Migrate cameras to required components (bevyengine#15641)

# Objective

Yet another PR for migrating stuff to required components. This time,
cameras!

## Solution

As per the [selected
proposal](https://hackmd.io/tsYID4CGRiWxzsgawzxG_g#Combined-Proposal-1-Selected),
deprecate `Camera2dBundle` and `Camera3dBundle` in favor of `Camera2d`
and `Camera3d`.

Adding a `Camera` without `Camera2d` or `Camera3d` now logs a warning,
as suggested by Cart [on
Discord](https://discord.com/channels/691052431525675048/1264881140007702558/1291506402832945273).
I would personally like cameras to work a bit differently and be split
into a few more components, to avoid some footguns and confusing
semantics, but that is more controversial, and shouldn't block this core
migration.

## Testing

I ran a few 2D and 3D examples, and tried cameras with and without
render graphs.

---

## Migration Guide

`Camera2dBundle` and `Camera3dBundle` have been deprecated in favor of
`Camera2d` and `Camera3d`. Inserting them will now also insert the other
components required by them automatically.

Author: Jondolf

Cargo.toml

@@ -346,7 +346,7 @@ android_shared_stdcxx = ["bevy_internal/android_shared_stdcxx"]
 # Enable detailed trace event logging. These trace events are expensive even when off, thus they require compile time opt-in
 detailed_trace = ["bevy_internal/detailed_trace"]
 
-# Include tonemapping Look Up Tables KTX2 files. If everything is pink, you need to enable this feature or change the `Tonemapping` method on your `Camera2dBundle` or `Camera3dBundle`.
+# Include tonemapping Look Up Tables KTX2 files. If everything is pink, you need to enable this feature or change the `Tonemapping` method for your `Camera2d` or `Camera3d`.
 tonemapping_luts = ["bevy_internal/tonemapping_luts", "ktx2", "zstd"]
 
 # Include SMAA Look Up Tables KTX2 Files

crates/bevy_core_pipeline/src/core_2d/camera_2d.rs

@@ -1,3 +1,5 @@
+#![expect(deprecated)]
+
 use crate::{
     core_2d::graph::Core2d,
     tonemapping::{DebandDither, Tonemapping},
@@ -17,12 +19,25 @@ use bevy_render::{
 };
 use bevy_transform::prelude::{GlobalTransform, Transform};
 
+/// A 2D camera component. Enables the 2D render graph for a [`Camera`].
 #[derive(Component, Default, Reflect, Clone, ExtractComponent)]
 #[extract_component_filter(With<Camera>)]
 #[reflect(Component, Default)]
+#[require(
+    Camera,
+    DebandDither,
+    CameraRenderGraph(|| CameraRenderGraph::new(Core2d)),
+    OrthographicProjection(OrthographicProjection::default_2d),
+    Frustum(|| OrthographicProjection::default_2d().compute_frustum(&GlobalTransform::from(Transform::default()))),
+    Tonemapping(|| Tonemapping::None),
+)]
 pub struct Camera2d;
 
 #[derive(Bundle, Clone)]
+#[deprecated(
+    since = "0.15.0",
+    note = "Use the `Camera2d` component instead. Inserting it will now also insert the other components required by it automatically."
+)]
 pub struct Camera2dBundle {
     pub camera: Camera,
     pub camera_render_graph: CameraRenderGraph,

crates/bevy_core_pipeline/src/core_3d/camera_3d.rs

@@ -1,3 +1,5 @@
+#![expect(deprecated)]
+
 use crate::{
     core_3d::graph::Core3d,
     tonemapping::{DebandDither, Tonemapping},
@@ -15,12 +17,22 @@ use bevy_render::{
 use bevy_transform::prelude::{GlobalTransform, Transform};
 use serde::{Deserialize, Serialize};
 
-/// Configuration for the "main 3d render graph".
-/// The camera coordinate space is right-handed x-right, y-up, z-back.
+/// A 3D camera component. Enables the main 3D render graph for a [`Camera`].
+///
+/// The camera coordinate space is right-handed X-right, Y-up, Z-back.
 /// This means "forward" is -Z.
 #[derive(Component, Reflect, Clone, ExtractComponent)]
 #[extract_component_filter(With<Camera>)]
 #[reflect(Component, Default)]
+#[require(
+    Camera,
+    DebandDither(|| DebandDither::Enabled),
+    CameraRenderGraph(|| CameraRenderGraph::new(Core3d)),
+    Projection,
+    Tonemapping,
+    ColorGrading,
+    Exposure
+)]
 pub struct Camera3d {
     /// The depth clear operation to perform for the main 3d pass.
     pub depth_load_op: Camera3dDepthLoadOp,
@@ -139,6 +151,10 @@ pub enum ScreenSpaceTransmissionQuality {
 /// The camera coordinate space is right-handed x-right, y-up, z-back.
 /// This means "forward" is -Z.
 #[derive(Bundle, Clone)]
+#[deprecated(
+    since = "0.15.0",
+    note = "Use the `Camera3d` component instead. Inserting it will now also insert the other components required by it automatically."
+)]
 pub struct Camera3dBundle {
     pub camera: Camera,
     pub camera_render_graph: CameraRenderGraph,

crates/bevy_core_pipeline/src/lib.rs

@@ -45,6 +45,7 @@ pub mod experimental {
 /// The core pipeline prelude.
 ///
 /// This includes the most common types in this crate, re-exported for your convenience.
+#[expect(deprecated)]
 pub mod prelude {
     #[doc(hidden)]
     pub use crate::{

crates/bevy_core_pipeline/src/motion_blur/mod.rs

@@ -59,11 +59,11 @@ pub struct MotionBlurBundle {
 /// camera.
 ///
 /// ```
-/// # use bevy_core_pipeline::{core_3d::Camera3dBundle, motion_blur::MotionBlur};
+/// # use bevy_core_pipeline::{core_3d::Camera3d, motion_blur::MotionBlur};
 /// # use bevy_ecs::prelude::*;
 /// # fn test(mut commands: Commands) {
 /// commands.spawn((
-///     Camera3dBundle::default(),
+///     Camera3d::default(),
 ///     MotionBlur::default(),
 /// ));
 /// # }

crates/bevy_core_pipeline/src/tonemapping/mod.rs

@@ -263,7 +263,7 @@ impl SpecializedRenderPipeline for TonemappingPipeline {
                 error!(
                     "AgX tonemapping requires the `tonemapping_luts` feature.
                     Either enable the `tonemapping_luts` feature for bevy in `Cargo.toml` (recommended),
-                    or use a different `Tonemapping` method in your `Camera2dBundle`/`Camera3dBundle`."
+                    or use a different `Tonemapping` method for your `Camera2d`/`Camera3d`."
                 );
                 shader_defs.push("TONEMAP_METHOD_AGX".into());
             }
@@ -275,7 +275,7 @@ impl SpecializedRenderPipeline for TonemappingPipeline {
                 error!(
                     "TonyMcMapFace tonemapping requires the `tonemapping_luts` feature.
                     Either enable the `tonemapping_luts` feature for bevy in `Cargo.toml` (recommended),
-                    or use a different `Tonemapping` method in your `Camera2dBundle`/`Camera3dBundle`."
+                    or use a different `Tonemapping` method for your `Camera2d`/`Camera3d`."
                 );
                 shader_defs.push("TONEMAP_METHOD_TONY_MC_MAPFACE".into());
             }
@@ -284,7 +284,7 @@ impl SpecializedRenderPipeline for TonemappingPipeline {
                 error!(
                     "BlenderFilmic tonemapping requires the `tonemapping_luts` feature.
                     Either enable the `tonemapping_luts` feature for bevy in `Cargo.toml` (recommended),
-                    or use a different `Tonemapping` method in your `Camera2dBundle`/`Camera3dBundle`."
+                    or use a different `Tonemapping` method for your `Camera2d`/`Camera3d`."
                 );
                 shader_defs.push("TONEMAP_METHOD_BLENDER_FILMIC".into());
             }

crates/bevy_dev_tools/src/ui_debug_overlay/mod.rs

@@ -4,7 +4,7 @@ use core::any::{Any, TypeId};
 use bevy_app::{App, Plugin, PostUpdate};
 use bevy_color::Hsla;
 use bevy_core::Name;
-use bevy_core_pipeline::core_2d::Camera2dBundle;
+use bevy_core_pipeline::core_2d::Camera2d;
 use bevy_ecs::{prelude::*, system::SystemParam};
 use bevy_gizmos::{config::GizmoConfigStore, prelude::Gizmos, AppGizmoBuilder};
 use bevy_hierarchy::{Children, Parent};
@@ -88,17 +88,15 @@ fn update_debug_camera(
     } else {
         let spawn_cam = || {
             cmds.spawn((
-                Camera2dBundle {
-                    projection: OrthographicProjection {
-                        far: 1000.0,
-                        viewport_origin: Vec2::new(0.0, 0.0),
-                        ..OrthographicProjection::default_3d()
-                    },
-                    camera: Camera {
-                        order: LAYOUT_DEBUG_CAMERA_ORDER,
-                        clear_color: ClearColorConfig::None,
-                        ..default()
-                    },
+                Camera2d,
+                OrthographicProjection {
+                    far: 1000.0,
+                    viewport_origin: Vec2::new(0.0, 0.0),
+                    ..OrthographicProjection::default_3d()
+                },
+                Camera {
+                    order: LAYOUT_DEBUG_CAMERA_ORDER,
+                    clear_color: ClearColorConfig::None,
                     ..default()
                 },
                 LAYOUT_DEBUG_LAYERS.clone(),

crates/bevy_ecs/src/bundle.rs

@@ -55,9 +55,6 @@ use core::{any::TypeId, ptr::NonNull};
 /// would create incoherent behavior.
 /// This would be unexpected if bundles were treated as an abstraction boundary, as
 /// the abstraction would be unmaintainable for these cases.
-/// For example, both `Camera3dBundle` and `Camera2dBundle` contain the `CameraRenderGraph`
-/// component, but specifying different render graphs to use.
-/// If the bundles were both added to the same entity, only one of these two bundles would work.
 ///
 /// For this reason, there is intentionally no [`Query`] to match whether an entity
 /// contains the components of a bundle.

crates/bevy_gltf/src/loader.rs

@@ -9,7 +9,7 @@ use bevy_asset::{
 };
 use bevy_color::{Color, LinearRgba};
 use bevy_core::Name;
-use bevy_core_pipeline::prelude::Camera3dBundle;
+use bevy_core_pipeline::prelude::Camera3d;
 use bevy_ecs::{
     entity::{Entity, EntityHashMap},
     world::World,
@@ -1413,15 +1413,15 @@ fn load_node(
                     Projection::Perspective(perspective_projection)
                 }
             };
-            node.insert(Camera3dBundle {
+            node.insert((
+                Camera3d::default(),
                 projection,
                 transform,
-                camera: Camera {
+                Camera {
                     is_active: !*active_camera_found,
                     ..Default::default()
                 },
-                ..Default::default()
-            });
+            ));
 
             *active_camera_found = true;
         }

crates/bevy_pbr/src/fog.rs

@@ -29,10 +29,7 @@ use bevy_render::{extract_component::ExtractComponent, prelude::Camera};
 /// # fn system(mut commands: Commands) {
 /// commands.spawn((
 ///     // Setup your camera as usual
-///     Camera3dBundle {
-///         // ... camera options
-/// #       ..Default::default()
-///     },
+///     Camera3d::default(),
 ///     // Add fog to the same entity
 ///     DistanceFog {
 ///         color: Color::WHITE,