HLSL: better support for geometry shaders builtins#2603
Merged
HansKristian-Work merged 4 commits intoKhronosGroup:mainfrom Feb 26, 2026
Merged
HLSL: better support for geometry shaders builtins#2603HansKristian-Work merged 4 commits intoKhronosGroup:mainfrom
HansKristian-Work merged 4 commits intoKhronosGroup:mainfrom
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HansKristian-Work
approved these changes
Feb 26, 2026
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SV_Position in geometry shaders (1ca6a7a)
Geometry shaders have both an input and output gl_Position, which requires two separate global variables.
A
has_separate_input_outputloop was introduced in emit_builtin_variables() to emit both gl_PositionIn (input, array-sized by vertex count) and gl_Position (output).Note: this also applies to BuiltInSampleMask (which had different type as input and output) and is now handled automatically with the same system.
SV_PrimitiveID / SV_GSInstanceID in geometry shaders (3b374ae)
In HLSL, SV_PrimitiveID is passed as a direct function parameter to the geometry shader entry point rather than via the input struct. The input struct emission is suppressed for GS, the parameter is added to the entry point argument list, and the copy-in assigns gl_PrimitiveIDIn = gl_PrimitiveID. SV_GSInstanceID (mapping to BuiltInInvocationId) is handled similarly for instanced geometry shaders.
Fix per-vertex array dimension stripping (707bc66)
SPIR-V stores array dimensions in reverse order (outermost dimension last in the array vector). The previous code removed the innermost dimension, which was wrong.