Hash :
7e28089b
Author :
Date :
2025-07-31T18:44:01
WGSL: support bvecs in uniforms WGSL does not allow booleans in the uniform address space. The last CL uses u32s to represent bools in the uniform address space, and this CL uses vecN<u32> to represent bvecN. Bug: angleproject:376553328 Change-Id: Ibf9f1fbf230ca03dd3d4661ba599e5fb1cb26ac4 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6808955 Reviewed-by: Liza Burakova <liza@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Matthew Denton <mpdenton@chromium.org>
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//
// Copyright 2024 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
#include "compiler/translator/wgsl/Utils.h"
#include "common/log_utils.h"
#include "compiler/translator/BaseTypes.h"
#include "compiler/translator/Common.h"
#include "compiler/translator/ImmutableStringBuilder.h"
#include "compiler/translator/Symbol.h"
#include "compiler/translator/Types.h"
#include "compiler/translator/util.h"
namespace sh
{
namespace
{
const char kWrappedPrefix[] = "ANGLE_wrapped_";
}
template <typename StringStreamType>
void WriteWgslBareTypeName(StringStreamType &output,
const TType &type,
const EmitTypeConfig &config)
{
const TBasicType basicType = type.getBasicType();
switch (basicType)
{
case TBasicType::EbtVoid:
output << type.getBasicString();
break;
case TBasicType::EbtBool:
if (config.addressSpace == WgslAddressSpace::Uniform)
{
// The uniform address space does not support bools in WGSL, so they are emulated
// with u32 (which matches gles because bools are 4-bytes long in std140).
output << "u32";
}
else
{
output << "bool";
}
break;
// TODO(anglebug.com/42267100): is there double precision (f64) in GLSL? It doesn't really
// exist in WGSL (i.e. f64 does not exist but AbstractFloat can handle 64 bits???) Metal
// does not have 64 bit double precision types. It's being implemented in WGPU:
// https://github.com/gpuweb/gpuweb/issues/2805
case TBasicType::EbtFloat:
output << "f32";
break;
case TBasicType::EbtInt:
output << "i32";
break;
case TBasicType::EbtUInt:
output << "u32";
break;
case TBasicType::EbtStruct:
WriteNameOf(output, *type.getStruct());
break;
case TBasicType::EbtInterfaceBlock:
WriteNameOf(output, *type.getInterfaceBlock());
break;
default:
if (IsSampler(basicType))
{
// Variables of sampler type should be written elsewhere since they require special
// handling; they are split into two different variables in WGSL.
// TODO(anglebug.com/389145696): this is reachable if a sampler is passed as a
// function parameter. They should be monomorphized.
UNIMPLEMENTED();
}
else if (IsImage(basicType))
{
// GLSL's image types are not implemented in this backend.
UNIMPLEMENTED();
output << "texture_storage_2d<";
switch (type.getBasicType())
{
case EbtImage2D:
output << "f32";
break;
case EbtIImage2D:
output << "i32";
break;
case EbtUImage2D:
output << "u32";
break;
default:
UNIMPLEMENTED();
break;
}
if (type.getMemoryQualifier().readonly || type.getMemoryQualifier().writeonly)
{
UNIMPLEMENTED();
}
output << ">";
}
else
{
UNREACHABLE();
}
break;
}
}
template <typename StringStreamType>
void WriteNameOf(StringStreamType &output, SymbolType symbolType, const ImmutableString &name)
{
switch (symbolType)
{
case SymbolType::BuiltIn:
output << name;
break;
case SymbolType::UserDefined:
output << '_' << kUserDefinedNamePrefix << name;
break;
case SymbolType::AngleInternal:
output << name;
break;
case SymbolType::Empty:
// TODO(anglebug.com/42267100): support this if necessary
UNREACHABLE();
}
}
template <typename StringStreamType>
void WriteWgslType(StringStreamType &output, const TType &type, const EmitTypeConfig &config)
{
if (type.isArray())
{
// WGSL does not support samplers anywhere inside structs or arrays.
ASSERT(!type.isSampler() && !type.isStructureContainingSamplers());
// Examples:
// array<f32, 5>
// array<array<u32, 5>, 10>
output << "array<";
TType innerType = type;
innerType.toArrayElementType();
if (ElementTypeNeedsUniformWrapperStruct(config.addressSpace == WgslAddressSpace::Uniform,
&type))
{
// Multidimensional arrays not currently supported in uniforms in the WebGPU backend
ASSERT(!innerType.isArray());
// Due to uniform address space layout constraints, certain array element types must
// be wrapped in a wrapper struct.
// Example: array<ANGLE_wrapped_f32, 5>
output << MakeUniformWrapperStructName(&innerType);
}
else
{
WriteWgslType(output, innerType, config);
}
output << ", " << type.getOutermostArraySize() << ">";
}
else if (type.isVector())
{
output << "vec" << static_cast<uint32_t>(type.getNominalSize()) << "<";
WriteWgslBareTypeName(output, type, config);
output << ">";
}
else if (type.isMatrix())
{
if (config.addressSpace == WgslAddressSpace::Uniform && type.getRows() == 2)
{
// matCx2 in the uniform address space is too packed for std140, and so they will be
// represented by an array<ANGLE_wrapped_vec2, C>.
output << "array<" << kWrappedPrefix << "vec2, "
<< static_cast<uint32_t>(type.getCols()) << ">";
}
else
{
output << "mat" << static_cast<uint32_t>(type.getCols()) << "x"
<< static_cast<uint32_t>(type.getRows()) << "<";
WriteWgslBareTypeName(output, type, config);
output << ">";
}
}
else
{
// This type has no dimensions and is equivalent to its bare type.
WriteWgslBareTypeName(output, type, config);
}
}
template void WriteWgslBareTypeName<TInfoSinkBase>(TInfoSinkBase &output,
const TType &type,
const EmitTypeConfig &config);
template void WriteNameOf<TInfoSinkBase>(TInfoSinkBase &output,
SymbolType symbolType,
const ImmutableString &name);
template void WriteWgslType<TInfoSinkBase>(TInfoSinkBase &output,
const TType &type,
const EmitTypeConfig &config);
template void WriteWgslBareTypeName<TStringStream>(TStringStream &output,
const TType &type,
const EmitTypeConfig &config);
template void WriteNameOf<TStringStream>(TStringStream &output,
SymbolType symbolType,
const ImmutableString &name);
template void WriteWgslType<TStringStream>(TStringStream &output,
const TType &type,
const EmitTypeConfig &config);
template <typename StringStreamType>
void WriteWgslSamplerType(StringStreamType &output,
const TType &type,
WgslSamplerTypeConfig samplerType)
{
ASSERT(type.isSampler());
if (samplerType == WgslSamplerTypeConfig::Texture)
{
output << "texture";
if (IsShadowSampler(type.getBasicType()))
{
output << "_depth";
}
if (IsSamplerMS(type.getBasicType()))
{
output << "_multisampled";
ASSERT(IsSampler2D(type.getBasicType()));
// Unsupported in wGSL, it seems.
ASSERT(!IsSampler2DMSArray(type.getBasicType()));
}
if (IsSampler2D(type.getBasicType()) || IsSampler2DArray(type.getBasicType()))
{
output << "_2d";
}
else if (IsSampler3D(type.getBasicType()))
{
output << "_3d";
}
else if (IsSamplerCube(type.getBasicType()))
{
output << "_cube";
}
if (IsSamplerArray(type.getBasicType()))
{
ASSERT(!IsSampler3D(type.getBasicType()));
output << "_array";
}
// Shadow samplers are always floating point in both GLSL and WGSL and don't need to be
// parameterized.
if (!IsShadowSampler(type.getBasicType()))
{
output << "<";
if (!IsIntegerSampler(type.getBasicType()))
{
output << "f32";
}
else if (!IsIntegerSamplerUnsigned(type.getBasicType()))
{
output << "i32";
}
else
{
output << "u32";
}
output << ">";
}
if (type.getMemoryQualifier().readonly || type.getMemoryQualifier().writeonly)
{
// TODO(anglebug.com/42267100): implement memory qualifiers.
UNIMPLEMENTED();
}
}
else
{
ASSERT(samplerType == WgslSamplerTypeConfig::Sampler);
// sampler or sampler_comparison.
if (IsShadowSampler(type.getBasicType()))
{
output << "sampler_comparison";
}
else
{
output << "sampler";
}
}
}
template void WriteWgslSamplerType<TInfoSinkBase>(TInfoSinkBase &output,
const TType &type,
WgslSamplerTypeConfig samplerType);
template void WriteWgslSamplerType<TStringStream>(TStringStream &output,
const TType &type,
WgslSamplerTypeConfig samplerType);
ImmutableString MakeUniformWrapperStructName(const TType *type)
{
TType typeToOutput(*type);
const char *typeStr;
// Bools are represented as u32s in the uniform address space (and bvecs as uvecs).
// TODO(anglebug.com/376553328): simplify by using WriteWgslType({WgslAddressSpace::Uniform})
// here.
if (typeToOutput.getBasicType() == EbtBool)
{
typeToOutput.setBasicType(TBasicType::EbtUInt);
}
typeStr = typeToOutput.getBuiltInTypeNameString();
return BuildConcatenatedImmutableString(kWrappedPrefix, typeStr);
}
bool ElementTypeNeedsUniformWrapperStruct(bool inUniformAddressSpace, const TType *type)
{
// Only types that are used as array element types in the uniform address space need wrapper
// structs. If the array element type is a struct it does not need to be wrapped in another
// layer of struct.
if (!inUniformAddressSpace || !type->isArray() || type->getStruct())
{
return false;
}
TType elementType = *type;
elementType.toArrayElementType();
// If the array element type's stride is already a multiple of 16, it does not need a wrapper
// struct.
//
// The remaining possible element types are scalars, vectors, matrices, and other arrays.
// - Scalars need to be aligned to 16.
// - vec3 and vec4 are already aligned to 16, but vec2 needs to be aligned.
// - Matrices are aligned to 16 automatically, except matCx2 which already needs to be handled
// by specialized code anyway.
// - WebGL2 doesn't support nested arrays so this won't either.
ASSERT(!elementType.isArray());
return elementType.isScalar() || (elementType.isVector() && elementType.getNominalSize() == 2);
}
GlobalVars FindGlobalVars(TIntermBlock *root)
{
GlobalVars globals;
for (TIntermNode *node : *root->getSequence())
{
if (TIntermDeclaration *declNode = node->getAsDeclarationNode())
{
Declaration decl = ViewDeclaration(*declNode);
globals.insert({decl.symbol.variable().name(), declNode});
}
}
return globals;
}
} // namespace sh