Implement function

Author: luciechoi

tools/clang/lib/AST/ASTContextHLSL.cpp

@@ -1434,6 +1434,18 @@ CXXRecordDecl *hlsl::DeclareVkSampledTexture2DType(ASTContext &context,
       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;
 }

tools/clang/lib/SPIRV/SpirvEmitter.cpp

@@ -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 =

tools/clang/test/CodeGenSPIRV/vk.sampledtexture.calculate-lod.hlsl

@@ -0,0 +1,21 @@
+// RUN: %dxc -T ps_6_0 -E main -fcgl  %s -spirv | FileCheck %s
+
+// CHECK: OpCapability ImageQuery
+
+vk::SampledTexture2D<float4> t1 : register(t0);
+
+// CHECK: %type_2d_image = OpTypeImage %float 2D 0 0 0 1 Unknown
+// CHECK: %type_sampled_image = OpTypeSampledImage %type_2d_image
+// CHECK: [[ptr:%[a-zA-Z0-9_]+]] = OpTypePointer UniformConstant %type_sampled_image
+
+// CHECK: %t1 = OpVariable [[ptr]] UniformConstant
+
+void main() {
+  float2 xy = float2(0.5, 0.5);
+
+//CHECK:          [[tex1:%[a-zA-Z0-9_]+]] = OpLoad %type_sampled_image %t1
+//CHECK-NEXT:    [[xy_load:%[a-zA-Z0-9_]+]] = OpLoad %v2float %xy
+//CHECK-NEXT: [[query:%[a-zA-Z0-9_]+]] = OpImageQueryLod %v2float [[tex1]] [[xy_load]]
+//CHECK-NEXT:        {{%[0-9]+}} = OpCompositeExtract %float [[query]] 0
+  float lod = t1.CalculateLevelOfDetail(xy);
+}