Fix D3D12 descriptor set staging for shader tables

engine/src/RHI/D3D12/D3D12CommandList.cpp

@@ -348,10 +348,12 @@ void D3D12CommandList::SetGraphicsDescriptorSets(
         }
 
         D3D12DescriptorHeap* heap = d3d12Set->GetHeap();
-        if (heap == nullptr || !heap->IsShaderVisible()) {
+        if (heap == nullptr) {
             continue;
         }
 
+        // Descriptor sets are staged in CPU-visible heaps and copied into this
+        // command list's shader-visible heaps immediately before binding.
         if (heap->GetType() == DescriptorHeapType::CBV_SRV_UAV) {
             const bool hasSrvTable = d3d12Layout->UsesSetLayouts()
                 ? d3d12Layout->HasShaderResourceTable(setIndex)
@@ -581,10 +583,12 @@ void D3D12CommandList::SetComputeDescriptorSets(
         }
 
         D3D12DescriptorHeap* heap = d3d12Set->GetHeap();
-        if (heap == nullptr || !heap->IsShaderVisible()) {
+        if (heap == nullptr) {
             continue;
         }
 
+        // Descriptor sets are staged in CPU-visible heaps and copied into this
+        // command list's shader-visible heaps immediately before binding.
         if (heap->GetType() == DescriptorHeapType::CBV_SRV_UAV) {
             const bool hasSrvTable = d3d12Layout->UsesSetLayouts()
                 ? d3d12Layout->HasShaderResourceTable(setIndex)

engine/src/RHI/D3D12/D3D12DescriptorHeap.cpp

@@ -77,6 +77,9 @@ D3D12_CPU_DESCRIPTOR_HANDLE D3D12DescriptorHeap::GetCPUDescriptorHandleForHeapSt
 }
 
 D3D12_GPU_DESCRIPTOR_HANDLE D3D12DescriptorHeap::GetGPUDescriptorHandleForHeapStart() const {
+    if (!m_shaderVisible || m_descriptorHeap == nullptr) {
+        return D3D12_GPU_DESCRIPTOR_HANDLE{0};
+    }
     return m_descriptorHeap->GetGPUDescriptorHandleForHeapStart();
 }
 
@@ -89,6 +92,10 @@ CPUDescriptorHandle D3D12DescriptorHeap::GetCPUDescriptorHandle(uint32_t index)
 }
 
 GPUDescriptorHandle D3D12DescriptorHeap::GetGPUDescriptorHandle(uint32_t index) {
+    if (!m_shaderVisible || m_descriptorHeap == nullptr) {
+        return GPUDescriptorHandle{0};
+    }
+
     D3D12_GPU_DESCRIPTOR_HANDLE handle = m_descriptorHeap->GetGPUDescriptorHandleForHeapStart();
     handle.ptr += index * m_descriptorSize;
     GPUDescriptorHandle result;

engine/src/RHI/D3D12/D3D12Device.cpp

@@ -51,6 +51,10 @@ bool HasShaderPayload(const ShaderCompileDesc& desc) {
     return !desc.source.empty() || !desc.fileName.empty() || !desc.compiledBinary.empty();
 }
 
+bool UsesTransientShaderVisibleDescriptorHeap(DescriptorHeapType type) {
+    return type == DescriptorHeapType::CBV_SRV_UAV || type == DescriptorHeapType::Sampler;
+}
+
 bool ShouldTraceVolumetricShaderCompile(const ShaderCompileDesc& desc) {
     const std::string fileName = NarrowAscii(desc.fileName);
     if (fileName.find("volumetric") != std::string::npos) {
@@ -1279,6 +1283,11 @@ RHIDescriptorPool* D3D12Device::CreateDescriptorPool(const DescriptorPoolDesc& d
     auto* pool = new D3D12DescriptorHeap();
     DescriptorPoolDesc poolDesc = desc;
     poolDesc.device = m_device.Get();
+    if (UsesTransientShaderVisibleDescriptorHeap(poolDesc.type)) {
+        // Descriptor sets are staged in CPU-visible heaps and copied into the
+        // command list's transient shader-visible heaps before each bind.
+        poolDesc.shaderVisible = false;
+    }
     if (pool->Initialize(poolDesc)) {
         return pool;
     }

tests/RHI/D3D12/unit/test_backend_specific.cpp

@@ -1,5 +1,6 @@
 #include "fixtures/D3D12TestFixture.h"
 
+#include "XCEngine/RHI/D3D12/D3D12DescriptorHeap.h"
 #include "XCEngine/RHI/D3D12/D3D12DescriptorSet.h"
 #include "XCEngine/RHI/D3D12/D3D12PipelineLayout.h"
 #include "XCEngine/RHI/RHIDescriptorPool.h"
@@ -54,6 +55,64 @@ TEST_F(D3D12TestFixture, DescriptorSet_MixedBindings_AssignDescriptorIndicesByTy
     delete pool;
 }
 
+TEST_F(D3D12TestFixture, DescriptorSet_TableBindingsUseCpuVisibleStagingHeaps) {
+    DescriptorPoolDesc texturePoolDesc = {};
+    texturePoolDesc.type = DescriptorHeapType::CBV_SRV_UAV;
+    texturePoolDesc.descriptorCount = 2;
+    texturePoolDesc.shaderVisible = true;
+
+    RHIDescriptorPool* texturePool = GetDevice()->CreateDescriptorPool(texturePoolDesc);
+    ASSERT_NE(texturePool, nullptr);
+
+    DescriptorSetLayoutBinding textureBinding = {};
+    textureBinding.binding = 0;
+    textureBinding.type = static_cast<uint32_t>(DescriptorType::SRV);
+    textureBinding.count = 1;
+
+    DescriptorSetLayoutDesc textureLayoutDesc = {};
+    textureLayoutDesc.bindings = &textureBinding;
+    textureLayoutDesc.bindingCount = 1;
+
+    RHIDescriptorSet* textureSet = texturePool->AllocateSet(textureLayoutDesc);
+    ASSERT_NE(textureSet, nullptr);
+    auto* textureD3D12Set = static_cast<D3D12DescriptorSet*>(textureSet);
+    ASSERT_NE(textureD3D12Set->GetHeap(), nullptr);
+    EXPECT_FALSE(textureD3D12Set->GetHeap()->IsShaderVisible());
+
+    DescriptorPoolDesc samplerPoolDesc = {};
+    samplerPoolDesc.type = DescriptorHeapType::Sampler;
+    samplerPoolDesc.descriptorCount = 1;
+    samplerPoolDesc.shaderVisible = true;
+
+    RHIDescriptorPool* samplerPool = GetDevice()->CreateDescriptorPool(samplerPoolDesc);
+    ASSERT_NE(samplerPool, nullptr);
+
+    DescriptorSetLayoutBinding samplerBinding = {};
+    samplerBinding.binding = 0;
+    samplerBinding.type = static_cast<uint32_t>(DescriptorType::Sampler);
+    samplerBinding.count = 1;
+
+    DescriptorSetLayoutDesc samplerLayoutDesc = {};
+    samplerLayoutDesc.bindings = &samplerBinding;
+    samplerLayoutDesc.bindingCount = 1;
+
+    RHIDescriptorSet* samplerSet = samplerPool->AllocateSet(samplerLayoutDesc);
+    ASSERT_NE(samplerSet, nullptr);
+    auto* samplerD3D12Set = static_cast<D3D12DescriptorSet*>(samplerSet);
+    ASSERT_NE(samplerD3D12Set->GetHeap(), nullptr);
+    EXPECT_FALSE(samplerD3D12Set->GetHeap()->IsShaderVisible());
+
+    textureSet->Shutdown();
+    delete textureSet;
+    texturePool->Shutdown();
+    delete texturePool;
+
+    samplerSet->Shutdown();
+    delete samplerSet;
+    samplerPool->Shutdown();
+    delete samplerPool;
+}
+
 TEST_F(D3D12TestFixture, DescriptorSet_MultipleConstantBuffersUploadIndependently) {
     DescriptorPoolDesc poolDesc = {};
     poolDesc.type = DescriptorHeapType::CBV_SRV_UAV;