Implement the ObjectRayDirection HLSL Function

[farzonl]

• Implement ObjectRayDirection clang builtin,
• Link ObjectRayDirection clang builtin with hlsl_intrinsics.h
• Add sema checks for ObjectRayDirection to CheckHLSLBuiltinFunctionCall in SemaChecking.cpp
• Add codegen for ObjectRayDirection to EmitHLSLBuiltinExpr in CGBuiltin.cpp
• Add codegen tests to clang/test/CodeGenHLSL/builtins/ObjectRayDirection.hlsl
• Add sema tests to clang/test/SemaHLSL/BuiltIns/ObjectRayDirection-errors.hlsl
• Create the int_dx_ObjectRayDirection intrinsic in IntrinsicsDirectX.td
• Create the DXILOpMapping of int_dx_ObjectRayDirection to 150 in DXIL.td
• Create the ObjectRayDirection.ll and ObjectRayDirection_errors.ll tests in llvm/test/CodeGen/DirectX/
• Create the int_spv_ObjectRayDirection intrinsic in IntrinsicsSPIRV.td
• In SPIRVInstructionSelector.cpp create the ObjectRayDirection lowering and map it to int_spv_ObjectRayDirection in SPIRVInstructionSelector::selectIntrinsic.
• Create SPIR-V backend test case in llvm/test/CodeGen/SPIRV/hlsl-intrinsics/ObjectRayDirection.ll

DirectX

DXIL Opcode	DXIL OpName	Shader Model	Shader Stages
150	ObjectRayDirection	6.3	('library', 'intersection', 'anyhit', 'closesthit')

SPIR-V

ObjectRayDirectionKHR

Short Description

ObjectRayDirectionKHR - Ray direction in object space

Description

ObjectRayDirectionKHR
A variable decorated with the ObjectRayDirectionKHR decoration will
specify the direction of the ray being processed, in object space.

Valid Usage

• 
  
  VUID-ObjectRayDirectionKHR-ObjectRayDirectionKHR-04299
  The ObjectRayDirectionKHR decoration must be used only within
  the IntersectionKHR , AnyHitKHR , or ClosestHitKHR
Execution Model

• 
  
  VUID-ObjectRayDirectionKHR-ObjectRayDirectionKHR-04300
  The variable decorated with ObjectRayDirectionKHR must be
  declared using the Input Storage Class

• 
  
  VUID-ObjectRayDirectionKHR-ObjectRayDirectionKHR-04301
  The variable decorated with ObjectRayDirectionKHR must be
  declared as a three-component vector of 32-bit floating-point values

Test Case(s)

Example 1

//dxc ObjectRayDirection_test.hlsl -T lib_6_8 -enable-16bit-types -O0

export float3 fn() {
    return ObjectRayDirection();
}

SPIRV Example(s):

Example 2

//dxc ObjectRayDirection_spirv_test.hlsl -T lib_6_8 -E fn -enable-16bit-types -spirv -fspv-target-env=universal1.5 -fcgl -O0

[shader("intersection")]
void fn() {
float3 	ret = ObjectRayDirection();
}

HLSL:

The object-space direction for the current ray. Object-space refers to the space of the current bottom-level acceleration structure.

Syntax

float3 ObjectRayDirection();

Remarks

This function can be called from the following raytracing shader types:

• Any Hit Shader
• Closest Hit Shader
• Intersection Shader

See also

Direct3D 12 Raytracing HLSL Reference