Reimplement Vulkan shader objects. (#1764)

* Reimplement Vulkan shader objects.

This change reimplements Vulkan shader objects in the `gfx` layer so that it is no longer layered on top of the `DescriptorSet` abstraction. Since this is the last implementation that uses `DescriptorSet`, the change also removes all `DescriptorSet` related API from public `gfx` interface.

The Vulkan implementation now passes all test cases, but it still have two issues:
1. The PushConstant setting is not correct, this is because we don't seem to be able to get correct reflection data about the size of push constants for an entry-point.
2. The `shader-toy` example can't run on Vulkan, because it currently sets nullptr to `Texture` bindings, and this change doesn't properly handle setting resource to null in `ShaderObject`s yet. If we can use the `nullDescriptor` feature on vulkan, this implementation will be simple. However we still want to decide whether we want to use a Vulkan 1.2 feature for this.

* Fix up

2 files changed, 1 insertions, 46 deletions

diff --git a/tools/render-test/slang-support.cpp b/tools/render-test/slang-support.cpp
index c6d2b971e..72732363e 100644
--- a/tools/render-test/slang-support.cpp
+++ b/tools/render-test/slang-support.cpp
@@ -52,16 +52,10 @@ gfx::StageType translateStage(SlangStage slangStage)
 
 void ShaderCompilerUtil::Output::set(
     PipelineType                        pipelineType,
-    const IShaderProgram::KernelDesc*   inKernelDescs,
-    Slang::Index                        kernelDescCount,
     slang::IComponentType*              inSlangProgram)
 {
-    kernelDescs.clear();
-    kernelDescs.addRange(inKernelDescs, kernelDescCount);
     slangProgram = inSlangProgram;
     desc.pipelineType = pipelineType;
-    desc.kernels = kernelDescs.getBuffer();
-    desc.kernelCount = kernelDescCount;
     desc.slangProgram = inSlangProgram;
 }
 
@@ -70,11 +64,8 @@ void ShaderCompilerUtil::Output::reset()
     {
         desc.pipelineType = PipelineType::Unknown;
         desc.slangProgram = nullptr;
-        desc.kernels = nullptr;
-        desc.kernelCount = 0;
     }
 
-    kernelDescs.clear();
     if (m_requestForKernels && session)
     {
         spDestroyCompileRequest(m_requestForKernels);
@@ -245,28 +236,7 @@ void ShaderCompilerUtil::Output::reset()
         actualEntryPoints = request.entryPoints;
     }
 
-    Slang::List<IShaderProgram::KernelDesc> kernelDescs;
-
-    Index actualEntryPointCount = actualEntryPoints.getCount();
-    for(Index ee = 0; ee < actualEntryPointCount; ++ee)
-    {
-        auto& actualEntryPoint = actualEntryPoints[ee];
-
-        size_t codeSize = 0;
-        char const* code = (char const*) spGetEntryPointCode(slangRequest, int(ee), &codeSize);
-
-        auto gfxStage = translateStage(actualEntryPoint.slangStage);
-
-        IShaderProgram::KernelDesc kernelDesc;
-        kernelDesc.stage = gfxStage;
-        kernelDesc.codeBegin = code;
-        kernelDesc.codeEnd = code + codeSize;
-        kernelDesc.entryPointName = actualEntryPoint.name;
-
-        kernelDescs.add(kernelDesc);
-    }
-
-    out.set(input.pipelineType, kernelDescs.getBuffer(), kernelDescs.getCount(), linkedSlangProgram);
+    out.set(input.pipelineType, linkedSlangProgram);
 
     return SLANG_OK;
 }
diff --git a/tools/render-test/slang-support.h b/tools/render-test/slang-support.h
index 6fa850874..7e00a2c72 100644
--- a/tools/render-test/slang-support.h
+++ b/tools/render-test/slang-support.h
@@ -60,8 +60,6 @@ struct ShaderCompilerUtil
     {
         void set(
             PipelineType                        pipelineType,
-            const IShaderProgram::KernelDesc*   kernelDescs,
-            Slang::Index                        kernelDescCount,
             slang::IComponentType*              slangProgram);
         void reset();
         ~Output()
@@ -69,19 +67,6 @@ struct ShaderCompilerUtil
             reset();
         }
 
-        Slang::Index findKernelDescIndex(gfx::StageType stage) const
-        {
-            for (Slang::Index i = 0; i < kernelDescs.getCount(); ++i)
-            {
-                if (kernelDescs[i].stage == stage)
-                {
-                    return i;
-                }
-            }
-            return -1;
-        }
-
-        Slang::List<IShaderProgram::KernelDesc> kernelDescs;
         ComPtr<slang::IComponentType> slangProgram;
         IShaderProgram::Desc desc = {};