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[SPIR-V] Add vk::SampledTexture2D resource type and .Sample(), .CalculateLevelOfDetail() method. #8047

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[SPIR-V] Add vk::SampledTexture2D resource type and .Sample(), .CalculateLevelOfDetail() method. #8047

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6c73c17
Implement `vk::SampledTexture2D` type and `Sample` method.
luciechoi Jan 7, 2026
4c95db3
Implement optional arguments
luciechoi Jan 8, 2026
03b6051
Implement CalculateLevelOfDetail
luciechoi Jan 9, 2026
389cd0f
formatting
luciechoi Jan 9, 2026
e6d978f
Address comments
luciechoi Jan 22, 2026
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3 changes: 2 additions & 1 deletion include/dxc/dxcapi.internal.h
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Expand Up @@ -136,7 +136,8 @@ enum LEGAL_INTRINSIC_COMPTYPES {

#ifdef ENABLE_SPIRV_CODEGEN
LICOMPTYPE_VK_BUFFER_POINTER = 54,
LICOMPTYPE_COUNT = 55
LICOMPTYPE_VK_SAMPLED_TEXTURE2D = 55,
LICOMPTYPE_COUNT = 56
#else
LICOMPTYPE_COUNT = 54
#endif
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5 changes: 5 additions & 0 deletions tools/clang/include/clang/AST/HlslTypes.h
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Expand Up @@ -407,6 +407,11 @@ clang::CXXRecordDecl *
DeclareVkBufferPointerType(clang::ASTContext &context,
clang::DeclContext *declContext);

clang::CXXRecordDecl *DeclareVkSampledTexture2DType(
clang::ASTContext &context, clang::DeclContext *declContext,
clang::QualType float2Type, clang::QualType int2Type,
clang::QualType float4Type);

clang::CXXRecordDecl *DeclareInlineSpirvType(clang::ASTContext &context,
clang::DeclContext *declContext,
llvm::StringRef typeName,
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3 changes: 3 additions & 0 deletions tools/clang/include/clang/SPIRV/AstTypeProbe.h
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Expand Up @@ -257,6 +257,9 @@ bool isTexture(QualType);
/// Texture2DMSArray type.
bool isTextureMS(QualType);

/// \brief Returns true if the given type is an HLSL SampledTexture type.
bool isSampledTexture(QualType);

/// \brief Returns true if the given type is an HLSL RWTexture type.
bool isRWTexture(QualType);

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3 changes: 3 additions & 0 deletions tools/clang/include/clang/SPIRV/SpirvBuilder.h
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Expand Up @@ -286,6 +286,9 @@ class SpirvBuilder {
/// If compareVal is given a non-zero value, *Dref* variants of OpImageSample*
/// will be generated.
///
/// If imageType is not a sampled image type, the OpSampledImage* instructions
/// will be generated.
///
/// If lod or grad is given a non-zero value, *ExplicitLod variants of
/// OpImageSample* will be generated; otherwise, *ImplicitLod variant will
/// be generated.
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80 changes: 80 additions & 0 deletions tools/clang/lib/AST/ASTContextHLSL.cpp
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Expand Up @@ -1369,6 +1369,86 @@ CXXRecordDecl *hlsl::DeclareNodeOrRecordType(
}

#ifdef ENABLE_SPIRV_CODEGEN
CXXRecordDecl *hlsl::DeclareVkSampledTexture2DType(ASTContext &context,
DeclContext *declContext,
QualType float2Type,
QualType int2Type,
QualType float4Type) {
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@s-perron s-perron Jan 18, 2026

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Are you planning on make this function more general? For example could float2Type become CoordinateType? Then for Textur3D it is just a float?

If not, why pass these in as parameters? Could we simplify the interface an build them in this function?

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@luciechoi luciechoi Jan 22, 2026

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Right, generalized the function to take in other SampledTexture types, and pass in the return type and the argument types.

BuiltinTypeDeclBuilder Builder(declContext, "SampledTexture2D",
TagDecl::TagKind::TTK_Struct);

QualType defaultTextureType = float4Type;
TemplateTypeParmDecl *TyParamDecl =
Builder.addTypeTemplateParam("SampledTextureType", defaultTextureType);

Builder.startDefinition();

QualType paramType = QualType(TyParamDecl->getTypeForDecl(), 0);
CXXRecordDecl *recordDecl = Builder.getRecordDecl();

QualType floatType = context.FloatTy;
QualType uintType = context.UnsignedIntTy;
// Add Sample method
// Sample(location)
CXXMethodDecl *sampleDecl = CreateObjectFunctionDeclarationWithParams(
context, recordDecl, paramType, ArrayRef<QualType>(float2Type),
ArrayRef<StringRef>(StringRef("location")),
context.DeclarationNames.getIdentifier(&context.Idents.get("Sample")),
/*isConst*/ true);
sampleDecl->addAttr(HLSLIntrinsicAttr::CreateImplicit(
context, "op", "", static_cast<int>(hlsl::IntrinsicOp::MOP_Sample)));
sampleDecl->addAttr(HLSLCXXOverloadAttr::CreateImplicit(context));

// Sample(location, offset)
QualType params2[] = {float2Type, int2Type};
StringRef names2[] = {"location", "offset"};
CXXMethodDecl *sampleDecl2 = CreateObjectFunctionDeclarationWithParams(
context, recordDecl, paramType, params2, names2,
context.DeclarationNames.getIdentifier(&context.Idents.get("Sample")),
/*isConst*/ true);
sampleDecl2->addAttr(HLSLIntrinsicAttr::CreateImplicit(
context, "op", "", static_cast<int>(hlsl::IntrinsicOp::MOP_Sample)));
sampleDecl2->addAttr(HLSLCXXOverloadAttr::CreateImplicit(context));

// Sample(location, offset, clamp)
QualType params3[] = {float2Type, int2Type, floatType};
StringRef names3[] = {"location", "offset", "clamp"};
CXXMethodDecl *sampleDecl3 = CreateObjectFunctionDeclarationWithParams(
context, recordDecl, paramType, params3, names3,
context.DeclarationNames.getIdentifier(&context.Idents.get("Sample")),
/*isConst*/ true);
sampleDecl3->addAttr(HLSLIntrinsicAttr::CreateImplicit(
context, "op", "", static_cast<int>(hlsl::IntrinsicOp::MOP_Sample)));
sampleDecl3->addAttr(HLSLCXXOverloadAttr::CreateImplicit(context));

// Sample(location, offset, clamp, status)
QualType params4[] = {float2Type, int2Type, floatType,
context.getLValueReferenceType(uintType)};
StringRef names4[] = {"location", "offset", "clamp", "status"};
CXXMethodDecl *sampleDecl4 = CreateObjectFunctionDeclarationWithParams(
context, recordDecl, paramType, params4, names4,
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This function will be come very big. Could you break it up into smaller functions? This block could be its own. Call it addSampeFunction. You can group other functions in the same way.

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@luciechoi luciechoi Jan 22, 2026

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Sounds good, separated them into helpers.

context.DeclarationNames.getIdentifier(&context.Idents.get("Sample")),
/*isConst*/ true);
sampleDecl4->addAttr(HLSLIntrinsicAttr::CreateImplicit(
context, "op", "", static_cast<int>(hlsl::IntrinsicOp::MOP_Sample)));
sampleDecl4->addAttr(HLSLCXXOverloadAttr::CreateImplicit(context));

// CalculateLevelOfDetail(location)
CXXMethodDecl *lodDecl = CreateObjectFunctionDeclarationWithParams(
context, recordDecl, floatType, ArrayRef<QualType>(float2Type),
ArrayRef<StringRef>(StringRef("location")),
context.DeclarationNames.getIdentifier(
&context.Idents.get("CalculateLevelOfDetail")),
/*isConst*/ true);
lodDecl->addAttr(HLSLIntrinsicAttr::CreateImplicit(
context, "op", "",
static_cast<int>(hlsl::IntrinsicOp::MOP_CalculateLevelOfDetail)));
lodDecl->addAttr(HLSLCXXOverloadAttr::CreateImplicit(context));

Builder.completeDefinition();
return recordDecl;
}

CXXRecordDecl *hlsl::DeclareVkBufferPointerType(ASTContext &context,
DeclContext *declContext) {
BuiltinTypeDeclBuilder Builder(declContext, "BufferPointer",
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11 changes: 11 additions & 0 deletions tools/clang/lib/SPIRV/AstTypeProbe.cpp
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Expand Up @@ -926,6 +926,17 @@ bool isTexture(QualType type) {
return false;
}

bool isSampledTexture(QualType type) {
if (const auto *rt = type->getAs<RecordType>()) {
const auto name = rt->getDecl()->getName();
// TODO(https://github.com/microsoft/DirectXShaderCompiler/issues/7979): Add
// other sampled texture types as needed.
if (name == "SampledTexture2D")
return true;
}
return false;
}

bool isTextureMS(QualType type) {
if (const auto *rt = type->getAs<RecordType>()) {
const auto name = rt->getDecl()->getName();
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16 changes: 16 additions & 0 deletions tools/clang/lib/SPIRV/LowerTypeVisitor.cpp
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Expand Up @@ -849,6 +849,22 @@ const SpirvType *LowerTypeVisitor::lowerVkTypeInVkNamespace(
assert(visitedTypeStack.size() == visitedTypeStackSize);
return pointerType;
}
if (name == "SampledTexture2D") {
const auto sampledType = hlsl::GetHLSLResourceResultType(type);
auto loweredType = lowerType(getElementType(astContext, sampledType), rule,
/*isRowMajor*/ llvm::None, srcLoc);

// Treat bool textures as uint for compatibility with OpTypeImage.
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It's not about compatibility with OpTypeImage. Bool does not have a defined size in SPIR-V, so it cannot be used in the external interface.

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@luciechoi luciechoi Jan 22, 2026

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Updated the comment.

if (loweredType == spvContext.getBoolType()) {
loweredType = spvContext.getUIntType(32);
}

const auto *imageType = spvContext.getImageType(
loweredType, spv::Dim::Dim2D, ImageType::WithDepth::No,
false /* array */, false /* ms */, ImageType::WithSampler::Yes,
spv::ImageFormat::Unknown);
return spvContext.getSampledImageType(imageType);
}
emitError("unknown type %0 in vk namespace", srcLoc) << type;
return nullptr;
}
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11 changes: 9 additions & 2 deletions tools/clang/lib/SPIRV/SpirvBuilder.cpp
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Expand Up @@ -620,8 +620,15 @@ SpirvInstruction *SpirvBuilder::createImageSample(
assert(lod == nullptr || minLod == nullptr);

// An OpSampledImage is required to do the image sampling.
auto *sampledImage =
createSampledImage(imageType, image, sampler, loc, range);
// Skip creating OpSampledImage if the imageType is a sampled texture.
SpirvInstruction *sampledImage = nullptr;
if (isSampledTexture(imageType)) {
assert(!sampler &&
"sampler must be null when sampling from a sampled texture");
sampledImage = image;
} else {
sampledImage = createSampledImage(imageType, image, sampler, loc, range);
}

const auto mask = composeImageOperandsMask(
bias, lod, grad, constOffset, varOffset, constOffsets, sample, minLod);
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75 changes: 60 additions & 15 deletions tools/clang/lib/SPIRV/SpirvEmitter.cpp
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Expand Up @@ -4451,15 +4451,25 @@ SpirvEmitter::processTextureLevelOfDetail(const CXXMemberCallExpr *expr,
// Texture2D(Array).CalculateLevelOfDetail(SamplerState S, float2 xy);
// TextureCube(Array).CalculateLevelOfDetail(SamplerState S, float3 xyz);
// Texture3D.CalculateLevelOfDetail(SamplerState S, float3 xyz);
// SampledTexture2D.CalculateLevelOfDetail(float2 xy);
// Return type is always a single float (LOD).
assert(expr->getNumArgs() == 2u);
const auto *object = expr->getImplicitObjectArgument();
auto *objectInfo = loadIfGLValue(object);
auto *samplerState = doExpr(expr->getArg(0));
auto *coordinate = doExpr(expr->getArg(1));

auto *sampledImage = spvBuilder.createSampledImage(
object->getType(), objectInfo, samplerState, expr->getExprLoc());
const auto *imageExpr = expr->getImplicitObjectArgument();
const QualType imageType = imageExpr->getType();
// numarg is 1 if isSampledTexture(imageType). otherwise 2.
assert(expr->getNumArgs() == (isSampledTexture(imageType) ? 1u : 2u));

auto *objectInfo = loadIfGLValue(imageExpr);
auto *samplerState =
isSampledTexture(imageType) ? nullptr : doExpr(expr->getArg(0));
auto *coordinate = isSampledTexture(imageType) ? doExpr(expr->getArg(0))
: doExpr(expr->getArg(1));

auto *sampledImage =
isSampledTexture(imageType)
? objectInfo
: spvBuilder.createSampledImage(imageExpr->getType(), objectInfo,
samplerState, expr->getExprLoc());

// The result type of OpImageQueryLod must be a float2.
const QualType queryResultType =
Expand Down Expand Up @@ -5812,11 +5822,54 @@ SpirvEmitter::processTextureSampleGather(const CXXMemberCallExpr *expr,
// float2|3|4 Location
// [, uint Status]);
//
// For SampledTexture2D:
// DXGI_FORMAT Object.Sample(float Location
// [, int Offset]
// [, float Clamp]
// [, out uint Status]);
//
// Other Texture types do not have a Gather method.

const auto numArgs = expr->getNumArgs();
const auto loc = expr->getExprLoc();
const auto range = expr->getSourceRange();

const auto *imageExpr = expr->getImplicitObjectArgument();
const QualType imageType = imageExpr->getType();

if (isSampledTexture(imageType)) {
auto *sampledImage = loadIfGLValue(imageExpr);
auto *coordinate = doExpr(expr->getArg(0));
SpirvInstruction *constOffset = nullptr;
SpirvInstruction *varOffset = nullptr;
SpirvInstruction *clamp = nullptr;
SpirvInstruction *status = nullptr;

if (numArgs > 1) {
handleOffsetInMethodCall(expr, 1, &constOffset, &varOffset);
}
if (numArgs > 2) {
clamp = doExpr(expr->getArg(2));
}
if (numArgs > 3) {
status = doExpr(expr->getArg(3));
}
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@s-perron s-perron Jan 18, 2026

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You eventually going to have to add all of the checks below when you add all of the appropriate overload. We should try to avoid adding duplicating the argument parsing here.

You could try doing:

uint offset = 0;
auto *image = loadIfGLValue(imageExpr);
auto *sampler = nullptr;

if (!isSampledTexture(imageType)) {
  sampler = doExpr(expr->getArg(0));
  offset = 1;
}

Then all of the later accesses become to expr->getArg(offset + ); For example:

auto *coordinate = doExpr(expr->getArg(offset));

This will avoid repeating the logic.

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@luciechoi luciechoi Jan 22, 2026

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Thanks for the suggestion. I restructured and explicitly stated the indices.

  int samplerIndex, clampIndex, coordIndex, offsetIndex;
  if (isImageSampledTexture) {
    samplerIndex = -1; // non-existant
    coordIndex = 0;
    offsetIndex = 1;
    clampIndex = 2;
  } else {
    samplerIndex = 0;
    coordIndex = 1;
    offsetIndex = 2;
    clampIndex = 3;
  }

This way, I was able to keep some operations in order so the existing tests don't have to be modified.


const auto retType = expr->getDirectCallee()->getReturnType();
return createImageSample(
retType, imageType, sampledImage, /*sampler*/ nullptr, coordinate,
/*compareVal*/ nullptr, /*bias*/ nullptr,
/*lod*/ nullptr, {nullptr, nullptr}, constOffset, varOffset,
/*constOffsets*/ nullptr, /*sample*/ nullptr,
/*minLod*/ clamp, status, loc, range);
}

auto *image = loadIfGLValue(imageExpr);
auto *sampler = doExpr(expr->getArg(0));
auto *coordinate = doExpr(expr->getArg(1));
// .Sample()/.Gather() may have a third optional paramter for offset.
SpirvInstruction *constOffset = nullptr, *varOffset = nullptr;

const bool hasStatusArg =
expr->getArg(numArgs - 1)->getType()->isUnsignedIntegerType();

Expand All @@ -5832,14 +5885,6 @@ SpirvEmitter::processTextureSampleGather(const CXXMemberCallExpr *expr,
// Subtract 1 for status (if it exists), subtract 1 for clamp (if it exists),
// and subtract 2 for sampler_state and location.
const bool hasOffsetArg = numArgs - hasStatusArg - hasClampArg - 2 > 0;

const auto *imageExpr = expr->getImplicitObjectArgument();
const QualType imageType = imageExpr->getType();
auto *image = loadIfGLValue(imageExpr);
auto *sampler = doExpr(expr->getArg(0));
auto *coordinate = doExpr(expr->getArg(1));
// .Sample()/.Gather() may have a third optional paramter for offset.
SpirvInstruction *constOffset = nullptr, *varOffset = nullptr;
if (hasOffsetArg)
handleOffsetInMethodCall(expr, 2, &constOffset, &varOffset);

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