**

- **Deprecated**

  - Shader macro `RETURN_UNLIT_IF_ADDITIVE_SLOT` in `spine-unity/Shaders/Sprite/CGIncludes/ShaderShared.cginc` has been deprecated and will be removed in spine-unity 4.2. Use RETURN_UNLIT_IF_ADDITIVE_SLOT_TINT instead.

- **Restructuring (Non-Breaking)**
  - Moved Spine URP Shaders Examples directory from the main package directory to Samples which can be installed via the Unity Package Manager. To import, select the `Spine Universal RP Shaders` package in the Package Manager window, expand `Samples` at the bottom and hit `Import` next to `Examples`. This follows the standard [samples guideline](https://docs.unity3d.com/Manual/cus-samples.html) and prevents warning messages about unexpectedly altered immutable assets.

### XNA/MonoGame

- **Breaking change**: Removed spine-xna in favor of spine-monogame. See https://github.com/EsotericSoftware/spine-runtimes/issues/1949
- Added new spine-monogame solution. See [spine-monogame/README.md](spine-monogame/README.md) for updated instructions on how to use spine-monogame.

## Java

- **Additions**
  - Support for `shortestRotation` in animation state. See https://github.com/esotericsoftware/spine-runtimes/issues/2027.
  - Support for sequences.
- **Breaking changes**
  - `AttachmentLoader#newRegionAttachment()` and `AttachmentLoader#newMeshAttachment()` take an additional `Sequence` parameter.
  - `Slot#setAttachmentTime()` and `Slot#getAttachmentTime()` have been removed.
  - `VertexAttachment#setDeformAttachment()` and `VertexAttachment#getDeformAttachment()` have been replaced with `VertexAttachment#setTimelineAttachment()` and `VertexAttachment#getTimelineAttachment()`.
  - `RegionAttachment#updateOffset()` has been renamed to `RegionAttachment#updateRegion()`. The caller must ensure that the attachment's region is not `null`.
  - `RegionAttachment#computeWorldVertices()` takes a `Slot` instead of a `Bone` as the first argument.
  - `VertexEffect` has been removed.

### libGDX

- `spine-libgdx`, `spine-libgdx-tests`, and `spine-skeletonviewer` are now fully Gradle-ified.
- `spine-skeletonviewer` now supports quickly loading skeletons by dragging and dropping `.json` or `.skel` skeleton files onto the window.

## Typescript/Javascript

- **Additions**
  - full support for sequences.
  - Added `Promise` based `AssetManager.loadAll()`. Allows synchronous waiting via `await assetManager.loadAll()`, simplifying loader logic in applications.
  - Support for `shortestRotation` in animation state. See https://github.com/esotericsoftware/spine-runtimes/issues/2027.
  - Full support for sequences.
- **Breaking changes**
  - `AttachmentLoader#newRegionAttachment()` and `AttachmentLoader#newMeshAttachment()` take an additional `Sequence` parameter.
  - `Slot#attachmentTime` and has been removed.
  - `VertexAttachment#deformAttachment` has been replaced with `VertexAttachment#timelineAttachment`.
  - `RegionAttachment#updateOffset()` has been renamed to `RegionAttachment#updateRegion()`. The caller must ensure that the attachment's region is not `null`.
  - `RegionAttachment#computeWorldVertices()` takes a `Slot` instead of a `Bone` as the first argument.
  - Removed `PlayerEditor`.
  - `VertexEffect` has been removed.
  - Removed `RegionAttachment.rendererObject`.
  - Renamed `TextureRegion.renderObject` to `TextureRegion.texture`.

### WebGL backend

- `PolygonBatcher` can now disable culling automatically if the static variable `PolygonBatcher.disableCulling` is set to true.
- Added `SpineCanvas`, a simpler way to render a scene via spine-webgl. See `spine-ts/spine-webgl/examples/barebones.html` and `spine-ts/spine-webgl/examples/mix-and-match.html`.
- Added `SpineCanavs.dispose()` to halt the updating and rendering of the canvas.

### Canvas backend

- Improved example.

### Three.js backend

- Added orbital controls to THREJS example.
- `SkeletonMesh` takes an optional `SkeletonMeshMaterialCustomizer`, allowing modification of materials used by `SkeletonMesh`.
- Added `SkeletonMeshMaterial.alphaTest`, when > 0, alpha testing will be performed and fragments will not be written to the depth buffer, if depth writes are enabled.

### Player

- Added `SpinePlayer.dispose()` to explicitely dispose of all resources the player holds on to.

# 4.0

## AS3

**NOTE: Spine 4.0 will be the last release supporting spine-as3. Starting from Spine 4.1, spine-as3 will no longer be supported or maintained.**

- Switched projects from FDT to Visual Studio Code. See updated `README.md` files for instructions.
- Expose non-essential colors on bones, bounding box, clipping, and path attachments.
- Timeline API has been extended to support component-wise timelines exported by Spine 4.0.
- Added `AnimationState.clearNext()` which removes the given `TrackEntry` and all entries after it.
- Added support for texture atlas key value pairs, see `AtlasRegion.names` and `AtlasRegion.values`.
- Added support for reverse animation playback via `TrackEntry.reverse`.
- Added proportional spacing mode support for path constraints.
- Added support for uniform scaling for two bone IK.
- Fixed applying a constraint reverting changes from other constraints.

### Starling

**NOTE: Spine 4.0 will be the last release supporting spine-starling. Starting from Spine 4.1, spine-starling will no longer be supported or maintained.**

- Switched projects from FDT to Visual Studio Code. See updated `README.md` files for instructions.
- Updated to Starling 2.6 and Air SDK 33.

## C

- **Breaking change:** Removed `SPINE_SHORT_NAMES` define and C++ constructors.
- Timeline API has been extended to support component-wise timelines exported by Spine 4.0.
- Added `spAnimationState_clearNext()` which removes the given `spTrackEntry` and all entries after it.
- Added support for texture atlas key value pairs, see `spAtlasRegion.keyValues`.
- Added support for reverse animation playback via `spTrackEntry.reverse`.
- Added proportional spacing mode support for path constraints.
- Added support for uniform scaling for two bone IK.
- Fixed applying a constraint reverting changes from other constraints.

### Cocos2d-Objc

**NOTE: Spine 4.0 will be the last release supporting spine-cocos2d-objc. Starting from Spine 4.1, spine-cocos2d-objc will no longer be supported or maintained.**

### SFML

- Added `ikDemo()` in `main.cpp`. to illustrate how to drive a bone and IK chain through mouse movement.

## C++

- Removed dependency on STL throughout the code base, cutting down on the LOC that need parsing by 66%.
- Exposed `x` and `y` on `SkeletonData` through getters and setters.
- Expose non-essential colors on bones, bounding box, clipping, and path attachments.
- Timeline API has been extended to support component-wise timelines exported by Spine 4.0.
- Added `AnimationState.clearNext()` which removes the given `TrackEntry` and all entries after it.
- Added support for texture atlas key value pairs, see `AtlasRegion.names` and `AtlasRegion.values`.
- Added support for reverse animation playback via `TrackEntry.reverse`.
- Added proportional spacing mode support for path constraints.
- Added support for uniform scaling for two bone IK.
- Fixed applying a constraint reverting changes from other constraints.
- spine-cpp now requires C++11.

### Cocos2d-x

- Added `IKExample` scene to illustrate how to drive a bone and IK chain through mouse movement.
- Added `SkeletonAnimation::setPreUpdateWorldTransformsListener()` and `SkeletonAnimation::setPostUpdateWorldTransformsListener()`. This allows users to modify bone transforms and other skeleton properties before and after the world transforms of all bones are calculated. See the `IKExample` for a usage example.

### SFML

- Added `ikDemo()` in `main.cpp`. to illustrate how to drive a bone and IK chain through mouse movement.

### UE4

- `SpineWidget` now supports the full widget transform, including rendering scale/shear.
- Materials on `SkeletonRendererComponent` are now blueprint read and writeable. This allows setting dynamic material instances at runtime.
- Added `InitialSkin` property to `USpineWidget`. This allows previewing different skins in the UMG Designer. Initial skins can still be overridden via blueprint events such as `On Initialized`.
- **Breaking change:** `SpineWidget` no longer has the `Scale` property. Instead the size x/y properties can be used.
- Added `SetSlotColor` on `USpineSkeletonComponent` to easily set the color of a slot via blueprints.
- Changed mixes set on an `SkeletonDataAsset` will now be applied to instances of `USpineSkeletonComponent`.
- Generated normals are now correctly flipped for back faces.
- Modifying parent materials updates material instances accordingly.
- Only `.json` files that are actually encoding Spine skeletons will be loaded. Other `.json` files will be left to other importers.
- Updated example project to UE 4.27.

## C#

- Timeline API has been extended to support component-wise timelines exported by Spine 4.0.
- Added `AnimationState.clearNext()` which removes the given `TrackEntry` and all entries after it.
- Added support for texture atlas key value pairs, see `AtlasRegion.names` and `AtlasRegion.values`.
- Added support for reverse animation playback via `TrackEntry.Reverse`.
- Added proportional spacing mode support for path constraints.
- Added support for uniform scaling for two bone IK.
- Fixed applying a constraint reverting changes from other constraints.
- **Breaking change:** Removed `SkeletonData` and `Skeleton` methods: `FindBoneIndex`, `FindSlotIndex`. Bones and slots have an `Index` field that should be used instead. Be sure to check for e.g. `bone == null` accordingly before accessing `bone.Index`.

### Unity

- **Officially supported Unity versions are 2017.1-2022.1**.
- **Breaking changes**

  - Removed all `Spine.Unity.AttachmentTools.SkinUtilities` Skin extension methods. These have become obsoleted and error-prone since the introduction of the new Skin API in 3.8. To fix any compile errors, replace any usage of `Skin` extension methods with their counterparts, e.g. replace occurrances of `skin.AddAttachments()` with `skin.AddSkin()`. Please see the example scene `Mix and Match Skins` on how to use the new Skin API to combine skins, or the updated old example scenes `Mix and Match` and `Mix and Match Equip` on how you can update an existing project using the old workflow. If you are using `skeletonAnimation.Skeleton.UnshareSkin()` in your code, you can replace it with `Skin customSkin = new Skin("custom skin"); customSkin.AddSkin(skeletonAnimation.Skeleton.Skin);`.
  - `Skin.GetAttachments()` has been replaced by `Skin.Attachments`, returning an `ICollection<SkinEntry>`. This makes access more consistent and intuitive. To fix any compile errors, replace any occurrances of `Skin.GetAttachments()` by `Skin.Attachments`.
  - Removed redundant `Spine.Unity.AttachmentTools.AttachmentCloneExtensions` extension methods `Attachment.GetCopy()` and `Attachment.GetLinkedMesh()`. To fix any compile errors, replace any occurrances with `Attachment.Copy()` and `Attachment.NewLinkedMesh()`.
  - Removed `Spine.Unity.AttachmentTools.AttachmentRegionExtensions` extension methods `Attachment.GetRegion()`. Use `Attachment.RendererObject as AtlasRegion` instead.
  - Removed redundant `Spine.SkeletonExtensions` extension methods:
    Replace:

    - `Skeleton.SetPropertyToSetupPose()`
    - `Skeleton.SetDrawOrderToSetupPose()`
    - `Skeleton.SetSlotAttachmentsToSetupPose()`
    - `Skeleton.SetSlotAttachmentToSetupPose()`

    with `Skeleton.SetSlotsToSetupPose()`.
    Replace:

    - `Slot.SetColorToSetupPose()`
    - `Slot.SetAttachmentToSetupPose()`

    with `Slot.SetToSetupPose()`.

    Also removed less commonly used extension methods:
    `TrackEntry.AllowImmediateQueue()`, `Animation.SetKeyedItemsToSetupPose()` and `Attachment.IsRenderable()`.

  - **`SkeletonGraphic` now no longer uses a `RawImage` component at each submesh renderer** GameObject when `allowMultipleCanvasRenderers` is true. Instead, a new custom component `SkeletonSubmeshGraphic` is used which is more resource friendly. Replacement of these components will be performed automatically through editor scripting, saving scenes or prefabs will persist the upgrade.
  - **Linear color space:** Previously Slot colors were not displayed the same in Unity as in the Spine Editor. This is now fixed at all shaders, including URP and LWRP shaders. See section _Additions_ below for more details. If you have tweaked Slot colors to look correct in `Linear` color space in Unity but incorrect in Spine, you might want to adjust the tweaked colors. Slot colors displayed in Unity should now match colors displayed in the Spine Editor when configured to display as `Linear` color space in the Spine Editor Settings.
  - **Additive Slots have always been lit** before they were written to the target buffer. Now all lit shaders provide an additional parameter `Light Affects Additive` which defaults to `false`, as it is the more intuitive default value. You can enable the old behaviour by setting this parameter to `true`.
  - **Corrected blending behaviour of all `Sprite` shaders** in `Premultiply Alpha` blend mode (including URP and LWRP packages). Previously vertex color alpha was premultiplied again, even though `Premultiply Alpha` blend mode assumes PMA texture and PMA vertex color input. Slot-alpha blending will thus be correctly lighter after upgrading to 4.0. If you have compensated this problem by disabling `Advanced - PMA Vertex Colors` you can now re-enable this parameter, also allowing for rendering Additive slots in a single pass.
  - **Corrected all `Outline` shaders outline thickness** when `Advanced - Sample 8 Neighbourhood` is disabled (thus using `4 Neighbourhood`). Previously weighting was incorrectly thick (4x as thick) compared to 8 neighbourhood, now it is more consistent. This might require adjustment of all your outline materials where `Sample 8 Neighbourhood` is disabled to restore the previous outline thickness, by adjusting the `Outline Threshold` parameter through adding a `/4` to make the threshold 4 times smaller.
  - Reverted changes: `BoneFollower` property `followLocalScale` has intermediately been renamed to `followScale` but was renamed back to `followLocalScale`. Serialized values (scenes and prefabs) will automatically be upgraded, only code accessing `followScale` needs to be adapted.
  - Fixed Timeline not pausing (and resuming) clip playback on Director pause, this is now the default behaviour. If you require the old behaviour (e.g. to continue playing an idle animation during Director pause), there is now an additional parameter `Don't Pause with Director` provided that can be enabled for each Timeline clip.
  - Fixed Timeline `Spine AnimationState Clips` ignoring empty space on the Timeline after a clip's end. Timeline clips now also offer `Don't End with Clip` and `Clip End Mix Out Duration` parameters if you prefer the old behaviour of previous versions. By default when empty space follows the clip on the timeline, the empty animation is set on the track with a MixDuration of `Clip End Mix Out Duration`. Set `Don't End with Clip` to `true` to continue playing the clip's animation instead and mimic the old 3.8 behaviour. If you prefer pausing the animation instead of mixing out to the empty animation, set `Clip End Mix Out Duration` to a value less than 0, then the animation is paused instead.

- **Additions and Improvements**

  - Additional **Fix Draw Order** parameter at SkeletonRenderer, defaults to `disabled` (previous behaviour).
    Applies only when 3+ submeshes are used (2+ materials with alternating order, e.g. "A B A").
    If `true`, MaterialPropertyBlocks are assigned at each material to prevent aggressive batching of submeshes
    by e.g. the LWRP renderer, leading to incorrect draw order (e.g. "A1 B A2" changed to "A1A2 B").
    You can leave this parameter disabled when everything is drawn correctly to save the additional performance cost.
  - **Additional Timeline features.** SpineAnimationStateClip now provides a `Speed Multiplier`, a start time offset parameter `Clip In`, support for blending successive animations by overlapping tracks. An additional `Use Blend Duration` parameter _(defaults to true)_ allows for automatic synchronisation of MixDuration with the current overlap blend duration. An additional Spine preferences parameter `Use Blend Duration` has been added which can be disabled to default to the previous behaviour before this update.
  - Additional `SpriteMask and RectMask2D` example scene added for demonstration of mask setup and interaction.
  - `Real physics hinge chains` for both 2D and 3D physics. The [SkeletonUtilityBone](https://esotericsoftware.com/spine-unity-utility-components#SkeletonUtilityBone) Inspector provides an interface to create 2D and 3D hinge chains. Previously created chains have only been respecting gravity, but not momentum of the skeleton or parent bones. The new physics rig created when pressing `Create 3D Hinge Chain` and `Create 2D Hinge Chain` creates a more complex setup that also works when flipping the skeleton. Note that the chain root node is no longer parented to bones of the skeleton. This is a requirement in Unity to have momentum applied properly - do not reparent the chain root to bones of your skeleton, or you will loose any momentum applied by the skeleton's movement.
  - `Outline rendering functionality for all shaders.` Every shader now provides an additional set of `Outline` parameters to enable custom outline rendering. When outline rendering is enabled via the `Material` inspector, it automatically switches the shader to the respective `Spine/Outline` shader variant. Outlines are generated by sampling neighbour pixels, so be sure to add enough transparent padding when exporting your atlas textures to fit the desired outline width. In order to enable outline rendering at a skeleton, it is recommended to first prepare an additional outline material copy and then switch the material of the target skeleton to this material. This prevents unnecessary additional runtime material copies and drawcalls. Material switching can be prepared via a [SkeletonRendererCustomMaterials](https://esotericsoftware.com/spine-unity-utility-components#SkeletonRendererCustomMaterials) component and then enabled or disabled at runtime. Alternatively, you can also directly modify the `SkeletonRenderer.CustomMaterialOverride` property.
    Outline rendering is fully supported on `SkeletonGraphic` shaders as well.
  - Added `SkeletonRenderer.EditorSkipSkinSync` scripting API property to be able to set custom skins in editor scripts. Enable this property when overwriting the Skeleton's skin from an editor script. Without setting this parameter, changes will be overwritten by the next inspector update. Only affects Inspector synchronisation of skin with `initialSkinName`, not startup initialization.
  - `AtlasUtilities.GetRepackedAttachments()` and `AtlasUtilities.GetRepackedSkin()` provide support for additional texture channels such as normal maps via the optional parameter `additionalTexturePropertyIDsToCopy `. See the spine-unity runtime documentation, section [Combining Skins - Advanced - Runtime Repacking with Normalmaps](http://esotericsoftware.com/spine-unity#Combining-Skins) for further info and example usage code.
  - `BoneFollower` can now optionally follow (uniform) world scale of the reference bone. There is now a `Mode` dropdown selector in the Inspector which can be set to either `Local` or `World Uniform`.
  - All `Spine/SkeletonGraphic` shaders now provide a parameter `CanvasGroup Compatible` which can be enabled to support `CanvasGroup` alpha blending. For correct results, you should then disable `Pma Vertex Colors` in the `SkeletonGraphic` Inspector, in section `Advanced` (otherwise Slot alpha will be applied twice).
  - **Now supporting Universal Render Pipeline (URP), including the 2D Renderer pipeline, through an additional UPM package.**

    - **Installation:** You can download the Unity Package Manager (UPM) package via the [download page](http://esotericsoftware.com/spine-unity-download) or find it in the [spine-runtimes/spine-unity/Modules](https://github.com/EsotericSoftware/spine-runtimes/tree/3.8-beta/spine-unity/Modules) subdirectory on the git repository. You can then either unzip (copy if using git) the package to

      - a) the `Packages` directory in your project where it will automatically be loaded, or
      - b) to an arbitrary directory outside the Assets directory and then open Package Manager in Unity, select the `+` icon, choose `Add package from disk..` and point it to the package.json file.

      The Project panel should now show an entry `Spine Universal RP Shaders` under `Packages`. If the directory is not yet listed, you will need to close and re-open Unity to have it display the directory and its contents.

    - **Usage:** The package provides two shaders specifically built for the universal render pipeline:
      - `Universal Render Pipeline/Spine/Skeleton`, as a universal variant of the `Spine/Skeleton` shader,
      - `Universal Render Pipeline/Spine/Skeleton Lit`, as a universal variant of the `Spine/Skeleton Lit` shader,
      - `Universal Render Pipeline/Spine/Sprite`, as a universal variant of the `Spine/Sprite/Vertex Lit` and `Pixel Lit` shaders, which were not functioning in the universal render pipeline,
    - `Universal Render Pipeline/2D/Spine/Skeleton Lit`, as a universal 2D Renderer variant of the `Spine/Skeleton Lit` shader, and
      - `Universal Render Pipeline/2D/Spine/Sprite`, as a universal 2D Renderer variant of the `Spine/Sprite/Vertex Lit` and `Pixel Lit` shaders.
        The shaders can be assigned to materials as usual and will respect your settings of the assigned `UniversalRenderPipelineAsset` under `Project Settings - Graphics`.
    - **Restrictions** As all Spine shaders, the URP shaders **do not support `Premultiply alpha` (PMA) atlas textures in Linear color space**. Please export your atlas textures as `straight alpha` textures with disabled `Premultiply alpha` setting when using Linear color space. You can check the current color space via `Project Settings - Player - Other Settings - Color Space.`.
    - **Example:** You can find an example scene in the package under `com.esotericsoftware.spine.urp-shaders-3.8/Examples/URP Shaders.unity` that demonstrates usage of the URP shaders.

  - Spine Preferences now provide an **`Atlas Texture Settings`** parameter for applying customizable texture import settings at all newly imported Spine atlas textures.
    When exporting atlas textures from Spine with `Premultiply alpha` enabled (the default), you can leave it at `PMATexturePreset`. If you have disabled `Premultiply alpha`, set it to the included `StraightAlphaTexturePreset` asset. You can also create your own `TextureImporter` `Preset` asset and assign it here (include `PMA` or `Straight` in the name). In Unity versions before 2018.3 you can use `Texture2D` template assets instead of the newer `Preset` assets. Materials created for imported textures will also have the `Straight Alpha Texture` parameter configured accordingly.
  - All `Sprite` shaders (including URP and LWRP extension packages) now provide an additional `Fixed Normal Space` option `World-Space`. PReviously options were limited to `View-Space` and `Model-Space`.
  - `SkeletonGraphic` now fully supports [`SkeletonUtility`](https://esotericsoftware.com/spine-unity-utility-components#SkeletonUtility) for generating a hierarchy of [`SkeletonUtilityBones`](https://esotericsoftware.com/spine-unity-utility-components#SkeletonUtilityBone) in both modes `Follow` and `Override`. This also enables creating hinge chain physics rigs and using `SkeletonUtilityConstraints` such as `SkeletonUtilityGroundConstraint` and `SkeletonUtilityEyeConstraint` on `SkeletonGraphic`.
  - Added **native support for slot blend modes** `Additive`, `Multiply` and `Screen` with automatic assignment at newly imported skeleton assets. `BlendModeMaterialAssets` are now obsolete and replaced by the native properties at `SkeletonDataAsset`. The `SkeletonDataAsset` Inspector provides a new `Blend Modes - Upgrade` button to upgrade an obsolete `BlendModeMaterialAsset` to the native blend modes properties. This upgrade will be performed automatically on imported and re-imported assets.
  - `BoneFollower` and `BoneFollowerGraphic` components now provide better support for following bones when the skeleton's Transform is not the parent of the follower's Transform. Previously e.g. rotating a common parent Transform did not lead to the desired result, as well as negatively scaling a skeleton's Transform when it is not a parent of the follower's Transform.
  - **Linear color space:** Previously Slot colors were not displayed the same in Unity as in the Spine Editor (when configured to display as `Linear` color space in Spine Editor Settings). This is now fixed at all shaders, including URP and LWRP shaders.
  - All Spine shaders (also including URP and LWRP shaders) now support `PMA Vertex Colors` in combination with `Linear` color space. Thus when using Spine shaders, you should always enable `PMA Vertex Colors` at the `SkeletonRenderer` component. This allows using single pass `Additive` Slots rendering. Note that textures shall still be exported as `Straight alpha` when using `Linear` color space, so combine `PMA Vertex Colors` with `Straight Texture`. All `Sprite` shaders now provide an additional blend mode for this, named `PMA Vertex, Straight Texture` which shall be the preferred Sprite shader blend mode in `Linear` color space.
  - Additive Slots have always been lit before they were written to the target buffer. Now all lit shaders provide an additional parameter `Light Affects Additive` which defaults to `false`, as it is the more intuitive default value. You can enable the old behaviour by setting this parameter to `true`.
  - `SkeletonRootMotion` and `SkeletonMecanimRootMotion` components now support arbitrary bones in the hierarchy as `Root Motion Bone`. Previously there were problems when selecting a non-root bone as `Root Motion Bone`. `Skeleton.ScaleX` and `.ScaleY` and parent bone scale is now respected as well.
  - URP and LWRP `Sprite` and `SkeletonLit` shaders no longer require `Advanced - Add Normals` enabled to properly cast and receive shadows. It is recommended to disable `Add Normals` if normals are otherwise not needed.
  - Added an example component `RootMotionDeltaCompensation` located in `Spine Examples/Scripts/Sample Components` which can be used for applying simple delta compensation. You can enable and disable the component to toggle delta compensation of the currently playing animation on and off.
  - `SkeletonRagdoll` and `SkeletonRagdoll2D` now support bone scale at any bone in the skeleton hierarchy. This includes negative scale and root bone scale.
  - `Attachment.GetRemappedClone(Sprite)` method now provides an additional optional parameter `useOriginalRegionScale`. When set to `true`, the replaced attachment's scale is used instead of the Sprite's `Pixel per Unity` setting, allowing for more consistent scaling. _Note:_ When remapping Sprites, be sure to set the Sprite's `Mesh Type` to `Full Rect` and not `Tight`, otherwise the scale will be wrong.
  - `SkeletonGraphic` now **supports all Slot blend modes** when `Advanced - Multiple Canvas Renderers` is enabled in the Inspector. The `SkeletonGraphic` Inspector now provides a `Blend Mode Materials` section where you can assign `SkeletonGraphic` materials for each blend mode, or use the new default materials. New `SkeletonGraphic` shaders and materials have been added for each blend mode. The `BlendModes.unity` example scene has been extended to demonstrate this new feature. For detailed information see the [`SkeletonGraphic documentation page`](http://esotericsoftware.com/spine-unity#Parameters).
  - Timeline clips now also offer `Don't End with Clip` and `Clip End Mix Out Duration` parameters. By default when empty space follows the clip on the timeline, the empty animation is set on the track with a MixDuration of `Clip End Mix Out Duration`. Set `Don't End with Clip` to `true` to continue playing the clip's animation instead and mimic the old 3.8 behaviour. If you prefer pausing the animation instead of mixing out to the empty animation, set `Clip End Mix Out Duration` to a value less than 0, then the animation is paused instead.
  - Prefabs containing `SkeletonRenderer`, `SkeletonAnimation` and `SkeletonMecanim` now provide a proper Editor preview, including the preview thumbnail.
  - `SkeletonRenderer` (and subclasses`SkeletonAnimation` and `SkeletonMecanim`) now provide a property `Advanced - Fix Prefab Override MeshFilter`, which when enabled fixes the prefab always being marked as changed. It sets the MeshFilter's hide flags to `DontSaveInEditor`. Unfortunately this comes at the cost of references to the `MeshFilter` by other components being lost, therefore this parameter defaults to `false` to keep the safe existing behaviour.
  - `BoundingBoxFollower` and `BoundingBoxFollowerGraphic` now provide previously missing `usedByEffector` and `usedByComposite` parameters to be set at all generated colliders.
  - `BoneFollower` and `BoneFollowerGraphic` now provide an additional `Follow Parent World Scale` parameter to allow following simple scale of parent bones (rotated/skewed scale can't be supported).
  - Improved `Advanced - Fix Prefab Override MeshFilter` property for `SkeletonRenderer` (and subclasses`SkeletonAnimation` and `SkeletonMecanim`), now providing an additional option to use a global value which can be set in `Edit - Preferences - Spine`.
  - Timeline naming improvements: `Spine AnimationState Clip` Inspector parameter `Custom Duration` changed and inverted to `Default Mix Duration` for more clarity. Shortened all Timeline add track menu entries from: `Spine.Unity.Playables - <track type>` to `Spine - <track type>`, `Spine Animation State Track` to `SkeletonAnimation Track`, `Spine AnimationState Graphic Track` to `SkeletonGraphic Track`, and `Spine Skeleton Flip Track` to `Skeleton Flip Track`.
  - Timeline track appearance and Inspector: Tracks now show icons and track colors to make them easier to distinguish. When a Track is selected, the Inspector now shows an editable track name which was previously only editable at the Timeline asset.
  - Added example component `SkeletonRenderTexture` to render a `SkeletonRenderer` to a `RenderTexture`, mainly for proper transparency. Added an example scene named `RenderTexture FadeOut Transparency` that demonstrates usage for a fadeout transparency effect.
  - Added another fadeout example component named `SkeletonRenderTextureFadeout` which takes over transparency fadeout when enabled. You can use this component as-is, attach it in disabled state and enable it to start a fadeout effect.
  - Timeline clips now offer an additional `Alpha` parameter for setting a custom constant mix alpha value other than 1.0, just as `TrackEntry.Alpha`. Defaults to 1.0.
  - `SkeletonGraphic` now provides additional render callback delegates `OnInstructionsPrepared`, `AssignMeshOverrideSingleRenderer` and `AssignMeshOverrideMultipleRenderers`. `OnInstructionsPrepared` is raised at the end of LateUpdate after render instructions are done, target renderers are prepared, and the mesh is ready to be generated. The two `AssignMeshOverride` delegates allow separate code to take over mesh and material assignment of a `SkeletonGraphic` component.
  - Added example component `SkeletonGraphicRenderTexture` to render a `SkeletonGraphic` to a `RenderTexture` (similar as `SkeletonRenderTexture`), mainly for proper transparency. Extended example scene `RenderTexture FadeOut Transparency` accordingly.

- **Changes of default values**

- **Deprecated**

- **Restructuring (Non-Breaking)**

### XNA/MonoGame

- Added normalmap support via `SpineEffectNormalmap` and support for loading multiple texture layers following a suffix-pattern. Please see the example code on how to use them.
- Added `Z` property to `SkeletonRenderer` to provide a constant Z offset that's added to all vertices.
- Added `ZSpacing` property to `SkeletonRenderer` to allow specifying the distance on the z-axis between attachments.
- SkeletonDebugRenderer bone color attributes are now public and modifiable by user.

## Java

- Timeline API has been extended to support component-wise timelines exported by Spine 4.0.
- Added `AnimationState.clearNext()` which removes the given `TrackEntry` and all entries after it.
- Added support for texture atlas key value pairs, see `Region.names` and `Region.values`.
- Added support for reverse animation playback via `TrackEntry.getReverse()` and `TrackEntry.setReverse()`.
- Added proportional spacing mode support for path constraints.
- Added support for uniform scaling for two bone IK.
- Fixed applying a constraint reverting changes from other constraints.
- **Breaking change:** Removed `SkeletonData` and `Skeleton` methods: `findBoneIndex`, `findSlotIndex`. Bones and slots have an `index` field that should be used instead.

### libGDX

- Exposed colors in `SkeletonRendererDebug`.
- Updated to libGDX 1.10.0.

## Lua

- Expose non-essential colors on bones, bounding box, clipping, and path attachments.
- Timeline API has been extended to support component-wise timelines exported by Spine 4.0.
- Added `AnimationState.clearNext()` which removes the given `TrackEntry` and all entries after it.
- Added support for texture atlas key value pairs, see `AtlasRegion.names` and `AtlasRegion.values`.
- Added support for reverse animation playback via `TrackEntry.reverse`.
- Added proportional spacing mode support for path constraints.
- Added support for uniform scaling for two bone IK.
- Fixed applying a constraint reverting changes from other constraints.

### Love2D

### Corona

- **Breaking change:** spine-corona has been renamed to spine-solar2d. Change your `require "spine-corona.spine"` statements to `require "spine-solar2d.spine"`

## Typescript/Javascript

- **Breaking change:** refactored to ECMAScript modules. See this [blog post](http://esotericsoftware.com/blog/spine-goes-npm) as well as the updated [README.md](spine-ts/README.md).
- **Breaking change:** the `build/` folder and compiled artifacts are no longer part of the repository. Instead, `npm run build` in `spine-ts/` to generate ECMAScript modules and IIFE modules in `spine-<module-name>/dist`.
- **Breaking change:** the `.npmignore` and `package.json` files in the root directory have been deleted. Use the corresponding files in `spine-ts/` instead, or better, depend on the packages from the NPM registry.
- Updated runtime to be compatible with TypeScript 3.6.3.
- Added `AssetManager#setRawDataURI(path, data)`. Allows to set raw data URIs for a specific path, which in turn enables embedding assets into JavaScript/HTML.
- Expose non-essential colors on bones, bounding box, clipping, and path attachments.
- Timeline API has been extended to support component-wise timelines exported by Spine 4.0.
- Added `AnimationState.clearNext()` which removes the given `TrackEntry` and all entries after it.
- Added support for texture atlas key value pairs, see `AtlasRegion.names` and `AtlasRegion.values`.
- Added support for reverse animation playback via `TrackEntry.reverse`.
- Added proportional spacing mode support for path constraints.
- Added support for uniform scaling for two bone IK.
- Fixed applying a constraint reverting changes from other constraints.
- `AssetManager` constructor now takes an option `Downloader` instance. Used to download assets only once and share them between `AssetManager` instances.
- Added web worker support to `AssetManager`.
- Added various default parameters to `AnimationState` methods for ease of use.
- Added `SpineCanvas`, a simpler way to render a scene via spine-webgl. See `spine-ts/spine-webgl/examples/barebones.html` and `spine-ts/spine-webgl/examples/mix-and-match.html`.

### WebGL backend

- **Breaking change:** removed `SharedAssetManager`. Use `AssetManager` with a shared `Downloader` instance instead.
- **Breaking change:** the global object `spine.webgl` no longer exists. All classes and functions are now exposed on the global `spine` object directly. Simply replace any reference to `spine.webgl.` in your source code with `spine.`.

### Canvas backend

- Renderer now accounts for whitespace stripping.
- **Breaking change:** the global object `spine.canvas` no longer exists. All classes and functions are now exposed on the global `spine` object directly. Simply replace any reference to `spine.canvas.` in your source code with `spine.`.

### Three.js backend

- `SkeletonMesh` now takes an optional `SkeletonMeshMaterialParametersCustomizer` function that allows you to modify the `ShaderMaterialParameters` before the material is finalized. Use it to modify things like THREEJS' `Material.depthTest` etc. See #1590.
- **Breaking change:** the global object `spine.canvas` no longer exists. All classes and functions are now exposed on the global `spine` object directly. Simply replace any reference to `spine.threejs.` in your source code with `spine.`.
- **Breaking change:** the default fragment shader of `SkeletonMeshMaterial` now explicitely discards fragments with alpha < 0.5. See https://github.com/EsotericSoftware/spine-runtimes/issues/1985
- **Breaking change:** reversal of the previous breaking change: the default fragment shader of `SkeletonMeshMaterial` does no longer discard fragments with alpha < 0.5. Pass a `SkeletonMeshMaterialParametersCustomizer` to the `SkeletonMesh` constructor, and modify `parameters.alphaTest` to be > 0.

### Player

- Added `SpinePlayerConfig.rawDataURIs`. Allows to embed data URIs for skeletons, atlases and atlas page images directly in the HTML/JS without needing to load it from a separate file. See the example for a demonstration.
- Added `SpinePlayerConfig.frame`. If set, the callback is called each frame, before the skeleton is posed or drawn.
- Added `SpinePlayerConfig.update`. If set, the callback is called each frame, just after the skeleton is posed.
- Added `SpinePlayerConfig.draw`. If set, the callback is called each frame, just after the skeleton is drawn.
- Added `SpinePlayerConfig.downloader`. The `spine.Downloader` instance can be shared between players so assets are only downloaded once.
- If `SpinePlayerConfig.jsonURL` ends with an anchor, the anchor text is used to find the skeleton in the specified JSON file.
- Added `SpinePlayer.dispose()`, disposes all CPU and GPU side resources, removes all listeners, and removes the player DOM from the parent.

# 3.8

## AS3

- **Breaking changes**

  - Renamed `Slot#getAttachmentVertices()` to `Slot#getDeform()`.
  - Changed the `.json` curve format and added more assumptions for omitted values, reducing the average size of JSON exports.
  - Renamed `Skin#addAttachment()` to `Skin#setAttachment()`.
  - Removed `VertexAttachment#applyDeform()` and replaced it with `VertexAttachment#deformAttachment`. The attachment set on this field is used to decide if a `DeformTimeline` should be applied to the attachment active on the slot to which the timeline is applied.
  - Removed `inheritDeform` field, getter, and setter from `MeshAttachment`.
  - Changed `.skel` binary format, added a string table. References to strings in the data resolve to this string table, reducing storage size of binary files considerably.
  - Changed the `.json` and `.skel` file formats to accomodate the new feature and file size optimiations. Old projects must be exported with Spine 3.8.20+ to be compatible with the 3.8 Spine runtimes.
  - Switched projects from FDT to Visual Studio Code. See updated `README.md` files for instructions.

- **Additions**
  - Added `SkeletonBinary` to load binary `.skel` files. See `MixAndMatchExample.as` in `spine-startling-example`.
  - Added `x` and `y` coordinates for setup pose AABB in `SkeletonData`.
  - Added support for rotated mesh region UVs.
  - Added skin-specific bones and constraints which are only updated if the skeleton's current skin contains them.
  - Improved Skin API to make it easier to handle mix-and-match use cases.
    - Added `Skin#getAttachments()`. Returns all attachments in the skin.
    - Added `Skin#getAttachments(int slotIndex)`. Returns all attachements in the skin for the given slot index.
    - Added `Skin#addSkin(Skin skin)`. Adds all attachments, bones, and skins from the specified skin to this skin.
    - Added `Skin#copySkin(Skin skin)`. Adds all attachments, bones, and skins from the specified skin to this skin. `VertexAttachment` are shallowly copied and will retain any parent mesh relationship. All other attachment types are deep copied.
  - Added `Attachment#copy()` to all attachment type implementations. This lets you deep copy an attachment to modify it independently from the original, i.e. when programmatically changing texture coordinates or mesh vertices.
  - Added `MeshAttachment#newLinkedMesh()`, creates a linked mesh linkted to either the original mesh, or the parent of the original mesh.
  - Added IK softness.

### Starling

- Added `MixAndMatchExample.as` to demonstrate the new Skin API additions and how to load binary `.skel` files.
- Switched projects from FDT to Visual Studio Code. See updated `README.md` files for instructions.

## C

- **Breaking changes**

  - Renamed `spSlot#attachmentVertices` to `spSlot#deform`.
  - Changed the `.json` curve format and added more assumptions for omitted values, reducing the average size of JSON exports.
  - Renamed `spSkin_addAttachment()` to `Skin#spSkin_addAttachment()`.
  - Removed `spVertexAttachment_applyDeform()` and replaced it with `VertexAttachment#deformAttachment`. The attachment set on this field is used to decide if a `spDeformTimeline` should be applied to the attachment active on the slot to which the timeline is applied.
  - Removed `inheritDeform` field, getter, and setter from `spMeshAttachment`.
  - Changed `.skel` binary format, added a string table. References to strings in the data resolve to this string table, reducing storage size of binary files considerably.
  - Changed the `.json` and `.skel` file formats to accomodate the new feature and file size optimiations. Old projects must be exported with Spine 3.8.20+ to be compatible with the 3.8 Spine runtimes.

- **Additions**
  - Added `x` and `y` coordinates for setup pose AABB in `spSkeletonData`.
  - Added support for rotated mesh region UVs.
  - Added skin-specific bones and constraints which are only updated if the skeleton's current skin contains them.
  - Improved Skin API to make it easier to handle mix-and-match use cases.
    - Added `spSkin_getAttachments()`. Returns all attachments in the skin.
    - Added `spSkin_getAttachments(int slotIndex)`. Returns all attachements in the skin for the given slot index.
    - Added `spSkin_addSkin(spSkin* skin)`. Adds all attachments, bones, and skins from the specified skin to this skin.
    - Added `spSkin_copySkin(spSkin* skin)`. Adds all attachments, bones, and skins from the specified skin to this skin. `spVertexAttachment` are shallowly copied and will retain any parent mesh relationship. All other attachment types are deep copied.
    - All attachments inserted into skins are reference counted. When the last skin referencing an attachment is disposed, the attachment will also be disposed.
  - Added `spAttachment_copy()` to all attachment type implementations. This lets you deep copy an attachment to modify it independently from the original, i.e. when programmatically changing texture coordinates or mesh vertices.
  - Added `spMeshAttachment_newLinkedMesh()`, creates a linked mesh linkted to either the original mesh, or the parent of the original mesh.
  - Added IK softness.

### Cocos2d-Objc

- Added mix-and-match example to demonstrate the new Skin API.
- Added `IKExample`.
- Added `SkeletonAnimation preUpdateWorldTransformsListener` and `SkeletonAnimation postUpdateWorldTransformsListener`. When set, these callbacks will be invokved before and after the skeleton's `updateWorldTransforms()` method is called. See the `IKExample` how it can be used.

### SFML

- Added mix-and-match example to demonstrate the new Skin API.
- Added `IKExample`.

## C++

- **Breaking Changes**

  - Renamed `Slot::getAttachmentVertices()` to `Slot::getDeform()`.
  - Changed the `.json` curve format and added more assumptions for omitted values, reducing the average size of JSON exports.
  - Renamed `Skin::addAttachment()` to `Skin::setAttachment()`.
  - Removed `VertexAttachment::applyDeform()` and replaced it with `VertexAttachment::getDeformAttachment()`. The attachment set on this field is used to decide if a `DeformTimeline` should be applied to the attachment active on the slot to which the timeline is applied.
  - Removed `_inheritDeform` field, getter, and setter from `MeshAttachment`.
  - Changed `.skel` binary format, added a string table. References to strings in the data resolve to this string table, reducing storage size of binary files considerably.
  - Changed the `.json` and `.skel` file formats to accomodate the new feature and file size optimiations. Old projects must be exported with Spine 3.8.20+ to be compatible with the 3.8 Spine runtimes.

- **Additions**
  - `AnimationState` and `TrackEntry` now also accept a subclass of `AnimationStateListenerObject` as a listener for animation events in the overloaded `setListener()` method.
  - `SkeletonBinary` and `SkeletonJson` now parse and set all non-essential data like audio path.
  - Added `x` and `y` coordinates for setup pose AABB in `SkeletonData`.
  - Added support for rotated mesh region UVs.
  - Added skin-specific bones and constraints which are only updated if the skeleton's current skin contains them.
  - Improved Skin API to make it easier to handle mix-and-match use cases.
    - Added `Skin#getAttachments()`. Returns all attachments in the skin.
    - Added `Skin#getAttachments(int slotIndex)`. Returns all attachements in the skin for the given slot index.
    - Added `Skin#addSkin(Skin &skin)`. Adds all attachments, bones, and skins from the specified skin to this skin.
    - Added `Skin#copySkin(Skin &skin)`. Adds all attachments, bones, and skins from the specified skin to this skin. `VertexAttachment` are shallowly copied and will retain any parent mesh relationship. All other attachment types are deep copied.
    - All attachments inserted into skins are reference counted. When the last skin referencing an attachment is disposed, the attachment will also be disposed.
  - Added `Attachment#copy()` to all attachment type implementations. This lets you deep copy an attachment to modify it independently from the original, i.e. when programmatically changing texture coordinates or mesh vertices.
  - Added `MeshAttachment#newLinkedMesh()`, creates a linked mesh linkted to either the original mesh, or the parent of the original mesh.
  - Added IK softness.
  - Exposed `x` and `y` on `SkeletonData` through getters and setters.

### Cocos2d-x

- Updated to cocos2d-x 3.17.1
- Added mix-and-match example to demonstrate the new Skin API.
- Exmaple project requires Visual Studio 2019 on Windows
- Added `IKExample`.
- Added `SkeletonAnimation::setPreUpdateWorldTransformsListener()` and `SkeletonAnimation::setPreUpdateWorldTransformsListener()`. When set, these callbacks will be invokved before and after the skeleton's `updateWorldTransforms()` method is called. See the `IKExample` how it can be used.

### SFML

- Added mix-and-match example to demonstrate the new Skin API.

### UE4

- Added `bAutoPlaying` flag to `USpineSkeletonAnimationComponent`. When `false`, the component will not update the internal animation state and skeleton.
- Updated example project to UE 4.22.
- (Re-)Importing Spine assets will perform a version compatibility check and alert users about mismatches in editor mode.
- `USpineSkeletonRendererComponent` allows passing a `USpineSkeletonComponent` to update it. This way, the renderer component can be used without a skeleton component on the same actor.
- Added blueprint-callable methods to `SpineSkeletonComponent` and `SpineSkeletonAnimationComponent` to query and set skins, and enumerate bones, slots, and animations.
- Extended skeleton data editor preview. The preview now shows bones, slots, animations, and skins found in the skeleton data. See this [blog post](http://esotericsoftware.com/blog/Unreal-Engine-4-quality-of-life-improvements).
- Added preview animation and skin fields, allowing you to preview animations and skins right in the editor. See this [blog post](http://esotericsoftware.com/blog/Unreal-Engine-4-quality-of-life-improvements).
- Removed dependency on `RHI`, `RenderCore`, and `ShaderCore`.
- Re-importing atlases and their textures now works consistently in all situations.
- Added mix-and-match example to demonstrate the new Skin API.
- Materials on `SkeletonRendererComponent` are now blueprint read and writeable. This allows setting dynamic material instances at runtime.
- Added `InitialSkin` property to `USpineWidget`. This allows previewing different skins in the UMG Designer. Initial skins can still be overridden via blueprint events such as `On Initialized`.
- `USpineWidget` will now report its own desired size based on the setup pose dimensions of the skeleton. This is used when selecting `Size to content` on a `USpineWidget` in the designer.
- Updated example project to UE 5.2.

## C#

- **Breaking changes**

  - **Changed `IkConstraintData.Bones` type from `List<BoneData>` to `ExposedList<BoneData>`** for unification reasons. _Note: this modification will most likely not affect user code._
  - Renamed `Slot.AttachmentVertices` to `Slot.Deform`.
  - Changed the `.json` curve format and added more assumptions for omitted values, reducing the average size of JSON exports.
  - Renamed `Skin.AddAttachment()` to `Skin.SetAttachment()`.
  - Removed `FindAttachmentsForSlot(int slotIndex, List<Attachment> attachments)` and `FindNamesForSlot (int slotIndex, List<string> names)` and replaced it with `Skin.GetAttachments(int slotIndex, List<SkinEntry> attachments)` which returns the combined `SkinEntry` object holding both name and attachment.
  - Removed `VertexAttachment.ApplyDeform()` and replaced it with `VertexAttachment.DeformAttachment`. The attachment set on this field is used to decide if a `DeformTimeline` should be applied to the attachment active on the slot to which the timeline is applied.
  - Removed `inheritDeform` field, getter, and setter from `MeshAttachment`.
  - Changed `.skel` binary format, added a string table. References to strings in the data resolve to this string table, reducing storage size of binary files considerably.
  - Changed the `.json` and `.skel` file formats to accomodate the new feature and file size optimiations. Old projects must be exported with Spine 3.8.20+ to be compatible with the 3.8 Spine runtimes.

- **Additions**
  - Added `x` and `y` coordinates for setup pose AABB in `SkeletonData`.
  - Added support for rotated mesh region UVs.
  - Added skin-specific bones and constraints which are only updated if the skeleton's current skin contains them.
  - Improved Skin API to make it easier to handle mix-and-match use cases.
    - Added `Skin.GetAttachments()`. Returns all attachments in the skin.
    - Added `Skin.GetAttachments(int slotIndex, List<SkinEntry> attachments)`. Returns all attachements in the skin for the given slot index. This method replaces `FindAttachmentsForSlot` and `FindNamesForSlot`.
    - Added `Skin.AddSkin(Skin skin)`. Adds all attachments, bones, and skins from the specified skin to this skin.
    - Added `Skin.CopySkin(Skin skin)`. Adds all attachments, bones, and skins from the specified skin to this skin. `VertexAttachment` are shallowly copied and will retain any parent mesh relationship. All other attachment types are deep copied.
  - Added `Attachment.Copy()` to all attachment type implementations. This lets you deep copy an attachment to modify it independently from the original, i.e. when programmatically changing texture coordinates or mesh vertices.
  - Added `MeshAttachment.NewLinkedMesh()`, creates a linked mesh linkted to either the original mesh, or the parent of the original mesh.
  - Added IK softness.

### Unity

- **Breaking changes**

  - **Officially supported Unity versions are 2017.1-2020.2**.
  - **Spine `.asmdef` files are again active by default**. They have previously been deactivated to `.txt` extension which is now no longer necessary.
  - **Removed PoseSkeleton() and PoseWithAnimation()** extension methods to prevent issues where animations are not mixed out. Problem was that these methods did not set AnimationState, leaving incorrect state at e.g. attachments enabled at slots when starting subsequent animations. As a replacement you can use `AnimationState.ClearTrack(0);` followed by `var entry = AnimationState.SetAnimation(0, animation, loop); entry.TrackTime = time` to achieve similar behaviour.
  - **The `Shadow alpha cutoff` shader parameter is now respecting slot-color alpha** values at all Spine shaders. A fragment's texture color alpha is multiplied with slot-color alpha before the result is tested against the `Shadow alpha cutoff` threshold.
  - **Removed redundant `Attachment.GetClone()` and `MeshAttachment.GetLinkedClone()` extension methods**. Use methods `Attachment.Copy` and `MeshAttachment.NewLinkedMesh()` instead.
  - **Renamed extension method `Attachment.GetClone(bool cloneMeshesAsLinked)` to `Attachment.GetCopy(bool cloneMeshesAsLinked)`** to follow the naming scheme of the Spine API.
  - `SkeletonDataAsset.atlasAssets` is now an array of the base class `AtlasAssetBase` instead of `SpineAtlasAsset`, which provides `IEnumerable<> Materials` instead of `List<> materials`. Replace any access via `atlasAsset.materials[0]` with `atlasAsset.Materials.First()` and add a `using System.Linq;` statement.
  - **Changed `MeshAttachment.GetLinkedMesh()` method signatures:** removed optional parameters `bool inheritDeform = true, bool copyOriginalProperties = false`.
  - Changed namespace `Spine.Unity.Modules` to `Spine.Unity` and `Spine.Unity.Examples` after restructuring (see section below) in respective classes:
    - When receiving namespace related errors, replace using statements of `using Spine.Unity.Modules.AttachmentTools;` with `using Spine.Unity.AttachmentTools;`. You can remove `using Spine.Unity.Modules;` statements when a `using Spine.Unity` statement is already present in the file.
    - `AttachmentTools`, `SkeletonPartsRenderer`, `SkeletonRenderSeparator`, `SkeletonRendererCustomMaterials` changed to namespace `Spine.Unity`.
    - `SkeletonGhost`, `SkeletonGhostRenderer`, `AtlasRegionAttacher`, `SkeletonGraphicMirror`, `SkeletonRagdoll`, `SkeletonRagdoll2D`, `SkeletonUtilityEyeConstraint`, `SkeletonUtilityGroundConstraint`, `SkeletonUtilityKinematicShadow` changed to namespace `Spine.Unity.Examples`.
  - Split `Editor/Utility/SpineEditorUtilities` class into multiple files with partial class qualifier.
    - Nested classes `SpineEditorUtilities.AssetUtility` and `SpineEditorUtilities.EditorInstantiation` are now no longer nested. If you receive namespace related errors, replace any occurrance of
      - `SpineEditorUtilities.AssetUtility` with `AssetUtility` and
      - `SpineEditorUtilities.EditorInstantiation` with `EditorInstantiation`.
  - **Timeline Support has been moved to a separate UPM Package** Previously the Spine Timeline integration was located in the `Modules/Timeline` directory and was deactivated by default, making it necessary to activate it via the Spine Preferences. Now the Timeline integration has been moved to an additional UPM package which can be found under `Modules/com.esotericsoftware.spine.timeline`.
  - **Installation:** You can download the Unity Package Manager (UPM) package via the [download page](http://esotericsoftware.com/spine-unity-download) or find it in the [spine-runtimes/spine-unity/Modules](https://github.com/EsotericSoftware/spine-runtimes/tree/3.8-beta/spine-unity/Modules) subdirectory on the git repository. You can then either unzip (copy if using git) the package to
    a) the `Packages` directory in your project where it will automatically be loaded, or
    b) to an arbitrary directory outside the Assets directory and then open Package Manager in Unity, select the `+` icon, choose `Add package from disk..` and point it to the package.json file.
    The Project panel should now show an entry `Spine Timeline Extensions` under `Packages`. If the directory is not yet listed, you will need to close and re-open Unity to have it display the directory and its contents.
  - `SkeletonMecanim`'s `Layer Mix Mode` enum name `MixMode.SpineStyle` has been renamed to `MixMode.Hard`. This is most likely not set via code and thus unlikely to be a problem. Serialized scenes and prefabs are unaffected.
  - `SkeletonRootMotion` and `SkeletonMecanimRootMotion` components now support arbitrary bones in the hierarchy as `Root Motion Bone`. Previously there were problems when selecting a non-root bone as `Root Motion Bone`. `Skeleton.ScaleX` and `.ScaleY` and parent bone scale is now respected as well.

- **Additions**

  - **Spine Preferences stored in Assets/Editor/SpineSettings.asset** Now Spine uses the new `SettingsProvider` API, storing settings in a SpineSettings.asset file which can be shared with team members. Your old preferences are automatically migrated to the new system.
  - Added support for Unity's SpriteMask to `SkeletonAnimation` and `SkeletonMecanim`. All mask interaction modes are supported. See this [blog post](http://esotericsoftware.com/blog/Unity-SpriteMask-and-RectMask2D-support).
  - Added support for Unity's RectMask2D to SkeletonGraphics. See this [blog post](http://esotericsoftware.com/blog/Unity-SpriteMask-and-RectMask2D-support).
  - Added `Create 2D Hinge Chain` button at `SkeletonUtilityBone` inspector, previously only `Create 3D Hinge Chain` was available.
  - **Now supporting Lightweight Render Pipeline (LWRP) through an additional UPM package.**

    - **Installation:** You can download the Unity Package Manager (UPM) package via the [download page](http://esotericsoftware.com/spine-unity-download) or find it in the [spine-runtimes/spine-unity/Modules](https://github.com/EsotericSoftware/spine-runtimes/tree/3.8-beta/spine-unity/Modules) subdirectory on the git repository. You can then either unzip (copy if using git) the package to

      - a) the `Packages` directory in your project where it will automatically be loaded, or
      - b) to an arbitrary directory outside the Assets directory and then open Package Manager in Unity, select the `+` icon, choose `Add package from disk..` and point it to the package.json file.

      > If you are using git and Unity 2019.2 or newer versions and receive an error that dependencies could not be resolved by the package manager (only higher versions of Unity's `Lightweight RP` package are available, e.g. `6.9.0` and up), please copy the prepared package-UNITYVERSION.json file for your Unity version (e.g. `package-2019.2.json`) over the existing package.json file to change the dependency accordingly. Unfortunately Unity's Package Manager does not provide a way to specify a version range for a dependency like "5.7.2 - 6.9.0" yet, so this manual step is necessary for git users.

      The Project panel should now show an entry `Spine Lightweight RP Shaders` under `Packages`. If the directory is not yet listed, you will need to close and re-open Unity to have it display the directory and its contents.

    - **Usage:** The package provides two shaders specifically built for the lightweight render pipeline:
      - `Lightweight Render Pipeline/Spine/Skeleton`, as a lightweight variant of the `Spine/Skeleton` shader,
      - `Lightweight Render Pipeline/Spine/Skeleton Lit`, as a lightweight variant of the `Spine/Skeleton Lit` shader and
      - `Lightweight Render Pipeline/Spine/Sprite`, as a lightweight variant of the `Spine/Sprite/Vertex Lit` and `Pixel Lit` shaders, which were not functioning in the lightweight render pipeline. The shaders can be assigned to materials as usual and will respect your settings of the assigned `LightweightRenderPipelineAsset` under `Project Settings - Graphics`.
    - **Restrictions** As all Spine shaders, the LWRP shaders **do not support `Premultiply alpha` (PMA) atlas textures in Linear color space**. Please export your atlas textures as `straight alpha` textures with disabled `Premultiply alpha` setting when using Linear color space. You can check the current color space via `Project Settings - Player - Other Settings - Color Space.`.
    - **Example:** You can find an example scene in the package under `com.esotericsoftware.spine.lwrp-shaders-3.8/Examples/LWRP Shaders.unity` that demonstrates usage of the LWRP shaders.

  - Added `Spine/Skeleton Lit ZWrite` shader. This variant of the `Spine/Skeleton Lit` shader writes to the depth buffer with configurable depth alpha threshold. Apart from that it is identical to `Spine/Skeleton Lit`.
  - Additional yield instructions to wait for animation track events `End`, `Complete` and `Interrupt`.
    - `WaitForSpineAnimationComplete` now proves an additional `bool includeEndEvent` parameter, defaults to `false` (previous behaviour).
    - Added a new `WaitForSpineAnimationEnd` yield instruction.
    - Added a new generic `WaitForSpineAnimation` yield instruction which can be configured to wait for any combination of animation track events. It is now used as base class for `WaitForSpineAnimationComplete` and `WaitForSpineAnimationEnd`.
  - Additional **Fix Draw Order** parameter at SkeletonRenderer, defaults to `disabled` (previous behaviour).
    Applies only when 3+ submeshes are used (2+ materials with alternating order, e.g. "A B A").
    If true, MaterialPropertyBlocks are assigned at each material to prevent aggressive batching of submeshes
    by e.g. the LWRP renderer, leading to incorrect draw order (e.g. "A1 B A2" changed to "A1A2 B").
    You can leave this parameter disabled when everything is drawn correctly to save the additional performance cost.
  - **Additional Timeline features.** SpineAnimationStateClip now provides a `Speed Multiplier`, a start time offset parameter `Clip In`, support for blending successive animations by overlapping tracks. An additional `Use Blend Duration` parameter _(defaults to true)_ allows for automatic synchronisation of MixDuration with the current overlap blend duration. An additional Spine preferences parameter `Use Blend Duration` has been added which can be disabled to default to the previous behaviour before this update.
  - Additional `SpriteMask and RectMask2D` example scene added for demonstration of mask setup and interaction.
  - `Real physics hinge chains` for both 2D and 3D physics. The [SkeletonUtilityBone](https://esotericsoftware.com/spine-unity-utility-components#SkeletonUtilityBone) Inspector provides an interface to create 2D and 3D hinge chains. Previously created chains have only been respecting gravity, but not momentum of the skeleton or parent bones. The new physics rig created when pressing `Create 3D Hinge Chain` and `Create 2D Hinge Chain` creates a more complex setup that also works when flipping the skeleton. Note that the chain root node is no longer parented to bones of the skeleton. This is a requirement in Unity to have momentum applied properly - do not reparent the chain root to bones of your skeleton, or you will loose any momentum applied by the skeleton's movement.
  - `Outline rendering functionality for all shaders.` Every shader now provides an additional set of `Outline` parameters to enable custom outline rendering. When outline rendering is enabled via the `Material` inspector, it automatically switches the shader to the respective `Spine/Outline` shader variant. Outlines are generated by sampling neighbour pixels, so be sure to add enough transparent padding when exporting your atlas textures to fit the desired outline width. In order to enable outline rendering at a skeleton, it is recommended to first prepare an additional outline material copy and then switch the material of the target skeleton to this material. This prevents unnecessary additional runtime material copies and drawcalls. Material switching can be prepared via a [SkeletonRendererCustomMaterials](https://esotericsoftware.com/spine-unity-utility-components#SkeletonRendererCustomMaterials) component and then enabled or disabled at runtime. Alternatively, you can also directly modify the `SkeletonRenderer.CustomMaterialOverride` property.
    Outline rendering is fully supported on `SkeletonGraphic` shaders as well.
  - Added `SkeletonRenderer.EditorSkipSkinSync` scripting API property to be able to set custom skins in editor scripts. Enable this property when overwriting the Skeleton's skin from an editor script. Without setting this parameter, changes will be overwritten by the next inspector update. Only affects Inspector synchronisation of skin with `initialSkinName`, not startup initialization.
  - All `Spine/SkeletonGraphic` shaders now provide a parameter `CanvasGroup Compatible` which can be enabled to support `CanvasGroup` alpha blending. For correct results, you should then disable `Pma Vertex Colors` in the `SkeletonGraphic` Inspector, in section `Advanced` (otherwise Slot alpha will be applied twice).
  - **Now supporting Universal Render Pipeline (URP), including the 2D Renderer pipeline, through an additional UPM package.**

    - **Installation:** You can download the Unity Package Manager (UPM) package via the [download page](http://esotericsoftware.com/spine-unity-download) or find it in the [spine-runtimes/spine-unity/Modules](https://github.com/EsotericSoftware/spine-runtimes/tree/3.8-beta/spine-unity/Modules) subdirectory on the git repository. You can then either unzip (copy if using git) the package to

      - a) the `Packages` directory in your project where it will automatically be loaded, or
      - b) to an arbitrary directory outside the Assets directory and then open Package Manager in Unity, select the `+` icon, choose `Add package from disk..` and point it to the package.json file.

      The Project panel should now show an entry `Spine Universal RP Shaders` under `Packages`. If the directory is not yet listed, you will need to close and re-open Unity to have it display the directory and its contents.

    - **Usage:** The package provides two shaders specifically built for the universal render pipeline:
      - `Universal Render Pipeline/Spine/Skeleton`, as a universal variant of the `Spine/Skeleton` shader,
      - `Universal Render Pipeline/Spine/Skeleton Lit`, as a universal variant of the `Spine/Skeleton Lit` shader,
      - `Universal Render Pipeline/Spine/Sprite`, as a universal variant of the `Spine/Sprite/Vertex Lit` and `Pixel Lit` shaders, which were not functioning in the universal render pipeline,
    - `Universal Render Pipeline/2D/Spine/Skeleton Lit`, as a universal 2D Renderer variant of the `Spine/Skeleton Lit` shader, and
      - `Universal Render Pipeline/2D/Spine/Sprite`, as a universal 2D Renderer variant of the `Spine/Sprite/Vertex Lit` and `Pixel Lit` shaders.
        The shaders can be assigned to materials as usual and will respect your settings of the assigned `UniversalRenderPipelineAsset` under `Project Settings - Graphics`.
    - **Restrictions** As all Spine shaders, the URP shaders **do not support `Premultiply alpha` (PMA) atlas textures in Linear color space**. Please export your atlas textures as `straight alpha` textures with disabled `Premultiply alpha` setting when using Linear color space. You can check the current color space via `Project Settings - Player - Other Settings - Color Space.`.
    - **Example:** You can find an example scene in the package under `com.esotericsoftware.spine.urp-shaders-3.8/Examples/URP Shaders.unity` that demonstrates usage of the URP shaders.

  - Spine Preferences now provide an **`Atlas Texture Settings`** parameter for applying customizable texture import settings at all newly imported Spine atlas textures.
    When exporting atlas textures from Spine with `Premultiply alpha` enabled (the default), you can leave it at `PMATexturePreset`. If you have disabled `Premultiply alpha`, set it to the included `StraightAlphaTexturePreset` asset. You can also create your own `TextureImporter` `Preset` asset and assign it here (include `PMA` or `Straight` in the name). In Unity versions before 2018.3 you can use `Texture2D` template assets instead of the newer `Preset` assets. Materials created for imported textures will also have the `Straight Alpha Texture` parameter configured accordingly.
  - All `Sprite` shaders (including URP and LWRP extension packages) now provide an additional `Fixed Normal Space` option `World-Space`. PReviously options were limited to `View-Space` and `Model-Space`.
  - `SkeletonGraphic` now fully supports [`SkeletonUtility`](https://esotericsoftware.com/spine-unity-utility-components#SkeletonUtility) for generating a hierarchy of [`SkeletonUtilityBones`](https://esotericsoftware.com/spine-unity-utility-components#SkeletonUtilityBone) in both modes `Follow` and `Override`. This also enables creating hinge chain physics rigs and using `SkeletonUtilityConstraints` such as `SkeletonUtilityGroundConstraint` and `SkeletonUtilityEyeConstraint` on `SkeletonGraphic`.
  - Added `OnMeshAndMaterialsUpdated` callback event to `SkeletonRenderer` and `SkeletonGraphic`. It is issued at the end of `LateUpdate`, before rendering.
  - Added `Skeleton-OutlineOnly` single pass shader to LWRP and URP extension modules. It can be assigned to materials as `Universal Render Pipeline/Spine/Outline/Skeleton-OutlineOnly`. This allows for separate outline child _GameObjects_ that reference the existing Mesh of their parent, and re-draw the mesh using this outline shader.
  - Added example component `RenderExistingMesh` to render a mesh again with different materials, as required by the new `Skeleton-OutlineOnly` shaders.
    In URP the outline has to be rendered via a separate GameObject as URP does not allow multiple render passes. To add an outline to your SkeletenRenderer:
    1. Add a child GameObject and move it a bit back (e.g. position Z = 0.01).
    2. Add a `RenderExistingMesh` component, provided in the `Spine Examples/Scripts/Sample Components` directory.
    3. Copy the original material, add _\_Outline_ to its name and set the shader to `Universal Render Pipeline/Spine/Outline/Skeleton-OutlineOnly`.
    4. Assign this _\_Outline_ material at the `RenderExistingMesh` component under _Replacement Materials_.
  - Added `Outline Shaders URP` example scene to URP extension module to demonstrate the above additions.
  - Added support for Unity's [`SpriteAtlas`](https://docs.unity3d.com/Manual/class-SpriteAtlas.html) as atlas provider (as an alternative to `.atlas.txt` and `.png` files) alongside a skeleton data file. There is now an additional `Spine SpriteAtlas Import` tool window accessible via `Window - Spine - SpriteAtlas Import`. Additional information can be found in a new section on the [spine-unity documentation page](http://esotericsoftware.com/spine-unity#Advanced---Using-Unity-SpriteAtlas-as-Atlas-Provider).
  - Added support for **multiple atlas textures at `SkeletonGraphic`**. You can enable this feature by enabling the parameter `Multiple CanvasRenders` in the `Advanced` section of the `SkeletonGraphic` Inspector. This automatically creates the required number of child `CanvasRenderer` GameObjects for each required draw call (submesh).
  - Added support for **Render Separator Slots** at `SkeletonGraphic`. Render separation can be enabled directly in the `Advanced` section of the `SkeletonGraphic` Inspector, it does not require any additional components (like `SkeletonRenderSeparator` or `SkeletonPartsRenderer` for `SkeletonRenderer` components). When enabled, additional separator GameObjects will be created automatically for each separation part, and `CanvasRenderer` GameObjects re-parented to them accordingly. The separator GameObjects can be moved around and re-parented in the hierarchy according to your requirements to achieve the desired draw order within your `Canvas`. A usage example can be found in the updated `Spine Examples/Other Examples/SkeletonRenderSeparator` scene.
  - Added `SkeletonGraphicCustomMaterials` component, providing functionality to override materials and textures of a `SkeletonGraphic`, similar to `SkeletonRendererCustomMaterials`. Note: overriding materials or textures per slot is not provided due to structural limitations.
  - Added **Root Motion support** for `SkeletonAnimation`, `SkeletonMecanim` and `SkeletonGraphic` via new components `SkeletonRootMotion` and `SkeletonMecanimRootMotion`. The `SkeletonAnimation` and `SkeletonGraphic` component Inspector now provides a line `Root Motion` with `Add Component` and `Remove Component` buttons to add/remove the new `SkeletonRootMotion` component to your GameObject. The `SkeletonMecanim` Inspector detects whether root motion is enabled at the `Animator` component and adds a `SkeletonMecanimRootMotion` component automatically.
  - `SkeletonMecanim` now provides an additional `Custom MixMode` parameter under `Mecanim Translator`. It is enabled by default in version 3.8 to maintain current behaviour, using the set `Mix Mode` for each Mecanim layer. When disabled, `SkeletonMecanim` will use the recommended `MixMode` according to the layer blend mode. Additional information can be found in the [Mecanim Translator section](http://esotericsoftware.com/spine-unity#Parameters-for-animation-blending-control) on the spine-unity documentation pages.
  - Added **SkeletonGraphic Timeline support**. Added supprot for multi-track Timeline preview in the Editor outside of play mode (multi-track scrubbing). See the [Timeline-Extension-UPM-Package](http://esotericsoftware.com/spine-unity#Timeline-Extension-UPM-Package) section of the spine-unity documentation for more information.
  - Added support for double-sided lighting at all `SkeletonLit` shaders (including URP and LWRP packages).
  - Added frustum culling update mode parameters `Update When Invisible` (Inspector parameter) and `UpdateMode` (available via code) to all Skeleton components. This provides a simple way to disable certain updates when the `Renderer` is no longer visible (outside all cameras, culled in frustum culling). The new `UpdateMode` property allows disabling updates at a finer granularity level than disabling the whole component. Available modes are: `Nothing`, `OnlyAnimationStatus`, `EverythingExceptMesh` and `FullUpdate`.
  - Added a new `Spine/Outline/OutlineOnly-ZWrite` shader to provide correct outline-only rendering. Note: the shader requires two render passes and is therefore not compatible with URP. The `Spine Examples/Other Examples/Outline Shaders` example scene has been updated to demonstrate the new shader.
  - Added `OnMeshAndMaterialsUpdated` callback event to `SkeletonRenderSeparator` and `SkeletonPartsRenderer`. It is issued at the end of `LateUpdate`, before rendering.
  - Added `Root Motion Scale X/Y` parameters to `SkeletonRootMotionBase` subclasses (`SkeletonRootMotion` and `SkeletonMecanimRootMotion`). Also providing `AdjustRootMotionToDistance()` and other methods to allow for easy delta compensation. Delta compensation can be used to e.g. stretch a jump to a given distance. Root motion can be adjusted at the start of an animation or every frame via `skeletonRootMotion.AdjustRootMotionToDistance(targetPosition - transform.position, trackIndex);`.
  - Now providing a `Canvas Group Tint Black` parameter at the `SkeletonGraphic` Inspector in the `Advanced` section. When using the `Spine/SkeletonGraphic Tint Black` shader you can enable this parameter to receive proper blending results when using `Additive` blend mode under a `CanvasGroup`. Be sure to also have the parameter `CanvasGroup Compatible` enabled at the shader. Note that the normal `Spine/SkeletonGraphic` does not support `Additive` blend mode at a `CanvasGroup`, as it requires additional shader channels to work.
  - Added `Mix and Match Skins` example scene to demonstrate how the 3.8 Skin API and combining skins can be used for a wardrobe and equipment use case.
  - Spine Timeline Extensions: Added `Hold Previous` parameter at `SpineAnimationStateClip`.
  - Added more warning messages at incompatible SkeletonRenderer/SkeletonGraphic Component vs Material settings. They appear both as an info box in the Inspector as well as upon initialization in the Console log window. The Inspector box warnings can be disabled via `Edit - Preferences - Spine`.
  - Now providing `BeforeApply` update callbacks at all skeleton animation components (`SkeletonAnimation`, `SkeletonMecanim` and `SkeletonGraphic`).
  - Added `BoundingBoxFollowerGraphic` component. This class is a counterpart of `BoundingBoxFollower` that can be used with `SkeletonGraphic`.
  - Added Inspector context menu functions `SkeletonRenderer - Add all BoundingBoxFollower GameObjects` and `SkeletonGraphic - Add all BoundingBoxFollowerGraphic GameObjects` that automatically generate bounding box follower GameObjects for every `BoundingBoxAttachment` for all skins of a skeleton.
  - `GetRemappedClone()` now provides an additional parameter `pivotShiftsMeshUVCoords` for `MeshAttachment` to prevent uv shifts at a non-central Sprite pivot. This parameter defaults to `true` to maintain previous behaviour.
  - `SkeletonRenderer` components now provide an additional update mode `Only Event Timelines` at the `Update When Invisible` property. This mode saves additional timeline updates compared to update mode `Everything Except Mesh`.
  - Now all URP (Universal Render Pipeline) and LWRP (Lightweight Render Pipeline) shaders support SRP (Scriptable Render Pipeline) batching. See [Unity SRPBatcher documentation pages](https://docs.unity3d.com/Manual/SRPBatcher.html) for additional information.
  - Sprite shaders now provide four `Diffuse Ramp` modes as an Inspector Material parameter: `Hard`, `Soft`, `Old Hard` and `Old Soft`. In spine-unity 3.8 it defaults to `Old Hard` to keep the behaviour of existing projects unchanged. From 4.0 on it defaults to `Hard` for newly created materials while existing ones remain unchanged. Note that `Old Hard` and `Old Soft` ramp versions were using only the right half of the ramp texture, and additionally multiplying the light intensity by 2, both leading to brighter lighting than without a ramp texture active. The new ramp modes `Hard` and `Soft` use the full ramp texture and do not modify light intensity, being consistent with lighting without a ramp texture active.
  - Added **native support for slot blend modes** `Additive`, `Multiply` and `Screen` with automatic assignment at newly imported skeleton assets. `BlendModeMaterialAssets` are now obsolete and replaced by the native properties at `SkeletonDataAsset`. The `SkeletonDataAsset` Inspector provides a new `Blend Modes - Upgrade` button to upgrade an obsolete `BlendModeMaterialAsset` to the native blend modes properties. This upgrade will be performed automatically on imported and re-imported assets in Unity 2020.1 and newer to prevent reported `BlendModeMaterialAsset` issues in these Unity versions. spine-unity 4.0 and newer will automatically perform this upgrade regardless of the Unity version.
  - `BoneFollower` and `BoneFollowerGraphic` components now provide better support for following bones when the skeleton's Transform is not the parent of the follower's Transform. Previously e.g. rotating a common parent Transform did not lead to the desired result, as well as negatively scaling a skeleton's Transform when it is not a parent of the follower's Transform.
  - URP and LWRP `Sprite` and `SkeletonLit` shaders no longer require `Advanced - Add Normals` enabled to properly cast and receive shadows. It is recommended to disable `Add Normals` if normals are otherwise not needed.
  - Added an example component `RootMotionDeltaCompensation` located in `Spine Examples/Scripts/Sample Components` which can be used for applying simple delta compensation. You can enable and disable the component to toggle delta compensation of the currently playing animation on and off.
  - Root motion delta compensation now allows to only adjust X or Y components instead of both. Adds two parameters to `SkeletonRootMotionBase.AdjustRootMotionToDistance()` which default to adjusting both X and Y as before. The `RootMotionDeltaCompensation` example component exposes these parameters as public attributes.
  - Root motion delta compensation now allows to also add translation root motion to e.g. adjust a horizontal jump upwards or downwards over time. This is necessary because a Y root motion of zero cannot be scaled to become non-zero.
  - `Attachment.GetRemappedClone(Sprite)` method now provides an additional optional parameter `useOriginalRegionScale`. When set to `true`, the replaced attachment's scale is used instead of the Sprite's `Pixel per Unity` setting, allowing for more consistent scaling. _Note:_ When remapping Sprites, be sure to set the Sprite's `Mesh Type` to `Full Rect` and not `Tight`, otherwise the scale will be wrong.

- **Changes of default values**

  - `SkeletonMecanim`'s `Layer Mix Mode` now defaults to `MixMode.MixNext` instead of `MixMode.MixAlways`.
  - `BlendModeMaterialAsset` and it's instance `Default BlendModeMaterials.asset` now have `Apply Additive Material` set to `true` by default in order to apply all blend modes by default.

- **Deprecated**

  - Deprecated `Modules/SlotBlendModes/SlotBlendModes` component. Changed namespace from `Spine.Unity.Modules` to `Spine.Unity.Deprecated`. Moved to `Deprecated/SlotBlendModes`.

- **Restructuring (Non-Breaking)**

  Note: The following changes will most likely not affect users of the Spine-Unity runtime as the API remains unchanged and no references are invalidated.

  - Removed duplicates of `.cginc` files in `Modules/Shaders/Sprite` that were also present in the `Modules/Shaders/Sprite/CGIncludes` directory.
  - Moved shaders from `Modules/Shaders` to `Shaders` directory.
  - Moved shaders from `Modules/SkeletonGraphic/Shaders` to `Shaders/SkeletonGraphic`.
  - Renamed shader `Shaders/Spine-SkeletonLit.shader` to `Shaders/Spine-Skeleton-Lit.shader`.
  - Moved components from `SkeletonGraphic` to `Components` and `Components/Following` except for `SkeletonGraphicMirror` which was moved to `Spine Examples/Scripts/Sample Components`.
  - Moved `BoneFollower`, `BoneFollowerGraphic` and `PointFollower` from `Components` directory to `Components/Following`.
  - Moved `BoundingBoxFollower` component from `Modules/BoundingBoxFollower` to `Components/Following`.
  - Moved `Modules/SkeletonRenderSeparator` directory to `Components/SkeletonRenderSeparator`.
  - Moved `Modules/CustomMaterials` directory to `Components/SkeletonRendererCustomMaterials`.
  - Moved `Asset Types/BlendModeMaterialsAsset.cs` class, `Shaders/BlendModes/Default BlendModeMaterials.asset` and materials from `Shaders/BlendModes` to `SkeletonDataModifierAssets/BlendModeMaterials` directory.
  - Moved `Modules/Ghost` directory to `Spine Examples/Scripts/Sample Components/Ghost`.
  - Moved `Modules/SkeletonUtility Modules` directory to `Spine Examples/Scripts/Sample Components/SkeletonUtility Modules`.
  - Moved `Modules/AnimationMatchModifier` directory to `Spine Examples/Scripts/MecanimAnimationMatchModifier`.
  - Moved `SkeletonRagdoll` and `SkeletonRagdoll2D` components from `Modules/Ragdoll` directory to `Spine Examples/Scripts/Sample Components/SkeletonUtility Modules`.
  - Moved `AttachmentTools.cs` to `Utility` directory.
  - Split the file `AttachmentTools` into 5 separate files for each contained class. No namespace or other API changes performed.
  - Split the file `Mesh Generation/SpineMesh` into 4 separate files for each contained class. No namespace or other API changes performed.
  - Moved `SkeletonExtensions.cs` to `Utility` directory.
  - Moved `Modules/YieldInstructions` directory to `Utility/YieldInstructions`.
  - Moved corresponding editor scripts of the above components to restructured directories as well.
  - Renamed inspector editor class `PointFollowerEditor` to `PointFollowerInspector` for consistency reasons.

### XNA/MonoGame

- Updated to latest MonoGame version 3.7.1
- Rewrote example project to be cleaner and better demonstrate basic Spine features.
- Added mix-and-match example to demonstrate the new Skin API.
- Added normalmap support via `SpineEffectNormalmap` and support for loading multiple texture layers following a suffix-pattern. Please see the example code on how to use them.

## Java

- **Breaking changes**

  - Renamed `Slot#getAttachmentVertices()` to `Slot#getDeform()`.
  - Changed the `.json` curve format and added more assumptions for omitted values, reducing the average size of JSON exports.
  - Renamed `Skin#addAttachment()` to `Skin#setAttachment()`.
  - Removed `VertexAttachment#applyDeform()` and replaced it with `VertexAttachment#deformAttachment`. The attachment set on this field is used to decide if a `DeformTimeline` should be applied to the attachment active on the slot to which the timeline is applied.
  - Removed `inheritDeform` field, getter, and setter from `MeshAttachment`.
  - Changed `.skel` binary format, added a string table. References to strings in the data resolve to this string table, reducing storage size of binary files considerably.
  - `JsonRollback` tool now converts from 3.8 JSON to 3.7.
  - Changed the `.json` and `.skel` file formats to accomodate the new feature and file size optimiations. Old projects must be exported with Spine 3.8.20+ to be compatible with the 3.8 Spine runtimes.

- **Additions**
  - Added `x` and `y` coordinates for setup pose AABB in `SkeletonData`.
  - Added support for rotated mesh region UVs.
  - Added skin-specific bones and constraints which are only updated if the skeleton's current skin contains them.
  - Improved Skin API to make it easier to handle mix-and-match use cases.
    - Added `Skin#getAttachments()`. Returns all attachments in the skin.
    - Added `Skin#getAttachments(int slotIndex)`. Returns all attachements in the skin for the given slot index.
    - Added `Skin#addSkin(Skin skin)`. Adds all attachments, bones, and skins from the specified skin to this skin.
    - Added `Skin#copySkin(Skin skin)`. Adds all attachments, bones, and skins from the specified skin to this skin. `VertexAttachment` are shallowly copied and will retain any parent mesh relationship. All other attachment types are deep copied.
  - Added `Attachment#copy()` to all attachment type implementations. This lets you deep copy an attachment to modify it independently from the original, i.e. when programmatically changing texture coordinates or mesh vertices.
  - Added `MeshAttachment#newLinkedMesh()`, creates a linked mesh linkted to either the original mesh, or the parent of the original mesh.
  - Added IK softness.

### libGDX

- `SkeletonViewer` can load a skeleton by specifying it as the first argument on the command line.
- Added mix-and-match example to demonstrate the new Skin API.

## Lua

- **Breaking changes**

  - Renamed `Slot:getAttachmentVertices()` to `Slot#deform`.
  - Changed the `.json` curve format and added more assumptions for omitted values, reducing the average size of JSON exports.
  - Renamed `Skin:addAttachment()` to `Skin#setAttachment()`.
  - Removed `VertexAttachment:applyDeform()` and replaced it with `VertexAttachment#deformAttachment`. The attachment set on this field is used to decide if a `DeformTimeline` should be applied to the attachment active on the slot to which the timeline is applied.
  - Removed `inheritDeform` field, getter, and setter from `MeshAttachment`.
  - Changed the `.json` file format to accomodate the new feature and file size optimiations. Old projects must be exported with Spine 3.8.20+ to be compatible with the 3.8 Spine runtimes.

- **Additions**
  - Added `x` and `y` coordinates for setup pose AABB in `SkeletonData`.
  - Added support for rotated mesh region UVs.
  - Added skin-specific bones and constraints which are only updated if the skeleton's current skin contains them.
  - Improved Skin API to make it easier to handle mix-and-match use cases.
    - Added `Skin:getAttachments()`. Returns all attachments in the skin.
    - Added `Skin:getAttachments(slotIndex)`. Returns all attachements in the skin for the given slot index.
    - Added `Skin:addSkin(Skin skin)`. Adds all attachments, bones, and skins from the specified skin to this skin.
    - Added `Skin:copySkin(Skin skin)`. Adds all attachments, bones, and skins from the specified skin to this skin. `VertexAttachment` are shallowly copied and will retain any parent mesh relationship. All other attachment types are deep copied.
  - Added `Attachment:copy()` to all attachment type implementations. This lets you deep copy an attachment to modify it independently from the original, i.e. when programmatically changing texture coordinates or mesh vertices.
  - Added `MeshAttachment:newLinkedMesh()`, creates a linked mesh linkted to either the original mesh, or the parent of the original mesh.
  - Added IK softness.

### Love2D

- Added support for 0-1 RGBA color component range change in Löve 0.11+. Older Löve versions using the 0-255 range are still supported!
- Added mix-and-match example to demonstrate the new Skin API.

### Corona

- Added mix-and-match example to demonstrate the new Skin API.

## Typescript/Javascript

- **Breaking changes**

  - Renamed `MixDirection.in/out` to `MixDirection.mixIn/mixOut` as it was crashing a JS compressor.
  - Renamed `Slot#getAttachmentVertices()` to `Slot#getDeform()`.
  - Changed the `.json` curve format and added more assumptions for omitted values, reducing the average size of JSON exports.
  - Renamed `Skin#addAttachment()` to `Skin#setAttachment()`.
  - Removed `VertexAttachment#applyDeform()` and replaced it with `VertexAttachment#deformAttachment`. The attachment set on this field is used to decide if a `DeformTimeline` should be applied to the attachment active on the slot to which the timeline is applied.
  - Removed `inheritDeform` field, getter, and setter from `MeshAttachment`.
  - Changed `.skel` binary format, added a string table. References to strings in the data resolve to this string table, reducing storage size of binary files considerably.
  - Changed the `.json` and `.skel` file formats to accomodate the new feature and file size optimiations. Old projects must be exported with Spine 3.8.20+ to be compatible with the 3.8 Spine runtimes.
  - Updated runtime to be compatible with TypeScript 3.6.3.

- **Additions**
  - Added support for loading binary data via `AssetManager#loadBinary()`. `AssetManager#get()` will return a `Uint8Array` for such assets.
  - Added support for loading binaries via new `SkeletonBinary`. Parses a `Uint8Array`.
  - Added `x` and `y` coordinates for setup pose AABB in `SkeletonData`.
  - Added support for rotated mesh region UVs.
  - Added skin-specific bones and constraints which are only updated if the skeleton's current skin contains them.
  - Improved Skin API to make it easier to handle mix-and-match use cases.
    - Added `Skin#getAttachments()`. Returns all attachments in the skin.
    - Added `Skin#getAttachments(slotIndex: number)`. Returns all attachements in the skin for the given slot index.
    - Added `Skin#addSkin(skin: Skin)`. Adds all attachments, bones, and skins from the specified skin to this skin.
    - Added `Skin#copySkin(skin: Skin)`. Adds all attachments, bones, and skins from the specified skin to this skin. `VertexAttachment` are shallowly copied and will retain any parent mesh relationship. All other attachment types are deep copied.
  - Added `Attachment#copy()` to all attachment type implementations. This lets you deep copy an attachment to modify it independently from the original, i.e. when programmatically changing texture coordinates or mesh vertices.
  - Added `MeshAttachment#newLinkedMesh()`, creates a linked mesh linkted to either the original mesh, or the parent of the original mesh.
  - Added IK softness.
  - Added `AssetManager.setRawDataURI(path, data)`. Allows to embed data URIs for skeletons, atlases and atlas page images directly in the HTML/JS without needing to load it from a separate file.
  - Added `AssetManager.loadAll()` to allow Promise/async/await based waiting for completion of asset load. See the `spine-canvas` examples.
  - Added `Skeleton.getBoundRect()` helper method to calculate the bouding rectangle of the current pose, returning the result as `{ x, y, width, height }`. Note that this method will create temporary objects which can add to garbage collection pressure.

### WebGL backend

- `Input` can now take a partially defined implementation of `InputListener`.
- Added mix-and-match example to demonstrate the new Skin API.

### Canvas backend

### Three.js backend

- `SkeletonMesh` now takes an optional `SkeletonMeshMaterialParametersCustomizer` function that allows you to modify the `ShaderMaterialParameters` before the material is finalized. Use it to modify things like THREEJS' `Material.depthTest` etc. See #1590.

### Player

- `SpinePlayer#setAnimation()` can now be called directly to set the animation being displayed.
- The player supports loading `.skel` binary skeleton files by setting the `SpinePlayerConfig#skelUrl` field instead of `SpinePlayerConfig#jsonUrl`.
- Added `SpinePlayerConfig#rawDataURIs`. Allows to embed data URIs for skeletons, atlases and atlas page images directly in the HTML/JS without needing to load it from a separate file. See the example for a demonstration.

# 3.7

## AS3

- **Breaking changes**
  - The completion event will fire for looped 0 duration animations every frame.
  - `MixPose` is now called `MixBlend`
  - Skeleton `flipX/flipY` has been replaced with `scaleX/scaleY`. This cleans up applying transforms and is more powerful. Allows scaling a whole skeleton which has bones that disallow scale inheritance
  - Mix time is no longer affected by `TrackEntry#timeScale`. See https://github.com/EsotericSoftware/spine-runtimes/issues/1194
- **Additions**
  - Added additive animation blending. When playing back multiple animations on different tracks, where each animation modifies the same skeleton property, the results of tracks with lower indices are discarded, and only the result from the track with the highest index is used. With animation blending, the results of all tracks are mixed together. This allows effects like mixing multiple facial expressions (angry, happy, sad) with percentage mixes. By default the old behaviour is retained (results from lower tracks are discarded). To enable additive blending across animation tracks, call `TrackEntry#setMixBlend(MixBlend.add)` on each track. To specify the blend percentage, set `TrackEntry#alpha`. See http://esotericsoftware.com/forum/morph-target-track-animation-mix-mode-9459 for a discussion.
  - Support for stretchy IK
  - Support for audio events, see `audioPath`, `volume` and `balance` fields on event (data).
  - `TrackEntry` has an additional field called `holdPrevious`. It can be used to counter act a limitation of `AnimationState` resulting in "dipping" of parts of the animation. For a full discussion of the problem and the solution we've implemented, see this [forum thread](http://esotericsoftware.com/forum/Probably-Easy-Animation-mixing-with-multiple-tracks-10682?p=48130&hilit=holdprevious#p48130).

### Starling

- Added support for vertex effects. See `RaptorExample.as`
- Added 'getTexture()' method to 'StarlingTextureAtlasAttachmentLoader'
- Breaking change: if a skeleton requires two color tinting, you have to enable it via `SkeletonSprite.twoColorTint = true`. In this case the skeleton will use the `TwoColorMeshStyle`, which internally uses a different vertex layout and shader. This means that skeletons with two color tinting enabled will break batching and hence increase the number of draw calls in your app.
- Added `VertexEffect` and implementations `JitterEffect` and `SwirlEffect`. Allows you to modify vertices before they are submitted for drawing. See Starling changes.
- Fix issues with StarlingAtlasAttachmentLoader, see https://github.com/EsotericSoftware/spine-runtimes/issues/939
- Fix issues with region trimming support, see https://github.com/EsotericSoftware/spine-runtimes/commit/262bc26c64d4111002d80e201cb1a3345e6727df
- Added support for overriding `StarlingAtlasAttachmentLoader#getTexture()`, see https://github.com/EsotericSoftware/spine-runtimes/commit/ea7dbecb98edc74e439aa9ef90dcf6eed865f718
- Texture atlas operations are no longer handled in `Starling#newRegionAttachment` and `Starling#newMeshAttachment` but delegated to the atlas.
- Added sample for additive animation blending, see https://github.com/EsotericSoftware/spine-runtimes/blob/6a556de01429878df47bb276a97959a8bdbbe32f/spine-starling/spine-starling-example/src/spine/examples/OwlExample.as
- Added sample on how to use bounding box attachment vertices https://github.com/EsotericSoftware/spine-runtimes/commit/e20428b02699226164fa73ba4b12f7d029ae6f4d
- Fully transparent meshes are not submitted for rendering.
- No hit-tests are performed when a skeleton is invisible.

## C

- **Breaking changes**
  - Listeners on `spAnimationState` and `spTrackEntry` will now also be called if a track entry gets disposed as part of disposing an animation state.
  - The completion event will fire for looped 0 duration animations every frame.
  - The spine-cocos2dx and spine-ue4 runtimes are now based on spine-cpp. See below for changes.
  - Skeleton `flipX/flipY` has been replaced with `scaleX/scaleY`. This cleans up applying transforms and is more powerful. Allows scaling a whole skeleton which has bones that disallow scale inheritance
  - Mix time is no longer affected by `TrackEntry#timeScale`. See https://github.com/EsotericSoftware/spine-runtimes/issues/1194
  - `spMeshAttachment` has two new fields `regionTextureWith` and `regionTextureHeight`. These must be set in custom attachment loader. See `AtlasAttachmentLoader`.
- **Additions**
  - Added support for local and relative transform constraint calculation, including additional fields in `spTransformConstraintData`.
  - `Animation#apply` and ` Timeline#apply`` now take enums  `MixPose`and`MixDirection` instead of booleans
  - Added `spVertexEffect` and corresponding implementations `spJitterVertexEffect` and `spSwirlVertexEffect`. Create/dispose through the corresponding `spXXXVertexEffect_create()/dispose()` functions. Set on framework/engine specific renderer.
  - Functions in `extension.h` are not prefixed with `_sp` instead of just `_` to avoid interference with other libraries.
  - Introduced `SP_API` macro. Every spine-c function is prefixed with this macro. By default, it is an empty string. Can be used to markup spine-c functions with e.g. ``__declspec` when compiling to a dll or linking to that dll.
  - Added `void *userData` to `spAnimationState`to be consumed in callbacks.
  - Added additive animation blending. When playing back multiple animations on different tracks, where each animation modifies the same skeleton property, the results of tracks with lower indices are discarded, and only the result from the track with the highest index is used. With animation blending, the results of all tracks are mixed together. This allows effects like mixing multiple facial expressions (angry, happy, sad) with percentage mixes. By default the old behaviour is retained (results from lower tracks are discarded). To enable additive blending across animation tracks, call `spTrackEntry->mixBlend = SP_MIXBLEND_ADD)` on each track. To specify the blend percentage, set `spTrackEntry->alpha`. See http://esotericsoftware.com/forum/morph-target-track-animation-mix-mode-9459 for a discussion.
  - Optimized attachment lookup to give a 40x speed-up. See https://github.com/EsotericSoftware/spine-runtimes/commit/cab81276263890b65d07fa2329ace16db1e365ff
  - Support for stretchy IK
  - Support for audio events, see `audioPath`, `volume` and `balance` fields on event (data).
  - `spTrackEntry` has an additional field called `holdPrevious`. It can be used to counter act a limitation of `AnimationState` resulting in "dipping" of parts of the animation. For a full discussion of the problem and the solution we've implemented, see this [forum thread](http://esotericsoftware.com/forum/Probably-Easy-Animation-mixing-with-multiple-tracks-10682?p=48130&hilit=holdprevious#p48130).

### Cocos2d-Objc

- Added vertex effect support to modify vertices of skeletons on the CPU. See `RaptorExample.m`.
- Explanation how to handle ARC, see https://github.com/EsotericSoftware/spine-runtimes/commit/a4f122b08c5e2a51d6aad6fc5a947f7ec31f2eb8
- The super class `::update()` method of `SkeletonRenderer` is now called, see https://github.com/EsotericSoftware/spine-runtimes/commit/f7bb98185236a6d8f35bfefc70afe4f31e9ec9d2
- Added improved tint-black shader.

### SFML

- `spine-sfml.h` no longer defines `SPINE_SHORT_NAMES` to avoid collisions with other APIs. See #1058.
- Added support for vertex effects. See raptor example.
- Added premultiplied alpha support to `SkeletonDrawable`. Use `SkeletonDrawable::setUsePremultipliedAlpha()`, see https://github.com/EsotericSoftware/spine-runtimes/commit/34086c1f41415309b2ecce86055f6656fcba2950
- Added additive animation blending sample, see https://github.com/EsotericSoftware/spine-runtimes/blob/b7e712d3ca1d6be3ebcfe3254dc2cea9c44dda71/spine-sfml/example/main.cpp#L369

## C++

- ** Additions **
  - Added C++ Spine runtime. See the [spine-cpp Runtime Guide](https://esotericsoftware.com/spine-cpp) for more information on spine-cpp.
  - Added parsing of non-essential data (fps, images path, audio path) to for `.json`/`.skel` parsers.

### Cocos2d-x

- Added ETC1 alpha support, thanks @halx99! Does not work when two color tint is enabled.
- Added `spAtlasPage_setCustomTextureLoader()` which let's you do texture loading manually. Thanks @jareguo.
- Added `SkeletonRenderer:setSlotsRange()` and `SkeletonRenderer::createWithSkeleton()`. This allows you to split rendering of a skeleton up into multiple parts, and render other nodes in between. See `SkeletonRendererSeparatorExample.cpp` for an example.
- Fully transparent attachments will not be rendered, improving rendering performance.
- Added improved tint-black shader.
- Updated to cocos2d-x 3.16
- The skeleton setup pose and world transform are now calculated on initialization to avoid flickering on start-up.
- Updated to cocos2d-x 3.17.1
- **Breaking change**: Switched from [spine-c](spine-c) to [spine-cpp](spine-cpp) as the underlying Spine runtime. See the [spine-cpp Runtime Guide](https://esotericsoftware.com/spine-cpp) for more information on spine-cpp.
  - Added `Cocos2dAttachmentLoader` to be used when constructing an `Atlas`. Used by default by `SkeletonAnimation` and `SkeletonRenderer` when creating instances via the `createXXX` methods.
  - All C structs and enums `spXXX` have been replaced with their C++ equivalents `spine::XXX` in all public interfaces.
  - All instantiations via `new` of C++ classes from spine-cpp should contain `(__FILE__, __LINE__)`. This allows the tracking of instantations and detection of memory leaks via the `spine::DebugExtension`.

### SFML

- Create a second SFML backend using [spine-cpp](spine-cpp/). See the [spine-cpp Runtime Guide](https://esotericsoftware.com/spine-cpp) for more information on spine-cpp.
- Added support for vertex effects. See raptor example.
- Added premultiplied alpha support to `SkeletonDrawable`. Use `SkeletonDrawable::setUsePremultipliedAlpha()`, see https://github.com/EsotericSoftware/spine-runtimes/commit/34086c1f41415309b2ecce86055f6656fcba2950
- Added additive animation blending sample, see https://github.com/EsotericSoftware/spine-runtimes/blob/b7e712d3ca1d6be3ebcfe3254dc2cea9c44dda71/spine-sfml/example/main.cpp#L369

### UE4

- spine-c is now exposed from the plugin shared library on Windows via \_\_declspec.
- Updated to Unreal Engine 4.18
- Added C++ example, see https://github.com/EsotericSoftware/spine-runtimes/commit/15011e81b7061495dba45e28b4d3f4efb10d7f40
- `SkeletonRendererComponent` generates collision meshes by default.
- Disabled generation of collision meshes by `SkeletonRendererComponent`. Both `ProceduralMeshComponent` and `RuntimeMeshComponent` have a bug that generates a new PhysiX file every frame per component. Users are advised to add a separate collision shape to the root scene component of an actor instead.
- Using UE4 `FMemory` allocator by default. This should fix issues on some consoles.
- **Breaking change** moved away from `RuntimeMeshComponent`, as its maintainance has seized, back to `ProceduralMeshComponent`. Existing projects should just work. However, if you run into issues, you may have to remove the old `SpineSkeletonRendererComponent` and add a new one to your existing actors.
- **Breaking change** due to the removal of `RuntimeMeshComponent` and reversal to `ProceduralMeshComponent`, two color tinting is currently not supported. `ProceduralMeshComponent` does not support enough vertex attributes for us to encode the second color in the vertex stream. You can remove the `RuntimeMeshComponent/` directory from your plugins directory and remove the component from any `build.cs` files that may reference it.
- **Breaking change**: Switched from [spine-c](spine-c) to [spine-cpp](spine-cpp) as the underlying Spine runtime. See the [spine-cpp Runtime Guide](https://esotericsoftware.com/spine-cpp) for more information on spine-cpp.
- All C structs and enums `spXXX` have been replaced with their C++ equivalents `spine::XXX` in all public interfaces.
- All instantiations via `new` of C++ classes from spine-cpp should contain `(__FILE__, __LINE__)`. This allows the tracking of instantations and detection of memory leaks via the `spine::DebugExtension`.
- Updated to Unreal Engine 4.20 (samples require 4.17+), see the `spine-ue4/Plugins/SpinePlugin/Source/SpinePlugin/SpinePlugin.build.cs` file on how to compile in 4.20 with the latest UBT API changes.
- Updated to Unreal Engine 4.21 (samples require 4.21).
- **Breaking change**: `UBoneDriverComponent` and `UBoneFollowerComponent` are now `USceneComponent` instead of `UActorComponent`. They either update only themselves, or also the owning `UActor`, depending on whether the new flag `UseComponentTransform` is set. See https://github.com/EsotericSoftware/spine-runtimes/pull/1175
- Added query methods for slots, bones, skins and animations to `SpineSkeletonComponent` and `UTrackEntry`. These allow you to query these objects by name in both C++ and blueprints.
- Added `Preview Animation` and `Preview Skin` properties to `SpineSkeletonAnimationComponent`. Enter an animation or skin name to live-preview it in the editor. Enter an empty string to reset the animation or skin.

## C#

- **Breaking changes**
  - The completion event will fire for looped 0 duration animations every frame.
  - Skeleton `flipX/flipY` has been replaced with `scaleX/scaleY`. This cleans up applying transforms and is more powerful. Allows scaling a whole skeleton which has bones that disallow scale inheritance
  - Mix time is no longer affected by `TrackEntry#timeScale`. See https://github.com/EsotericSoftware/spine-runtimes/issues/1194
- **Additions**
  - Added additive animation blending. When playing back multiple animations on different tracks, where each animation modifies the same skeleton property, the results of tracks with lower indices are discarded, and only the result from the track with the highest index is used. With animation blending, the results of all tracks are mixed together. This allows effects like mixing multiple facial expressions (angry, happy, sad) with percentage mixes. By default the old behaviour is retained (results from lower tracks are discarded). To enable additive blending across animation tracks, call `TrackEntry#MixBlend = MixBlend.add` on each track. To specify the blend percentage, set `TrackEntry#Alpha`. See http://esotericsoftware.com/forum/morph-target-track-animation-mix-mode-9459 for a discussion.
  - Support for stretchy IK
  - Support for audio events, see `audioPath`, `volume` and `balance` fields on event (data).
  - `TrackEntry` has an additional field called `holdPrevious`. It can be used to counter act a limitation of `AnimationState` resulting in "dipping" of parts of the animation. For a full discussion of the problem and the solution we've implemented, see this [forum thread](http://esotericsoftware.com/forum/Probably-Easy-Animation-mixing-with-multiple-tracks-10682?p=48130&hilit=holdprevious#p48130).

### Unity

- **Runtime and Editor, and Assembly Definition** Files and folders have been reorganized into "Runtime" and "Editor". Each of these have an `.asmdef` file that defines these separately as their own assembly in Unity _(Note: Spine `.asmdef` files are currently deactivated to `.txt` extension, see below)_. For projects not using assembly definition, you may delete the `.asmdef` files. These assembly definitions will be ignored by older versions of Unity that don't support it.
  - In this scheme, the entirety of the base spine-csharp runtime is inside the "Runtime" folder, to be compiled in the same assembly as spine-unity so they can continue to share internal members.
- **Spine `.asmdef` files are now deactivated (using `.txt` extension) by default** This prevents problems when updating Spine through unitypackages, overwriting the Timeline reference entry in `spine-unity.asmdef` (added automatically when enabling Unity 2019 Timeline support, see `Timeline Support for Unity 2019`), causing compile errors. In case you want to enable the `.asmdef` files, rename the files:
  `Spine/Runtime/spine-unity.txt` to `Spine/Runtime/spine-unity.asmdef` and
  `Spine/Editor/spine-unity-editor.txt` to `Spine/Editor/spine-unity-editor.asmdef`.
- **SkeletonAnimator is now SkeletonMecanim** The Spine-Unity Mecanim-driven component `SkeletonAnimator` has been renamed `SkeletonMecanim` to make it more autocomplete-friendly and more obvious at human-glance. The .meta files and guids should remain intact so existing projects and prefabs should not break. However, user code needs to be updated to use `SkeletonMecanim`.
- **SpineAtlasAsset** The existing `AtlasAsset` type has been renamed to `SpineAtlasAsset` to signify that it specifically uses a Spine/libGDX atlas as its source. Serialization should be intact but user code will need to be updated to refer to existing atlases as `SpineAtlasAsset`.
  - **AtlasAssetBase** `SpineAtlasAsset` now has an abstract base class called `SpineAtlasAsset`. This is the base class to derive when using alternate atlas sources. Existing SkeletonDataAsset field "atlasAssets" now have the "AtlasAssetBase" type. Serialization should be intact, but user code will need to be updated to refer to the atlas assets accordingly.
  - This change is in preparation for alternate atlas options such as Unity's SpriteAtlas.
- **Optional Straight Alpha for shaders** Spine-Unity's included Unity shaders now have a `_STRAIGHT_ALPHA_INPUT` shader_feature, toggled as a checkbox in the Material's inspector. This allows the Material to use a non-premultiplied alpha/straight alpha input texture.
  - The following shaders now have the "Straight Alpha Texture" checkbox when used on a material:
    - `Spine/Skeleton`
    - `Spine/Skeleton Tint Black`
    - `Spine/Skeleton Lit`
    - `Spine/Skeleton Tint`
    - `Spine/Skeleton Fill`
    - `Spine/SkeletonGraphic (Premultiply Alpha)` was renamed to `Spine/SkeletonGraphic`
    - `Spine/SkeletonGraphic Tint Black (Premultiply Alpha)` was renamed to `Spine/SkeletonGraphic Tint Black`
    - `Spine/Skeleton PMA Multiply`
    - `Spine/Skeleton PMA Screen`
  - Dedicated straight alpha shaders were removed from the runtime.
    - `Spine/Straight Alpha/Skeleton Fill`
    - `Spine/Straight Alpha/Skeleton Tint`
- **Detection of Incorrect Texture Settings** Especially when atlas textures are exported with setting `Premultiply alpha` enabled, it is important to configure Unity's texture import settings correctly. By default, you will now receive warnings where texture settings are expected to cause incorrect rendering.
  - The following rules apply:
    - `sRGB (Color Texture)` shall be disabled when `Generate Mip Maps` is enabled, otherwise you will receive white border outlines.
    - `Alpha Is Transparency` shall be disabled on `Premultiply alpha` textures, otherwise you will receive light ghosting artifacts in transparent areas.
  - These warnings can be disabled in `Edit - Preferences - Spine`.
- **Sprite Mask Support for all Included Shaders** The `Skeleton Animation` and `Skeleton Mecanim` components now provide an additional `Mask Interaction` field in the Inspector, covering identical functionality as Unity's built in `Sprite Renderer` component:
  - `Mask Interaction` modes:
    - `None` - The sprite will not interact with the masking system. Default behavior.
    - `Visible Inside Mask` - The sprite will be visible only in areas where a mask is present.
    - `Visible Outside Mask` - The sprite will be visible only in areas where no mask is present.
  - `Automatically Generated Materials` When switching `Mask Interaction` modes in the Inspector outside of Play mode, the required additional material assets are generated for the respective `Stencil Compare` parameters - with file suffixes `'_InsideMask'` and `'_OutsideMask'`, placed in the same folder as the original materials. By default all generated materials are kept as references by the `Skeleton Animation` component for switching at runtime.
    These materials can be managed and optimized via the `SkeletonAnimation`'s `Advanced` section:
    - Using the `Clear` button you can clear the reference to unneeded materials,
    - Using the `Delete` button the respective assets are deleted as well as references cleared. Note that other `Skeleton Animation` GameObjects might still reference the materials, so use with caution!
    - With the `Set` button you can again assign a link to the respective materials to prepare them for runtime use. If the materials were not present or have been deleted, they are generated again based on the default materials.
  - When switching `Mask Interaction` mode at runtime, the previously prepared materials are switched active automatically. When the respective materials have not been prepared, material copies of the default materials are created on the fly. Note that these materials are not shared between similar `Skeleton Animation` GameObjects, so it is recommended to use the generated material assets where possible.
  - **Every shader now exposes the `Stencil Compare` parameter** for further customization. This way you have maximum flexibility to use custom mechanisms to switch materials at runtime if you should ever need more than the three materials generated by `Skeleton Animation`'s `Mask Interaction` parameter. Reference `Stencil Compare` values are:
    - `CompareFunction.Disabled` for `Mask Interaction - None`
    - `CompareFunction.LessEqual` for `Mask Interaction - Visible Inside Mask`
    - `CompareFunction.Greater` for `Mask Interaction - Visible Outside Mask`
- **RectMask2D Support for SkeletonGraphic** Both `SkeletonGraphic` shaders '`Spine/SkeletonGraphic`' and '`Spine/SkeletonGraphic Tint Black`' now respect masking areas defined via Unity's `RectMask2D` component.
- **Timeline Support for Unity 2019** using the existing Timeline components. By default, all Spine Timeline components are deactivated in Unity 2019 and **can be activated via the Spine Preferences menu**. This step became necessary because in Unity 2019, Timeline has been moved to a separate Package and is no longer included in the Unity core. Please visit `Edit - Preferences - Spine` and at `Timeline Package Support` hit `Enable` to automatically perform all necessary steps to activate the Timeline components.
  This will automatically:
  1. download the Unity Timeline package
  2. activate the Spine Timeline components by setting the compile definition `SPINE_TIMELINE_PACKAGE_DOWNLOADED` for all platforms
  3. modify the `spine-unity.asmdef` file by adding the reference to the Unity Timeline library.
- Added `Create 2D Hinge Chain` functionality at `SkeletonUtilityBone` inspector, previously only `Create 3D Hinge Chain` was available.

### XNA/MonoGame

- Added support for any `Effect` to be used by `SkeletonRenderer`
- Added support for `IVertexEffect` to modify vertices of skeletons on the CPU. `IVertexEffect` instances can be set on the `SkeletonRenderer`. See example project.
- Added `SkeletonDebugRenderer`
- Made `MeshBatcher` of SkeletonRenderer accessible via a getter. Allows user to batch their own geometry together with skeleton meshes for maximum batching instead of using XNA SpriteBatcher.

## Java

- **Breaking changes**
  - Skeleton attachments: Moved update of attached skeleton out of libGDX `SkeletonRenderer`, added overloaded method `Skeleton#updateWorldTransform(Bone)`, used for `SkeletonAttachment`. You now MUST call this new method with the bone of the parent skeleton to which the child skeleton is attached. See `SkeletonAttachmentTest` for and example.
  - The completion event will fire for looped 0 duration animations every frame.
  - `MixPose` is now called `MixBlend`.
  - Skeleton `flipX/flipY` has been replaced with `scaleX/scaleY`. This cleans up applying transforms and is more powerful. Allows scaling a whole skeleton which has bones that disallow scale inheritance
  - Mix time is no longer affected by `TrackEntry#timeScale`. See https://github.com/EsotericSoftware/spine-runtimes/issues/1194
- **Additions**
  - Added `EventData#audioPath` field. This field contains the file name of the audio file used for the event.
  - Added convenience method to add all attachments from one skin to another, see https://github.com/EsotericSoftware/spine-runtimes/commit/a0b7bb6c445efdfac12b0cdee2057afa3eff3ead
  - Added additive animation blending. When playing back multiple animations on different tracks, where each animation modifies the same skeleton property, the results of tracks with lower indices are discarded, and only the result from the track with the highest index is used. With animation blending, the results of all tracks are mixed together. This allows effects like mixing multiple facial expressions (angry, happy, sad) with percentage mixes. By default the old behaviour is retained (results from lower tracks are discarded). To enable additive blending across animation tracks, call `TrackEntry#setMixBlend(MixBlend.add)` on each track. To specify the blend percentage, set `TrackEntry#alpha`. See http://esotericsoftware.com/forum/morph-target-track-animation-mix-mode-9459 for a discussion.
  - Support for stretchy IK
  - Support for audio events, see `audioPath`, `volume` and `balance` fields on event (data).
  - `TrackEntry` has an additional field called `holdPrevious`. It can be used to counter act a limitation of `AnimationState` resulting in "dipping" of parts of the animation. For a full discussion of the problem and the solution we've implemented, see this [forum thread](http://esotericsoftware.com/forum/Probably-Easy-Animation-mixing-with-multiple-tracks-10682?p=48130&hilit=holdprevious#p48130).

### libGDX

- Added `VertexEffect` interface, instances of which can be set on `SkeletonRenderer`. Allows to modify vertices before submitting them to GPU. See `SwirlEffect`, `JitterEffect` and `VertexEffectTest`.
- Added improved tint-black shader.
- Improved performance by avoiding batch flush when not switching between normal and additive rendering with PMA
- Improvements to skeleton viewer.
- `TwoColorPolygonBatch` implements the `Batch` interface, allowing to the be used with other libGDX classes that require a batcher for drawing, potentially improving performance. See https://github.com/EsotericSoftware/spine-runtimes/commit/a46b3d1d0c135d51f9bef9ca17a5f8e5dda69927
- Added `SkeletonDrawable` to render skeletons in scene2d UI https://github.com/EsotericSoftware/spine-runtimes/commit/b93686c185e2c9d5466969a8e07eee573ebe4b97

## Lua

- **Breaking changes**
  - The completion event will fire for looped 0 duration animations every frame.
  - Skeleton `flipX/flipY` has been replaced with `scaleX/scaleY`. This cleans up applying transforms and is more powerful. Allows scaling a whole skeleton which has bones that disallow scale inheritance
  - Mix time is no longer affected by `TrackEntry#timeScale`. See https://github.com/EsotericSoftware/spine-runtimes/issues/1194
- **Additions**
  - Added `JitterEffect` and `SwirlEffect` and support for vertex effects in Corona and Love
  - Added additive animation blending. When playing back multiple animations on different tracks, where each animation modifies the same skeleton property, the results of tracks with lower indices are discarded, and only the result from the track with the highest index is used. With animation blending, the results of all tracks are mixed together. This allows effects like mixing multiple facial expressions (angry, happy, sad) with percentage mixes. By default the old behaviour is retained (results from lower tracks are discarded). To enable additive blending across animation tracks, call `TrackEntry:setMixBlend(MixBlend.add)` on each track. To specify the blend percentage, set `TrackEntry.alpha`. See http://esotericsoftware.com/forum/morph-target-track-animation-mix-mode-9459 for a discussion.
  - Support for stretchy IK
  - Support for audio events, see `audioPath`, `volume` and `balance` fields on event (data).
  - `TrackEntry` has an additional field called `holdPrevious`. It can be used to counter act a limitation of `AnimationState` resulting in "dipping" of parts of the animation. For a full discussion of the problem and the solution we've implemented, see this [forum thread](http://esotericsoftware.com/forum/Probably-Easy-Animation-mixing-with-multiple-tracks-10682?p=48130&hilit=holdprevious#p48130).

### Love2D

- Added support for vertex effects. Set an implementation like "JitterEffect" on `Skeleton.vertexEffect`. See `main.lua` for an example.

### Corona

- Added support for vertex effects. Set an implementation like "JitterEffect" on `SkeletonRenderer.vertexEffect`. See `main.lua` for an example

## Typescript/Javascript

- **Breaking changes**
  - The completion event will fire for looped 0 duration animations every frame.
  - Skeleton `flipX/flipY` has been replaced with `scaleX/scaleY`. This cleans up applying transforms and is more powerful. Allows scaling a whole skeleton which has bones that disallow scale inheritance
  - Mix time is no longer affected by `TrackEntry#timeScale`. See https://github.com/EsotericSoftware/spine-runtimes/issues/1194
- **Additions**
  - Added `AssetManager.loadTextureAtlas`. Instead of loading the `.atlas` and corresponding image files manually, you can simply specify the location of the `.atlas` file and AssetManager will load the atlas and all its images automatically. `AssetManager.get("atlasname.atlas")` will then return an instance of `spine.TextureAtlas`.
  - Added additive animation blending. When playing back multiple animations on different tracks, where each animation modifies the same skeleton property, the results of tracks with lower indices are discarded, and only the result from the track with the highest index is used. With animation blending, the results of all tracks are mixed together. This allows effects like mixing multiple facial expressions (angry, happy, sad) with percentage mixes. By default the old behaviour is retained (results from lower tracks are discarded). To enable additive blending across animation tracks, call `TrackEntry#setMixBlend(MixBlend.add)` on each track. To specify the blend percentage, set `TrackEntry#alpha`. See http://esotericsoftware.com/forum/morph-target-track-animation-mix-mode-9459 for a discussion. See https://github.com/EsotericSoftware/spine-runtimes/blob/f045d221836fa56191ccda73dd42ae884d4731b8/spine-ts/webgl/tests/test-additive-animation-blending.html for an example.
  - Added work-around for iOS WebKit JIT bug, see https://github.com/EsotericSoftware/spine-runtimes/commit/c28bbebf804980f55cdd773fed9ff145e0e7e76c
  - Support for stretchy IK
  - Support for audio events, see `audioPath`, `volume` and `balance` fields on event (data).
  - `TrackEntry` has an additional field called `holdPrevious`. It can be used to counter act a limitation of `AnimationState` resulting in "dipping" of parts of the animation. For a full discussion of the problem and the solution we've implemented, see this [forum thread](http://esotericsoftware.com/forum/Probably-Easy-Animation-mixing-with-multiple-tracks-10682?p=48130&hilit=holdprevious#p48130).
  - Added `AssetManager#setRawDataURI(path, data)`. Allows to set raw data URIs for a specific path, which in turn enables embedding assets into JavaScript/HTML.
  - `PolygonBatcher` will now disable `CULL_FACE` and restore the state as it was before rendering.

### WebGL backend

- Added `VertexEffect` interface, instances of which can be set on `SkeletonRenderer`. Allows to modify vertices before submitting them to GPU. See `SwirlEffect`, `JitterEffect`, and the example which allows to set effects.
- Added `slotRangeStart` and `slotRangeEnd` parameters to `SkeletonRenderer#draw` and `SceneRenderer#drawSkeleton`. This allows you to render only a range of slots in the draw order. See `spine-ts/webgl/tests/test-slot-range.html` for an example.
- Added improved tint-black shader.
- Added `SceneRenderer#drawTextureUV()`, allowing to draw a texture with manually specified texture coordinates.
- Exposed all renderers in `SceneRenderer`.

### Canvas backend

- Added support for shearing and non-uniform scaling inherited from parent bones.
- Added support for alpha tinting.

### Three.js backend

- Added `VertexEffect` interface, instances of which can be set on `SkeletonMesh`. Allows to modify vertices before submitting them to GPU. See `SwirlEffect`, `JitterEffect`.
- Added support for multi-page atlases

### Widget backend

- Added fields `atlasContent`, `atlasPagesContent`, and `jsonContent` to `WidgetConfiguration` allowing you to directly pass the contents of the `.atlas`, atlas page `.png` files, and the `.json` file without having to do a request. See `README.md` and the example for details.
- `SpineWidget.setAnimation()` now takes an additional optional parameter for callbacks when animations are completed/interrupted/etc.

# 3.6

## AS3

- **Breaking changes**

  - Removed `Bone.worldToLocalRotationX` and `Bone.worldToLocalRotationY`. Replaced by `Bone.worldToLocalRotation` (rotation given relative to x-axis, counter-clockwise, in degrees).
  - Made `Bone` fields `_a`, `_b`, `_c`, `_d`, `_worldX` and `_worldY` public, removed underscore prefix.
  - Removed `VertexAttachment.computeWorldVertices` overload, changed `VertexAttachment.computeWorldVertices2` to `VertexAttachment.computeWorldVertices`, added `stride` parameter.
  - Removed `RegionAttachment.vertices` field. The vertices array is provided to `RegionAttachment.computeWorldVertices` by the API user now.
  - Removed `RegionAttachment.updateWorldVertices`, added `RegionAttachment.computeWorldVertices`. The new method now computes the x/y positions of the 4 vertices of the corner and places them in the provided `worldVertices` array, starting at `offset`, then moving by `stride` array elements when advancing to the next vertex. This allows to directly compose the vertex buffer and avoids a copy. The computation of the full vertices, including vertex colors and texture coordinates, is now done by the backend's respective renderer.
  - Replaced `r`, `g`, `b`, `a` fields with instances of new `Color` class in `RegionAttachment`, `MeshAttachment`, `Skeleton`, `SkeletonData`, `Slot` and `SlotData`.
  - The completion event will fire for looped 0 duration animations every frame.

- **Additions**
  - Added `Skeleton.getBounds` from reference implementation.
  - Added support for local and relative transform constraint calculation, including additional fields in `TransformConstraintData`
  - Added `Bone.localToWorldRotation`(rotation given relative to x-axis, counter-clockwise, in degrees).
  - Added two color tinting support, including `TwoColorTimeline` and additional fields on `Slot` and `SlotData`.
  - Added `PointAttachment`, additional method `newPointAttachment` in `AttachmentLoader` interface.
  - Added `ClippingAttachment`, additional method `newClippingAttachment` in `AttachmentLoader` interface.
  - `AnimationState#apply` returns boolean indicating if any timeline was applied or not.
  - `Animation#apply` and ` Timeline#apply`` now take enums  `MixPose`and`MixDirection` instead of booleans
  - Added `VertexEffect` and implementations `JitterEffect` and `SwirlEffect`. Allows you to modify vertices before they are submitted for drawing. See Starling changes.

### Starling

- Fixed renderer to work with 3.6 changes.
- Added support for two color tinting.
- Added support for clipping.
- Added support for rotated regions in texture atlas loaded via StarlingAtlasAttachmentLoader.
- Added support for vertex effects. See `RaptorExample.as`
- Added 'getTexture()' method to 'StarlingTextureAtlasAttachmentLoader'
- Breaking change: if a skeleton requires two color tinting, you have to enable it via `SkeletonSprite.twoColorTint = true`. In this case the skeleton will use the `TwoColorMeshStyle`, which internally uses a different vertex layout and shader. This means that skeletons with two color tinting enabled will break batching and hence increase the number of draw calls in your app.

## C

- **Breaking changes**
  - `spVertexAttachment_computeWorldVertices` and `spRegionAttachment_computeWorldVerticeS` now take new parameters to make it possible to directly output the calculated vertex positions to a vertex buffer. Removes the need for additional copies in the backends' respective renderers.
  - Removed `spBoundingBoxAttachment_computeWorldVertices`, superseded by `spVertexAttachment_computeWorldVertices`.
  - Removed `spPathAttachment_computeWorldVertices` and `spPathAttachment_computeWorldVertices1`, superseded by `spVertexAttachment_computeWorldVertices`.
  - Removed `sp_MeshAttachment_computeWorldVertices`, superseded by `spVertexAttachment_computeWorldVertices`.
  - Removed `spBone_worldToLocalRotationX` and `spBone_worldToLocalRotationY`. Replaced by `spBone_worldToLocalRotation` (rotation given relative to x-axis, counter-clockwise, in degrees).
  - Replaced `r`, `g`, `b`, `a` fields with instances of new `spColor` struct in `spRegionAttachment`, `spMeshAttachment`, `spSkeleton`, `spSkeletonData`, `spSlot` and `spSlotData`.
  - Removed `spVertexIndex`from public API.
  - Listeners on `spAnimationState` or `spTrackEntry` will now be also called in case a track entry is disposed as part of dispoing the `spAnimationState`.
  - The completion event will fire for looped 0 duration animations every frame.
- **Additions**
  - Added support for local and relative transform constraint calculation, including additional fields in `spTransformConstraintData`.
  - Added `spPointAttachment`, additional method `spAtlasAttachmentLoadeR_newPointAttachment`.
  - Added support for local and relative transform constraint calculation, including additional fields in `TransformConstraintData`
  - Added `spBone_localToWorldRotation`(rotation given relative to x-axis, counter-clockwise, in degrees).
  - Added two color tinting support, including `spTwoColorTimeline` and additional fields on `spSlot` and `spSlotData`.
  - Added `userData` field to `spTrackEntry`, so users can expose data in `spAnimationState` callbacks.
  - Modified kvec.h used by SkeletonBinary.c to use Spine's MALLOC/FREE macros. That way there's only one place to inject custom allocators ([extension.h](https://github.com/EsotericSoftware/spine-runtimes/blob/master/spine-c/spine-c/include/spine/extension.h)) [commit](https://github.com/EsotericSoftware/spine-runtimes/commit/c2cfbc6cb8709daa082726222d558188d75a004f)
  - Added macros to define typed dynamic arrays, see `Array.h/.c`
  - Added `spClippingAttachment` and respective enum.
  - Added `spSkeletonClipper` and `spTriangulator`, used to implement software clipping of attachments.
  - `AnimationState#apply` returns boolean indicating if any timeline was applied or not.
  - `Animation#apply` and ` Timeline#apply`` now take enums  `MixPose`and`MixDirection` instead of booleans
  - Added `spVertexEffect` and corresponding implementations `spJitterVertexEffect` and `spSwirlVertexEffect`. Create/dispose through the corresponding `spXXXVertexEffect_create()/dispose()` functions. Set on framework/engine specific renderer. See changes for spine-c based frameworks/engines below.
  - Functions in `extension.h` are not prefixed with `_sp` instead of just `_` to avoid interference with other libraries.
  - Introduced `SP_API` macro. Every spine-c function is prefixed with this macro. By default, it is an empty string. Can be used to markup spine-c functions with e.g. ``__declspec` when compiling to a dll or linking to that dll.

### Cocos2d-X

- Fixed renderer to work with 3.6 changes
- Optimized rendering by removing all per-frame allocation in `SkeletonRenderer`, resulting in 15% performance increase for large numbers of skeletons being rendered per frame.
- Added support for two color tinting. Tinting is enabled/disabled per `SkeletonRenderer`/`SkeletonAnimation` instance. Use `SkeletonRenderer::setTwoColorTint()`. Note that two color tinting requires the use of a non-standard shader and vertex format. This means that skeletons rendered with two color tinting will break batching. However, skeletons with two color tinting enabled and rendered after each other will be batched.
- Updated example to use Cocos2d-x 3.14.1.
- Added mesh debug rendering. Enable/Disable via `SkeletonRenderer::setDebugMeshesEnabled()`.
- Added support for clipping.
- SkeletonRenderer now combines the displayed color of the Node (cascaded from all parents) with the skeleton color for tinting.
- Added support for vertex effects. See `RaptorExample.cpp`.
- Added ETC1 alpha support, thanks @halx99! Does not work when two color tint is enabled.
- Added `spAtlasPage_setCustomTextureLoader()` which let's you do texture loading manually. Thanks @jareguo.
- Added `SkeletonRenderer:setSlotsRange()` and `SkeletonRenderer::createWithSkeleton()`. This allows you to split rendering of a skeleton up into multiple parts, and render other nodes in between. See `SkeletonRendererSeparatorExample.cpp` for an example.

### Cocos2d-Objc

- Fixed renderer to work with 3.6 changes
- Added support for two color tinting. Tinting is enabled/disabled per `SkeletonRenderer/SkeletonAnimation.twoColorTint = true`. Note that two color tinted skeletons do not batch with other nodes.
- Added support for clipping.

### SFML

- Fixed renderer to work with 3.6 changes. Sadly, two color tinting does not work, as the vertex format in SFML is fixed.
- Added support for clipping.
- Added support for vertex effects. See raptor example.
- Added premultiplied alpha support to `SkeletonDrawable`.

### Unreal Engine 4

- Fixed renderer to work with 3.6 changes
- Added new UPROPERTY to SpineSkeletonRendererComponent called `Color`. This allows to set the tint color of the skeleton in the editor, C++ and Blueprints. Under the hood, the `spSkeleton->color` will be set on every tick of the renderer component.
- Added support for clipping.
- Switched from built-in ProceduralMeshComponent to RuntimeMeshComponent by Koderz (https://github.com/Koderz/UE4RuntimeMeshComponent, MIT). Needed for more flexibility regarding vertex format, should not have an impact on existing code/assets. You need to copy the RuntimeMeshComponentPlugin from our repository in `spine-ue4\Plugins\` to your project as well!
- Added support for two color tinting. All base materials, e.g. SpineUnlitNormalMaterial, now do proper two color tinting. No material parameters have changed.
- Updated to Unreal Engine 4.16.1. Note that 4.16 has a regression which will make it impossible to compile plain .c files!
- spine-c is now exposed from the plugin shared library on Windows via \_\_declspec.

## C#

- **Breaking changes**

  - `MeshAttachment.parentMesh` is now a private field to enforce using the `.ParentMesh` setter property in external code. The `MeshAttachment.ParentMesh` property is an appropriate replacement wherever `.parentMesh` was used.
  - `Skeleton.GetBounds` takes a scratch array as input so it doesn't have to allocate a new array on each invocation itself. Reduces GC activity.
  - Removed `Bone.WorldToLocalRotationX` and `Bone.WorldToLocalRotationY`. Replaced by `Bone.WorldToLocalRotation` (rotation given relative to x-axis, counter-clockwise, in degrees).
  - Added `stride` parameter to `VertexAttachment.ComputeWorldVertices`.
  - Removed `RegionAttachment.Vertices` field. The vertices array is provided to `RegionAttachment.ComputeWorldVertices` by the API user now.
  - Removed `RegionAttachment.UpdateWorldVertices`, added `RegionAttachment.ComputeWorldVertices`. The new method now computes the x/y positions of the 4 vertices of the corner and places them in the provided `worldVertices` array, starting at `offset`, then moving by `stride` array elements when advancing to the next vertex. This allows to directly compose the vertex buffer and avoids a copy. The computation of the full vertices, including vertex colors and texture coordinates, is now done by the backend's respective renderer.
  - The completion event will fire for looped 0 duration animations every frame.

- **Additions**
- Added support for local and relative transform constraint calculation, including additional fields in `TransformConstraintData`
- Added `Bone.localToWorldRotation`(rotation given relative to x-axis, counter-clockwise, in degrees).
- Added two color tinting support, including `TwoColorTimeline` and additional fields on `Slot` and `SlotData`.
- Added `PointAttachment`, additional method `NewPointAttachment` in `AttachmentLoader` interface.
- Added `ClippingAttachment`, additional method `NewClippingAttachment` in `AttachmentLoader` interface.
- Added `SkeletonClipper` and `Triangulator`, used to implement software clipping of attachments.
- `AnimationState.Apply` returns a bool indicating if any timeline was applied or not.
- `Animation.Apply` and ` Timeline.Apply`` now take enums  `MixPose`and`MixDirection` instead of bools.

### Unity

- Refactored renderer to work with new 3.6 features.
  - **Two color tinting** is currently supported via extra UV2 and UV3 mesh vertex streams. To use Two color tinting, you need to:
    - switch on "Tint Black" under "Advanced...",
    - use the new `Spine/Skeleton Tint Black` shader, or your own shader that treats the UV2 and UV3 streams similarly.
    - Additionally, for SkeletonGraphic, you can use `Spine/SkeletonGraphic Tint Black` (or the bundled SkeletonGraphicTintBlack material) or your own shader that uses UV2 and UV3 streams similarly. **Additional Shader Channels** TexCoord1 and TexCoord2 will need to be enabled from the Canvas component's inspector. These correspond to UV2 and UV3.
  - **Clipping** is now supported. Caution: The SkeletonAnimation switches to slightly slower mesh generation code when clipping so limit your use of `ClippingAttachment`s when using on large numbers of skeletons.
- **SkeletonRenderer.initialFlip** Spine components such as SkeletonRenderer, SkeletonAnimation, SkeletonAnimator now has `initialFlipX` and `initialFlipY` fields which are also visible in the inspector under "Advanced...". It will allow you to set and preview a starting flip value for your skeleton component. This is applied immediately when the internal skeleton object is instantiated.
- **[SpineAttribute] Improvements**
  - **Icons have been added to SpineAttributeDrawers**. This should make your default inspectors easier to understand at a glance.
  - **Added Constraint Attributes** You can now use `[SpineIkConstraint]` `[SpineTransformConstraint]` `[SpinePathConstraint]`
  - **SpineAttribute dataField** parameter can also now detect sibling fields within arrays and serializable structs/classes.
  - **[SpineAttribute(includeNone:false)]** SpineAttributes now have an `includeNone` optional parameter to specify if you want to include or exclude a none ("") value option in the dropdown menu. Default is `includeNone:true`.
  - **[SpineAttachment(skinField:"mySkin")]** The SpineAttachment attribute now has a skinField optional parameter to limit the dropdown items to attachments in a specific skin instead of the just default skin or all the skins in SkeletonData.
- **SkeletonDebugWindow**. Debugging tools have been moved from the SkeletonAnimation and SkeletonUtility component inspectors into its own utility window. You can access "Skeleton Debug" under the `Advanced...` foldout in the SkeletonAnimation inspector, or in SkeletonAnimation's right-click/context menu.
  - **Skeleton Baking Window** The old Skeleton Baking feature is also now accessible through the SkeletonDataAsset's right-click/context menu.
- **AttachmentTools source material**. `AttachmentTools` methods can now accept a `sourceMaterial` argument to copy material properties from.
- **AttachmentTools Skin Extensions**. Using AttachmentTools, you can now add entries by slot name by also providing a skeleton argument. Also `Append(Skin)`, `RemoveAttachment` and `Clear` have been added.
- **BoneFollower and SkeletonUtilityBone Add RigidBody Button**. The BoneFollower and SkeletonUtilityBone component inspectors will now offer to add a `Rigidbody` or `Rigidbody2D` if it detects a collider of the appropriate type. Having a rigidbody on a moving transform with a collider fits better with the Unity physics systems and prevents excess calculations. It will not detect colliders on child objects so you have to add Rigidbody components manually accordingly.
- **SkeletonRenderer.OnPostProcessVertices** is a new callback that gives you a reference to the MeshGenerator after it has generated a mesh from the current skeleton pose. You can access `meshGenerator.VertexBuffer` or `meshGenerator.ColorBuffer` to modify these before they get pushed into the UnityEngine.Mesh for rendering. This can be useful for non-shader vertex effects.
- **Examples**
  - **Examples now use properties**. The code in the example scripts have been switched over to using properties instead of fields to encourage their use for consistency. This is in anticipation of both users who want to move the Spine folders to the Unity Plugins folder (compiled as a different assembly), and of Unity 2017's ability to manually define different assemblies for shorter compilation times.
  - **Mix And Match**. The mix-and-match example scene, code and data have been updated to reflect the current recommended setup for animation-compatible custom equip systems The underlying API has changed since 3.5 and the new API calls in MixAndMatch.cs is recommended. Documentation is in progress.
  - **Sample Components**. `AtasRegionAttacher` and `SpriteAttacher` are now part of `Sample Components`, to reflect that they are meant to be used as sample code rather than production. A few other sample components have also been added. New imports of the unitypackage Examples folder will see a "Legacy" folder comprised of old sample components that no longer contain the most up-to-date and recommended workflows, but are kept in case old setups used them for production.
- **Spine folder**. In the unitypackage, the "spine-csharp" and "spine-unity" folders are now inside a "Spine" folder. This change will only affect fresh imports. Importing the unitypackage to update Spine-Unity in your existing project will update the appropriate files however you chose to arrange them, as long as the meta files are intact.
- **Breaking changes**
  - The Sprite shaders module was updated to the latest version from the [source](https://github.com/traggett/UnitySpriteShaders/commits/master). Some changes were made to the underlying keyword structure. You may need to review the settings of your lit materials. Particularly, your Fixed Normals settings.
  - The `Spine/Skeleton Lit` shader was switched over to non-fixed-function code. It now no longer requires mesh normals and has fixed normals at the shader level.
  - The old MeshGenerator classes, interfaces and code in `Spine.Unity.MeshGeneration` are now deprecated. All mesh-generating components now share the class `Spine.Unity.MeshGenerator` defined in `SpineMesh.cs`. MeshGenerator is a serializable class.
    - The `SkeletonRenderer.renderMeshes` optimization is currently non-functional.
    - Old triangle-winding code has been removed from `SkeletonRenderer`. Please use shaders that have backface culling off.
    - Render settings in `SkeletonGraphic` can now be accessed under `SkeletonGraphic.MeshGenerator.settings`. This is visible in the SkeletonGraphic inspector as `Advanced...`
    - We will continue to bundle the unitypackage with the empty .cs files of deprecated classes until Spine 3.7 to ensure the upgrade process does not break.
  - The [SpineAttachment(slotField:)] optional parameter found property value now acts as a Find(slotName) argument rather than Contains(slotName).
  - `SkeletonAnimator` now uses a `SkeletonAnimator.MecanimTranslator` class to translate an Animator's Mecanim State Machine into skeleton poses. This makes code reuse possible for a Mecanim version of SkeletonGraphic.
  - `SkeletonAnimator` `autoreset` and the `mixModes` array are now a part of SkeletonAnimator's MecanimTranslator `.Translator`. `autoReset` is set to `true` by default. Old prefabs and scene objects with Skeleton Animator may no longer have correct values set.
  - Warnings and conditionals checking for specific Unity 5.2-and-below incompatibility have been removed.

## XNA/MonoGame

- Added support for clipping
- Removed `RegionBatcher` and `SkeletonRegionRenderer`, renamed `SkeletonMeshRenderer` to `SkeletonRenderer`
- Added support for two color tint. For it to work, you need to add the `SpineEffect.fx` file to your content project, then load it via `var effect = Content.Load<Effect>("SpineEffect");`, and set it on the `SkeletonRenderer`. See the example project for code.
- Added support for any `Effect` to be used by `SkeletonRenderer`
- Added support for `IVertexEffect` to modify vertices of skeletons on the CPU. `IVertexEffect` instances can be set on the `SkeletonRenderer`. See example project.
- Added `SkeletonDebugRenderer`
- Made `MeshBatcher` of SkeletonRenderer accessible via a getter. Allows user to batch their own geometry together with skeleton meshes for maximum batching instead of using XNA SpriteBatcher.

## Java

- **Breaking changes**

  - `Skeleton.getBounds` takes a scratch array as input so it doesn't have to allocate a new array on each invocation itself. Reduces GC activity.
  - Removed `Bone.worldToLocalRotationX` and `Bone.worldToLocalRotationY`. Replaced by `Bone.worldToLocalRotation` (rotation given relative to x-axis, counter-clockwise, in degrees).
  - Added `stride` parameter to `VertexAttachment.computeWorldVertices`.
  - Removed `RegionAttachment.vertices` field. The vertices array is provided to `RegionAttachment.computeWorldVertices` by the API user now.
  - Removed `RegionAttachment.updateWorldVertices`, added `RegionAttachment.computeWorldVertices`. The new method now computes the x/y positions of the 4 vertices of the corner and places them in the provided `worldVertices` array, starting at `offset`, then moving by `stride` array elements when advancing to the next vertex. This allows to directly compose the vertex buffer and avoids a copy. The computation of the full vertices, including vertex colors and texture coordinates, is now done by the backend's respective renderer.
  - Skeleton attachments: Moved update of attached skeleton out of libGDX `SkeletonRenderer`, added overloaded method `Skeleton#updateWorldTransform(Bone), used for `SkeletonAttachment`. You now MUST call this new method
with the bone of the parent skeleton to which the child skeleton is attached. See `SkeletonAttachmentTest` for and example.
  - The completion event will fire for looped 0 duration animations every frame.

- **Additions**
  - Added support for local and relative transform constraint calculation, including additional fields in `TransformConstraintData`
  - Added `Bone.localToWorldRotation`(rotation given relative to x-axis, counter-clockwise, in degrees).
  - Added two color tinting support, including `TwoColorTimeline` and additional fields on `Slot` and `SlotData`.
  - Added `PointAttachment`, additional method `newPointAttachment` in `AttachmentLoader` interface.
  - Added `ClippingAttachment`, additional method `newClippingAttachment` in `AttachmentLoader` interface.
  - Added `SkeletonClipper` and `Triangulator`, used to implement software clipping of attachments.
  - `AnimationState#apply` returns boolean indicating if any timeline was applied or not.
  - `Animation#apply` and ` Timeline#apply`` now take enums  `MixPose`and`MixDirection` instead of booleans

### libGDX

- Fixed renderer to work with 3.6 changes
- Added support for two color tinting. Use the new `TwoColorPolygonBatch` together with `SkeletonRenderer`
- Added support for clipping. See `SkeletonClipper`. Used automatically by `SkeletonRenderer`. Does not work when using a `SpriteBatch` with `SkeletonRenderer`. Use `PolygonSpriteBatch` or `TwoColorPolygonBatch` instead.
- Added `VertexEffect` interface, instances of which can be set on `SkeletonRenderer`. Allows to modify vertices before submitting them to GPU. See `SwirlEffect`, `JitterEffect` and `VertexEffectTest`.

## Lua

- **Breaking changes**
  - Removed `Bone:worldToLocalRotationX` and `Bone:worldToLocalRotationY`. Replaced by `Bone:worldToLocalRotation` (rotation given relative to x-axis, counter-clockwise, in degrees).
  - `VertexAttachment:computeWorldVertices` now takes offsets and stride to allow compositing vertices directly in a vertex buffer to be send to the GPU. The compositing is now performed in the backends' respective renderers. This also affects the subclasses `MeshAttachment`, `BoundingBoxAttachment` and `PathAttachment`.
  - Removed `RegionAttachment:updateWorldVertices`, added `RegionAttachment:computeWorldVertices`, which takes offsets and stride to allow compositing vertices directly in a vertex buffer to be send to the GPU. The compositing is now performed in the backends' respective renderers.
  - Removed `MeshAttachment.worldVertices` field. Computation is now performed in each backends' respective renderer. The `uv` coordinates are now stored in `MeshAttachment.uvs`.
  - Removed `RegionAttachment.vertices` field. Computation is now performed in each backends respective renderer. The `uv` coordinates for each vertex are now stored in the `RegionAttachment.uvs` field.
  - The completion event will fire for looped 0 duration animations every frame.
- **Additions**
- Added `Bone:localToWorldRotation`(rotation given relative to x-axis, counter-clockwise, in degrees).
- Added two color tinting support, including `TwoColorTimeline` and additional fields on `Slot` and `SlotData`.
- Added `PointAttachment`, additional method `newPointAttachment` in `AttachmentLoader` interface.
- Added support for local and relative transform constraint calculation, including additional fields in `TransformConstraintData`
- Added `ClippingAttachment`, additional method `newClippingAttachment` in `AttachmentLoader` interface.
- Added `SkeletonClipper` and `Triangulator`, used to implement software clipping of attachments.
- `AnimationState#apply` returns boolean indicating if any timeline was applied or not.
- `Animation#apply` and ` Timeline#apply`` now take enums  `MixPose`and`MixDirection` instead of booleans
- Added `JitterEffect` and `SwirlEffect` and support for vertex effects in Corona and Love

### Love2D

- Fixed renderer to work with 3.6 changes
- Added support for two color tinting. Enable it via `SkeletonRenderer.new(true)`.
- Added clipping support.
- Added support for vertex effects. Set an implementation like "JitterEffect" on `Skeleton.vertexEffect`. See `main.lua` for an example.

### Corona

- Fixed renderer to work with 3.6 changes. Sadly, two color tinting is not supported, as Corona doesn't let us change the vertex format needed and its doesn't allow to modify shaders in the way needed for two color tinting
- Added clipping support.
- Added support for vertex effects. Set an implementation like "JitterEffect" on `SkeletonRenderer.vertexEffect`. See `main.lua` for an example

## Typescript/Javascript

- **Breaking changes**

  - `Skeleton.getBounds` takes a scratch array as input so it doesn't have to allocate a new array on each invocation itself. Reduces GC activity.
  - Removed `Bone.worldToLocalRotationX` and `Bone.worldToLocalRotationY`. Replaced by `Bone.worldToLocalRotation` (rotation given relative to x-axis, counter-clockwise, in degrees).
  - Removed `VertexAttachment.computeWorldVertices` overload, changed `VertexAttachment.computeWorldVerticesWith` to `VertexAttachment.computeWorldVertices`, added `stride` parameter.
  - Removed `RegionAttachment.vertices` field. The vertices array is provided to `RegionAttachment.computeWorldVertices` by the API user now.
  - Removed `RegionAttachment.updateWorldVertices`, added `RegionAttachment.computeWorldVertices`. The new method now computes the x/y positions of the 4 vertices of the corner and places them in the provided `worldVertices` array, starting at `offset`, then moving by `stride` array elements when advancing to the next vertex. This allows to directly compose the vertex buffer and avoids a copy. The computation of the full vertices, including vertex colors and texture coordinates, is now done by the backend's respective renderer.
  - The completion event will fire for looped 0 duration animations every frame.
  - Removed the Spine Widget in favor of [Spine Web Player](https://esotericsoftware.com/spine-player).

- **Additions**
  - Added support for local and relative transform constraint calculation, including additional fields in `TransformConstraintData`
  - Added `Bone.localToWorldRotation`(rotation given relative to x-axis, counter-clockwise, in degrees).
  - Added two color tinting support, including `TwoColorTimeline` and additional fields on `Slot` and `SlotData`.
  - Added `PointAttachment`, additional method `newPointAttachment` in `AttachmentLoader` interface.
  - Added `ClippingAttachment`, additional method `newClippingAttachment` in `AttachmentLoader` interface.
  - Added `SkeletonClipper` and `Triangulator`, used to implement software clipping of attachments.
  - `AnimationState#apply` returns boolean indicating if any timeline was applied or not.
  - `Animation#apply` and ` Timeline#apply`` now take enums  `MixPose`and`MixDirection` instead of booleans
  - Added `AssetManager.loadTextureAtlas`. Instead of loading the `.atlas` and corresponding image files manually, you can simply specify the location of the `.atlas` file and AssetManager will load the atlas and all its images automatically. `AssetManager.get("atlasname.atlas")` will then return an instance of `spine.TextureAtlas`.
  - Added the [Spine Web Player](https://esotericsoftware.com/spine-player)

### WebGL backend

- Fixed WebGL context loss
  - Added `Restorable` interface, implemented by any WebGL resource that needs restoration after a context loss. All WebGL resource classes (`Shader`, `Mesh`, `GLTexture`) implement this interface.
  - Added `ManagedWebGLRenderingContext`. Handles setup of a `WebGLRenderingContext` given a canvas element and restoration of WebGL resources (`Shader`, `Mesh`, `GLTexture`) on WebGL context loss. WebGL resources register themselves with the `ManagedWebGLRenderingContext`. If the context is informed of a context loss and restoration, the registered WebGL resources' `restore()` method is called. The `restore()` method implementation on each resource type will recreate the GPU side objects.
  - All classes that previously took a `WebGLRenderingContext` in the constructor now also allow a `ManagedWebGLRenderingContext`. This ensures existing applications do not break.
  - To use automatic context restauration:
  1. Create or fetch a canvas element from the DOM
  2. Instantiate a `ManagedWebGLRenderingContext`, passing the canvas to the constructor. This will setup a `WebGLRenderingContext` internally and manage context loss/restoration.
  3. Pass the `ManagedWebGLRenderingContext` to the constructors of classes that you previously passed a `WebGLRenderingContext` to (`AssetManager`, `GLTexture`, `Mesh`, `Shader`, `PolygonBatcher`, `SceneRenderer`, `ShapeRenderer`, `SkeletonRenderer`, `SkeletonDebugRenderer`).
- Fixed renderer to work with 3.6 changes.
- Added support for two color tinting.
- Improved performance by using `DYNAMIC_DRAW` for vertex buffer objects and fixing bug that copied to much data to the GPU each frame in `PolygonBatcher`/`Mesh`.
- Added two color tinting support, enabled by default. You can disable it via the constructors of `SceneRenderer`, `SkeletonRenderer`and `PolygonBatcher`. Note that you will need to use a shader created via `Shader.newTwoColoredTexturedShader` shader with `SkeletonRenderer` and `PolygonBatcher` if two color tinting is enabled.
- Added clipping support
- Added `VertexEffect` interface, instances of which can be set on `SkeletonRenderer`. Allows to modify vertices before submitting them to GPU. See `SwirlEffect`, `JitterEffect`, and the example which allows to set effects.
- Added `slotRangeStart` and `slotRangeEnd` parameters to `SkeletonRenderer#draw` and `SceneRenderer#drawSkeleton`. This allows you to render only a range of slots in the draw order. See `spine-ts/webgl/tests/test-slot-range.html` for an example.

### Canvas backend

- Fixed renderer to work for 3.6 changes. Sadly, we can't support two color tinting via the Canvas API.
- Added support for shearing and non-uniform scaling inherited from parent bones.
- Added support for alpha tinting.

### Three.js backend

- Fixed renderer to work with 3.6 changes. Two color tinting is not supported.
- Added clipping support
- Added `VertexEffect` interface, instances of which can be set on `SkeletonMesh`. Allows to modify vertices before submitting them to GPU. See `SwirlEffect`, `JitterEffect`.
- Added support for multi-page atlases

### Widget backend

- Fixed WebGL context loss (see WebGL backend changes). Enabled automatically.
- Fixed renderer to work for 3.6 changes. Supports two color tinting & clipping (see WebGL backend changes for details).
- Added fields `atlasContent`, `atlasPagesContent`, and `jsonContent` to `WidgetConfiguration` allowing you to directly pass the contents of the `.atlas`, atlas page `.png` files, and the `.json` file without having to do a request. See `README.md` and the example for details.
- `SpineWidget.setAnimation()` now takes an additional optional parameter for callbacks when animations are completed/interrupted/etc.