Implement texture functions for Metal target (#4158)

* Impl texture APIs for Metal target

This commit is to implement texture functions for Metal target.

The following functions are implemented and tested.
 - GetDimensions()
 - CalculateLevelOfDetail()
 - CalculateLevelOfDetailUnclamped()
 - Sample()
 - SampleBias()
 - SampleLevel()
 - SampleCmp()
 - SampleCmpLevelZero()
 - Gather()
 - SampleGrad()
 - Load()

Metal has limited support for the texture functions compared to HLSL.
 - LOD is not supported for 1D texture,
 - Depth textures are limited to 2D, 2DArray, Cube and CubeArray
   textures.
 - "Offset" variants are limited to 2D, 2DArray, 2D-Depth,
   2DArray-Depth and 3D textures.

The functions that cannot be implemented for Metal should properly
be handled by the capability system later.

* Fix the failing test, multi-file.hlsl

I am not sure why this change is needed.

* Fix compile errors on macOS 2nd try

* Remove a typo character to fix the compile error

* Trivial clean up

* Remove `as_type` where it was intended as static_cast

* Use a simpler sytax for __intrinsic_asm

* Trivial clean up

* Remove TEST_AFTER_FIXING_CAPABILITY_PROBLEM after fixing normalize

* Fix the failing test properly

* Fix an incorrect setup of Depth-cube texture

---------

Co-authored-by: Yong He <yonghe@outlook.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/source/slang/slang-capabilities.capdef b/source/slang/slang-capabilities.capdef
index 4d4fc7ccf..5c672d398 100644
--- a/source/slang/slang-capabilities.capdef
+++ b/source/slang/slang-capabilities.capdef
@@ -62,9 +62,9 @@ def spirv_1_6 : spirv_1_5;
 alias spirv = spirv_1_0;
 alias spirv_latest = spirv_1_6;
 
-alias any_target = hlsl | glsl | c | cpp | cuda | spirv;
-alias any_textual_target = hlsl | glsl | c | cpp | cuda;
-alias any_gfx_target = hlsl | glsl | spirv;
+alias any_target = hlsl | metal | glsl | c | cpp | cuda | spirv;
+alias any_textual_target = hlsl | metal | glsl | c | cpp | cuda;
+alias any_gfx_target = hlsl | metal | glsl | spirv;
 alias any_cpp_target = cpp | cuda;
 
 alias cpp_cuda = cpp | cuda;
@@ -75,6 +75,7 @@ alias cpp_cuda_glsl_hlsl_metal_spirv = cpp | cuda | glsl | hlsl | metal | spirv_
 alias cpp_cuda_hlsl = cpp | cuda | hlsl;
 alias cpp_glsl = cpp | glsl;
 alias cpp_glsl_hlsl_spirv = cpp | glsl | hlsl | spirv_1_0;
+alias cpp_glsl_hlsl_metal_spirv = cpp | glsl | hlsl | metal | spirv_1_0;
 alias cpp_hlsl = cpp | hlsl;
 alias cuda_glsl_hlsl = cuda | glsl | hlsl;
 alias cuda_glsl_hlsl_spirv = cuda | glsl | hlsl | spirv_1_0;
@@ -84,6 +85,7 @@ alias cuda_hlsl = cuda | hlsl;
 alias cuda_hlsl_spirv = cuda | hlsl | spirv;
 alias glsl_hlsl_spirv = glsl | hlsl | spirv;
 alias glsl_hlsl_metal_spirv = glsl | hlsl | metal | spirv;
+alias glsl_metal_spirv = glsl | metal | spirv;
 alias glsl_spirv = glsl | spirv;
 alias hlsl_spirv = hlsl | spirv;