diff options
Diffstat (limited to 'source/slang')
| -rw-r--r-- | source/slang/slang-ir-glsl-legalize.cpp | 31 |
1 files changed, 29 insertions, 2 deletions
diff --git a/source/slang/slang-ir-glsl-legalize.cpp b/source/slang/slang-ir-glsl-legalize.cpp index 263e56f55..2c889f341 100644 --- a/source/slang/slang-ir-glsl-legalize.cpp +++ b/source/slang/slang-ir-glsl-legalize.cpp @@ -414,9 +414,36 @@ GLSLSystemValueInfo* getGLSLSystemValueInfo( { // uint in hlsl, int in glsl // https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/gl_PrimitiveID.xhtml - name = "gl_PrimitiveID"; - requiredType = builder->getBasicType(BaseType::Int); + + switch( context->getStage() ) + { + default: + name = "gl_PrimitiveID"; + break; + + case Stage::Geometry: + // GLSL makes a confusing design choice here. + // + // All the non-GS stages use `gl_PrimitiveID` to access + // the *input* primitive ID, but a GS uses `gl_PrimitiveID` + // to acces an *output* primitive ID (that will be passed + // along to the fragment shader). + // + // For a GS to get an input primitive ID (the thing that + // other stages access with `gl_PrimitiveID`), the + // programmer must write `gl_PrimitiveIDIn`. + // + if( kind == LayoutResourceKind::VaryingInput ) + { + name = "gl_PrimitiveIDIn"; + } + else + { + name = "gl_PrimitiveID"; + } + break; + } } else if (semanticName == "sv_rendertargetarrayindex") { |