Significant API and behaviour changes to OpenVDB AX in this release. Main
API changes to codegen and AST components. Changes to OpenVDB Volume
execution involving volumes of differing topologies. Active states now
only determine the final application of a value rather than their impact on
other volumes. For example:
@a = 2;
@b = @a;
Irrespective of the overlapping activity, active @b voxels will be set to 2.
Previously, this would only occur if @a was active at the given location,
producing an implicit dependency of the active topology of @a on @b.
New Features:
- Support for for, while and do-while loops using standard c-like syntax.
Includes break and continue keyword handling.
- Attribute, external and local support for 3x3 and 4x4 matrices and 2 and 4
component vectors using the following tokens: mat3f, mat3d, mat4f, mat4d,
vec2i, vec2f, vec2d, vec4i, vec4f, vec4d. Attributes and externals use the
same tokens with @ and $ respectively
- New array style indexing support for vectors and matrices. Both can be
indexed as an array using single [0] operations. Matrices can be indexed
by row, column using [0,0]
- Added non keyword {} scope support
- New functions added: identity3, identity4, postscale, prescale,
pretransform, simplexnoise, transform, transpose, curlsimplexnoise
- Significantly improved the performance of duplicate attribute accesses for
points and volumes
- New compound assignment support for %=, &=, |= and ^=
- Better handling of LHS values within assignment operations, including
support for cremented attributes
- Added pyopenvdbax module which exposes basic python bindings for AX.
Provides compilation of executables and execution on VDB grids through
Python.
- New arguments and modes to the vdb_ax binary. Analysis provides detailed
information for a given ax snippet. More tools to search and list available
functions
- Significantly re-worked volume execution. Each volume now receives the
same singularly generated AX function. This more closely matches Houdini
VEX behaviour
- New reprint() methods for printing an AST as AX code
- New scanner methods and API for returning detailed information from an AST
- Added the ability to iterate over any active state for Volumes
Bug fixes:
- Fixed a crash which could occur when destructing AX executables. This was
due to the destruction order of LLVM objects which have since been
reversed.
- Fixed a bug in SymbolTableBlocks::find which could occur if an out of range
index was used
- Fixed an issue during AX compilation caused by invalid IR when branching
after a return statement
Improvements:
- Function signatures are now printed with their AX types rather than their
LLVM types (i.e. int(short) vs i32(i16))
- Significantly improved the descriptive printing of any parsed AST
- Added lexer location tracking for error line and column numbering
- Significantly improved backend string support
- Introduced new methods for dependency tracking attributes for efficiently
determining the copy requirements of volumes
- Moved testing CMake config into its own CMakeLists.txt.
- Significantly improved the descriptive printing of any parsed AST
- Improved code documentation throughout the library
- Improved doxygen generation
- Improved position access for OpenVDB Points
- Renamed 'lookup' function to 'external'
- Moved function structs to .cc's and added methods to populate function
registries
- Removed the old FunctionContext System from derived function methods
- Removed legacy code supporting multiple return values from
FunctionSignatures
- Added virtual destructors to FunctionBase and FunctionSignature classes
Houdini:
- Fixed an issue where the VDB name was taken over the Houdini Primitive
name for VDBs passed into the OpenVDB AX SOP
- Renamed the OpenVDB AX node type from DN_OpenVDBAX to openvdbax
- Improved the OpenVDB AX SOP UI, added the ability to iterate over
different value states and the ability to post compact point attributes
AST:
- The Visitor and Modifier have been removed in favour of a new Visitor CRTP
- Introduced AST tokens for type inference
- Introduced implicit parent tracking to AST nodes
- Introduced full and short AST node names
- Converted all child AST nodes to unique pointers from shared pointers
- Introduced child indexing and in-place node replacement
- New token to represent types to avoid passing around strings
- Removed VectorPack/Unpack in favour of ArrayPack/Unpack
- Refactored the crement node to only own a single variable
Grammar:
- Significant clean-up and improvements to lexer and parser
- Removed legacy component assignments in favour of new workflows for point
and volume vector attributes in their respective code generators
- mat3f, mat3d, mat4f, mat4d, vec2i, vec2f, vec2d, vec4i, vec4f, vec4d, []
and [,] support
- Improved the operator precedence definitions in the parser
- New variable_reference rule for assignable objects
- Types passed around using new type tokens
- Bison and Flex methods are now all prefixed (with ax) to support multiple
lexers within the same program
- Removed unused tokens in the lexer
- Improved lexer whitespace support
- Added reserved keywords in the lexer
Code Generation:
- Strings are now represented by a custom LLVM struct which holds a
re-allocatable char* and an int64_t for the size
- Getters and setters for new attribute type support
- All literals (except for arrays) are passed around as constants and are no
longer allocated
- String literals are now created as global IR values so that the same
literals can be shared
- Removed VectorPack/Unpack IR generation in favour of ArrayPack/Unpack
- Updated all visitors to use new AST methods
- Point/volume compute generator no longer overrides crement and assign.
Instead, attributes are retrieved once at the beginning of the tree and
set at the end
- Point/volume compute generator create and return their own attribute
registry to infer read/write accesses
- The volume generator now accepts an additional accessor and index
representing the volume being accessed
- The function framework now supports nullptr returns for IR functions which
return void
- Changed the core function storage from void* to void(*)() to adhere to
point-to-function standard
Compiler:
- Completely removed volume blocks. A single function is generated which is
run for every volume
- Volume executable updated to support new volume workflow
CMake / Build / Testing:
- Updated to OpenVDB 6.1 CMake modules
- Added CMake support for grammar generation
- Added CMake options for static/shared library generation
- Updated the CMake test framework to run the snippets directly from the
source repository without copying
- Improved LLVM version support for versions 6/7/8
- Various fixes for clang and MacOS
- Overhaul of frontend tests to compare full AST generation
- Travis improvements including OSX builds
- Travis build matrices for LLVM 5/6/7/8, clang/gcc, osx/linux
