diff options
| -rw-r--r-- | source/slang/type-layout.cpp | 41 | ||||
| -rw-r--r-- | tests/reflection/std430-layout.glsl | 49 | ||||
| -rw-r--r-- | tests/reflection/std430-layout.glsl.expected | 107 |
3 files changed, 186 insertions, 11 deletions
diff --git a/source/slang/type-layout.cpp b/source/slang/type-layout.cpp index fbaec3736..10c7327ce 100644 --- a/source/slang/type-layout.cpp +++ b/source/slang/type-layout.cpp @@ -155,20 +155,32 @@ struct GLSLConstantBufferLayoutRulesImpl : DefaultConstantBufferLayoutRulesImpl { }; +// The `std140` and `std430` rules require vectors to be aligned to the next power of +// two up from their size (so a `float2` is 8-byte aligned, and a `float3` is +// 16-byte aligned). +// +// Note that in this case we have a type layout where the size is *not* a multiple +// of the alignment, so it should be possible to pack a scalar after a `float3`. +static SimpleLayoutInfo getGLSLVectorLayout( + SimpleLayoutInfo elementInfo, size_t elementCount) +{ + assert(elementInfo.kind == LayoutResourceKind::Uniform); + auto size = elementInfo.size * elementCount; + SimpleLayoutInfo vectorInfo( + LayoutResourceKind::Uniform, + size, + RoundUpToPowerOfTwo(size)); + return vectorInfo; +} + +// The `std140` rules combine the GLSL-specific layout for 3-vectors with the +// alignment padding for structures and arrays that is common to both HLSL +// and GLSL constant buffers. struct Std140LayoutRulesImpl : GLSLConstantBufferLayoutRulesImpl { - // The `std140` rules require vectors to be aligned to the next power of two - // up from their size (so a `float2` is 8-byte aligned, and a `float3` is - // 16-byte aligned). SimpleLayoutInfo GetVectorLayout(SimpleLayoutInfo elementInfo, size_t elementCount) override { - assert(elementInfo.kind == LayoutResourceKind::Uniform); - auto size = elementInfo.size * elementCount; - SimpleLayoutInfo vectorInfo( - LayoutResourceKind::Uniform, - size, - RoundUpToPowerOfTwo(size)); - return vectorInfo; + return getGLSLVectorLayout(elementInfo, elementCount); } }; @@ -207,8 +219,15 @@ struct HLSLStructuredBufferLayoutRulesImpl : DefaultLayoutRulesImpl // TODO: customize these to be correct... }; -struct Std430LayoutRulesImpl : GLSLConstantBufferLayoutRulesImpl +// The `std430` rules don't include the array/structure alignment padding that +// gets applied to constant buffers, but they do include the padding of 3-vectors +// to be aligned as 4-vectors. +struct Std430LayoutRulesImpl : DefaultLayoutRulesImpl { + SimpleLayoutInfo GetVectorLayout(SimpleLayoutInfo elementInfo, size_t elementCount) override + { + return getGLSLVectorLayout(elementInfo, elementCount); + } }; struct DefaultVaryingLayoutRulesImpl : DefaultLayoutRulesImpl diff --git a/tests/reflection/std430-layout.glsl b/tests/reflection/std430-layout.glsl new file mode 100644 index 000000000..5d4dee88f --- /dev/null +++ b/tests/reflection/std430-layout.glsl @@ -0,0 +1,49 @@ +//TEST(smoke):SIMPLE:-profile ps_4_0 -target reflection-json + +// Confirm fix for GitHub issue #55 + +struct Foo +{ + vec2 f; +}; + +layout(set = 0, binding = 0) +buffer SomeBuffer +{ + // offset: 0, size: 4, alignment: 4 + float a; + + // offset: 16, size: 12, alignment: 16 + // + // Note that it can't immediately follow `a` + // bcause of its alignment + vec3 b; + + // offset: 28, size: 16, alignment: 4, stride: 4 + // + // This array can be densely packed and 4-byte aligned under `std430` rules + float c[4]; + + // offset: 48, size: 8, alignment: 8 + // + // This nees to be bumped up to a 8-byte aligned boundary + vec2 d; + + // offset: 56, size: 8, alignment: 8 + // + // This can come right after `d`, because `struct` types no longer + // get an artificial padding out to 16-byte alignment + Foo e; + + // offset: 64, size: 12: alignment: 16 + vec3 g; + + // offset: 76, size: 4, alignment: 4 + // + // This can fit in the empty space after `g` because we allow + // the size of a `vec3` to be smaller than its alignment + float h; +}; + +void main() +{} diff --git a/tests/reflection/std430-layout.glsl.expected b/tests/reflection/std430-layout.glsl.expected new file mode 100644 index 000000000..701a36909 --- /dev/null +++ b/tests/reflection/std430-layout.glsl.expected @@ -0,0 +1,107 @@ +result code = 0 +standard error = { +} +standard output = { +{ + "parameters": [ + { + "name": "SomeBuffer", + "binding": {"kind": "descriptorTableSlot", "index": 0}, + "type": { + "kind": "shaderStorageBuffer", + "elementType": { + "kind": "struct", + "fields": [ + { + "name": "a", + "type": { + "kind": "scalar", + "scalarType": "float32" + }, + "binding": {"kind": "uniform", "offset": 0, "size": 4} + }, + { + "name": "b", + "type": { + "kind": "vector", + "elementCount": 3, + "elementType": { + "kind": "scalar", + "scalarType": "float32" + } + }, + "binding": {"kind": "uniform", "offset": 16, "size": 12} + }, + { + "name": "c", + "type": { + "kind": "array", + "elementCount": 4, + "elementType": { + "kind": "scalar", + "scalarType": "float32" + }, + "uniformStride": 4 + }, + "binding": {"kind": "uniform", "offset": 28, "size": 16} + }, + { + "name": "d", + "type": { + "kind": "vector", + "elementCount": 2, + "elementType": { + "kind": "scalar", + "scalarType": "float32" + } + }, + "binding": {"kind": "uniform", "offset": 48, "size": 8} + }, + { + "name": "e", + "type": { + "kind": "struct", + "fields": [ + { + "name": "f", + "type": { + "kind": "vector", + "elementCount": 2, + "elementType": { + "kind": "scalar", + "scalarType": "float32" + } + }, + "binding": {"kind": "uniform", "offset": 0, "size": 8} + } + ] + }, + "binding": {"kind": "uniform", "offset": 56, "size": 8} + }, + { + "name": "g", + "type": { + "kind": "vector", + "elementCount": 3, + "elementType": { + "kind": "scalar", + "scalarType": "float32" + } + }, + "binding": {"kind": "uniform", "offset": 64, "size": 12} + }, + { + "name": "h", + "type": { + "kind": "scalar", + "scalarType": "float32" + }, + "binding": {"kind": "uniform", "offset": 76, "size": 4} + } + ] + } + } + } + ] +} +} |