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

luciechoi · 2026-01-07T08:12:13Z

Part of #7979

Add SampledTexture2D resource type in the vk namespace.
Add .Sample(float2 location) method.
Add default type parameter float4.
Allow optional arguments int2 offset, float clamp, uint status.
Add .CalculateLevelOfDetail(float2 location) method.

github-actions · 2026-01-07T08:13:20Z

✅ With the latest revision this PR passed the C/C++ code formatter.

s-perron

This seems like a reasonable direction. There are some issues that we need to figure out how to handle.

s-perron · 2026-01-07T20:47:29Z

tools/clang/test/CodeGenSPIRV/vk.sampledtexture2d.hlsl

+// CHECK: [[in_var_TEXCOORD:%[a-zA-Z0-9_]+]] = OpVariable %_ptr_Input_v2float Input
+// CHECK: [[out_var_SV_Target:%[a-zA-Z0-9_]+]] = OpVariable %_ptr_Output_v4float Output
+
+vk::SampledTexture2D<float4> tex : register(t0);


Could you test this with an int so it is different then the next test? That we will know if you accidentally always output a float type.

Thanks for pointing out, added a test for vk::SampledTexture2D<uint> type.

tools/clang/lib/AST/HlslTypes.cpp

s-perron · 2026-01-07T20:51:51Z

tools/clang/lib/Sema/SemaHLSL.cpp

+        QualType float4Type =
+            LookupVectorType(HLSLScalarType::HLSLScalarType_float, 4);
+        recordDecl = DeclareVkSampledTexture2DType(*m_context, m_vkNSDecl,
+                                                   float2Type, float4Type);


Does the result of the sample have to be a 4 element vector? What happens if the template type is a scalar?

Right, if a template type is scalar, the results are extracted. Added a test.

s-perron · 2026-01-07T20:55:13Z

tools/clang/lib/SPIRV/SpirvBuilder.cpp

+  if (isSampledTexture(imageType)) {
+    sampledImage = image;


Should we assert that the sampler is false? Not necessary, but this function has a complicated interface, and it could be easy to use it incorrectly.

Is there documentation for this function to update?

Should we assert that the sampler is false?

Added.

Is there documentation for this function to update?

Updated the function documentation.

luciechoi · 2026-01-08T05:03:51Z

Thanks for the early review! I've updated the method to take in optional arguments.

damyanp · 2026-01-12T23:18:22Z

If this is worth mentioning in the release notes, please add something to https://github.com/microsoft/DirectXShaderCompiler/blob/main/docs/ReleaseNotes.md as appropriate.

s-perron

This looks really good to me. A few minor code style issues to fix up.

s-perron · 2026-01-18T00:42:29Z

tools/clang/include/clang/SPIRV/SpirvBuilder.h

+  /// If imageType is not a sampled image type, the OpSampledImage* instructions
+  /// will be generated.
+  ///


This is confusing. Can you rephrase?

Suggested change

/// If imageType is not a sampled image type, the OpSampledImage* instructions

/// will be generated.

///

/// If the of `image` is a sampled image, then that image will be sampled. In this case, `sampler` must be `nullptr`. If `image` is not a sampled image, a sampled image will be create by combining `image` and `sampler`.

///

You'll need to fix the formatting.

s-perron · 2026-01-18T00:50:28Z

tools/clang/lib/AST/ASTContextHLSL.cpp

+  // 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,


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.

s-perron · 2026-01-18T00:52:23Z

tools/clang/lib/Sema/SemaHLSL.cpp

+      } else if (kind == AR_OBJECT_VK_SAMPLED_TEXTURE2D) {
+        if (!m_vkNSDecl)
+          continue;
+        recordDecl = DeclareVkSampledTexture2DType(
+            *m_context, m_vkNSDecl,
+            LookupVectorType(HLSLScalarType::HLSLScalarType_float, 2),
+            LookupVectorType(HLSLScalarType::HLSLScalarType_int, 2),
+            LookupVectorType(HLSLScalarType::HLSLScalarType_float, 4));
+        recordDecl->setImplicit(true);
+        m_vkSampledTexture2DTemplateDecl =
+            recordDecl->getDescribedClassTemplate();


You should add some tests in sema that look for errors. What if an invalid type is given as a template parameter?

s-perron · 2026-01-18T00:56:23Z

tools/clang/lib/AST/ASTContextHLSL.cpp

+                                                   QualType float2Type,
+                                                   QualType int2Type,
+                                                   QualType float4Type) {


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?

s-perron · 2026-01-18T00:58:54Z

tools/clang/lib/SPIRV/LowerTypeVisitor.cpp

+    auto loweredType = lowerType(getElementType(astContext, sampledType), rule,
+                                 /*isRowMajor*/ llvm::None, srcLoc);
+
+    // Treat bool textures as uint for compatibility with OpTypeImage.


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.

s-perron · 2026-01-18T01:01:01Z

tools/clang/lib/SPIRV/SpirvEmitter.cpp

+  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)


You are checking isSampledTextured a lot in this code. You should just use a single if-statement.

s-perron · 2026-01-18T01:08:11Z

tools/clang/lib/SPIRV/SpirvEmitter.cpp

+    if (numArgs > 1) {
+      handleOffsetInMethodCall(expr, 1, &constOffset, &varOffset);
+    }
+    if (numArgs > 2) {
+      clamp = doExpr(expr->getArg(2));
+    }
+    if (numArgs > 3) {
+      status = doExpr(expr->getArg(3));
+    }


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.

s-perron · 2026-01-18T01:11:46Z

If this is worth mentioning in the release notes, please add something to https://github.com/microsoft/DirectXShaderCompiler/blob/main/docs/ReleaseNotes.md as appropriate.

It will not be fully completed for this release. We should mention it in the next.

github-project-automation bot added this to HLSL Roadmap Jan 7, 2026

github-project-automation bot moved this to New in HLSL Roadmap Jan 7, 2026

luciechoi requested a review from s-perron January 7, 2026 08:13

luciechoi marked this pull request as draft January 7, 2026 09:03

s-perron reviewed Jan 7, 2026

View reviewed changes

luciechoi force-pushed the sampledtexture2d branch 3 times, most recently from 67fef39 to 8030b4e Compare January 8, 2026 04:56

luciechoi marked this pull request as ready for review January 8, 2026 05:03

luciechoi requested a review from s-perron January 8, 2026 05:06

luciechoi changed the title ~~[SPIR-V] Add vk::SampledTexture2D resource type and .Sample() method.~~ [SPIR-V] Add vk::SampledTexture2D resource type and .Sample(), CalculateLevelOfDetail() method. Jan 9, 2026

luciechoi changed the title ~~[SPIR-V] Add vk::SampledTexture2D resource type and .Sample(), CalculateLevelOfDetail() method.~~ [SPIR-V] Add vk::SampledTexture2D resource type and .Sample(), .CalculateLevelOfDetail() method. Jan 9, 2026

luciechoi added 2 commits January 9, 2026 10:22

Implement vk::SampledTexture2D type and Sample method.

6c73c17

Implement optional arguments

4c95db3

luciechoi force-pushed the sampledtexture2d branch from 6bc83c2 to eb29b1b Compare January 9, 2026 10:22

Implement CalculateLevelOfDetail

03b6051

luciechoi force-pushed the sampledtexture2d branch from eb29b1b to 03b6051 Compare January 9, 2026 10:25

formatting

389cd0f

luciechoi force-pushed the sampledtexture2d branch from ea6ac39 to 389cd0f Compare January 9, 2026 11:10

s-perron reviewed Jan 18, 2026

View reviewed changes

s-perron requested a review from llvm-beanz January 18, 2026 01:11

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

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

luciechoi commented Jan 7, 2026 •

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