fix(rhi): honor firstSet in set-aware d3d12 bindings

engine/include/XCEngine/RHI/D3D12/D3D12PipelineLayout.h

@@ -17,6 +17,13 @@ class D3D12Device;
 
 class D3D12PipelineLayout : public RHIPipelineLayout {
 public:
+    struct SetRootParameterMapping {
+        std::unordered_map<uint32_t, uint32_t> constantBufferRootIndices;
+        uint32_t shaderResourceTableRootIndex = UINT32_MAX;
+        uint32_t unorderedAccessTableRootIndex = UINT32_MAX;
+        uint32_t samplerTableRootIndex = UINT32_MAX;
+    };
+
     D3D12PipelineLayout();
     ~D3D12PipelineLayout() override;
 
@@ -27,6 +34,9 @@ public:
     void* GetNativeHandle() override { return m_rootSignature.Get(); }
     ID3D12RootSignature* GetRootSignature() const { return m_rootSignature.Get(); }
 
+    bool UsesSetLayouts() const { return m_desc.setLayoutCount > 0 && m_desc.setLayouts != nullptr; }
+    uint32_t GetSetLayoutCount() const { return m_desc.setLayoutCount; }
+
     bool HasConstantBufferBinding(uint32_t binding) const;
     uint32_t GetConstantBufferRootParameterIndex(uint32_t binding) const;
     bool HasShaderResourceTable() const;
@@ -35,10 +45,21 @@ public:
     uint32_t GetUnorderedAccessTableRootParameterIndex() const;
     bool HasSamplerTable() const;
     uint32_t GetSamplerTableRootParameterIndex() const;
+
+    bool HasConstantBufferBinding(uint32_t setIndex, uint32_t binding) const;
+    uint32_t GetConstantBufferRootParameterIndex(uint32_t setIndex, uint32_t binding) const;
+    bool HasShaderResourceTable(uint32_t setIndex) const;
+    uint32_t GetShaderResourceTableRootParameterIndex(uint32_t setIndex) const;
+    bool HasUnorderedAccessTable(uint32_t setIndex) const;
+    uint32_t GetUnorderedAccessTableRootParameterIndex(uint32_t setIndex) const;
+    bool HasSamplerTable(uint32_t setIndex) const;
+    uint32_t GetSamplerTableRootParameterIndex(uint32_t setIndex) const;
     const RHIPipelineLayoutDesc& GetDesc() const { return m_desc; }
 
 private:
     bool InitializeInternal(D3D12Device* device, const RHIPipelineLayoutDesc& desc);
+    bool InitializeSetAwareRootSignature();
+    bool InitializeFlatRootSignature();
 
     ComPtr<ID3D12RootSignature> m_rootSignature;
     D3D12Device* m_device;
@@ -47,6 +68,7 @@ private:
     uint32_t m_shaderResourceTableRootIndex = UINT32_MAX;
     uint32_t m_unorderedAccessTableRootIndex = UINT32_MAX;
     uint32_t m_samplerTableRootIndex = UINT32_MAX;
+    std::vector<SetRootParameterMapping> m_setRootParameterMappings;
     std::vector<DescriptorSetLayoutDesc> m_setLayouts;
     std::vector<std::vector<DescriptorSetLayoutBinding>> m_setLayoutBindings;
     std::vector<D3D12_ROOT_PARAMETER> m_rootParameters;

engine/src/RHI/D3D12/D3D12CommandList.cpp

@@ -197,15 +197,23 @@ void D3D12CommandList::SetGraphicsDescriptorSets(
             continue;
         }
 
+        const uint32_t setIndex = firstSet + i;
         D3D12DescriptorSet* d3d12Set = static_cast<D3D12DescriptorSet*>(descriptorSets[i]);
         const DescriptorSetLayoutBinding* bindings = d3d12Set->GetBindings();
         for (uint32_t bindingIndex = 0; bindingIndex < d3d12Set->GetBindingCount(); ++bindingIndex) {
             const DescriptorSetLayoutBinding& binding = bindings[bindingIndex];
+            const bool hasBinding = d3d12Layout->UsesSetLayouts()
+                ? d3d12Layout->HasConstantBufferBinding(setIndex, binding.binding)
+                : d3d12Layout->HasConstantBufferBinding(binding.binding);
+            const uint32_t rootParameterIndex = d3d12Layout->UsesSetLayouts()
+                ? d3d12Layout->GetConstantBufferRootParameterIndex(setIndex, binding.binding)
+                : d3d12Layout->GetConstantBufferRootParameterIndex(binding.binding);
+
             if (static_cast<DescriptorType>(binding.type) == DescriptorType::CBV &&
-                d3d12Layout->HasConstantBufferBinding(binding.binding) &&
+                hasBinding &&
                 d3d12Set->UploadConstantBuffer(binding.binding)) {
                 SetGraphicsRootConstantBufferView(
-                    d3d12Layout->GetConstantBufferRootParameterIndex(binding.binding),
+                    rootParameterIndex,
                     d3d12Set->GetConstantBufferGPUAddress(binding.binding));
             }
         }
@@ -216,28 +224,49 @@ void D3D12CommandList::SetGraphicsDescriptorSets(
         }
 
         if (heap->GetType() == DescriptorHeapType::CBV_SRV_UAV) {
-            if (d3d12Set->HasBindingType(DescriptorType::SRV) && d3d12Layout->HasShaderResourceTable()) {
+            const bool hasSrvTable = d3d12Layout->UsesSetLayouts()
+                ? d3d12Layout->HasShaderResourceTable(setIndex)
+                : d3d12Layout->HasShaderResourceTable();
+            const bool hasUavTable = d3d12Layout->UsesSetLayouts()
+                ? d3d12Layout->HasUnorderedAccessTable(setIndex)
+                : d3d12Layout->HasUnorderedAccessTable();
+
+            if (d3d12Set->HasBindingType(DescriptorType::SRV) && hasSrvTable) {
                 const uint32_t srvBinding = d3d12Set->GetFirstBindingOfType(DescriptorType::SRV);
                 const D3D12_GPU_DESCRIPTOR_HANDLE gpuHandle = d3d12Set->GetGPUHandleForBinding(srvBinding);
                 if (gpuHandle.ptr != 0) {
-                    SetGraphicsRootDescriptorTable(d3d12Layout->GetShaderResourceTableRootParameterIndex(), gpuHandle);
+                    SetGraphicsRootDescriptorTable(
+                        d3d12Layout->UsesSetLayouts()
+                            ? d3d12Layout->GetShaderResourceTableRootParameterIndex(setIndex)
+                            : d3d12Layout->GetShaderResourceTableRootParameterIndex(),
+                        gpuHandle);
                 }
             }
 
-            if (d3d12Set->HasBindingType(DescriptorType::UAV) && d3d12Layout->HasUnorderedAccessTable()) {
+            if (d3d12Set->HasBindingType(DescriptorType::UAV) && hasUavTable) {
                 const uint32_t uavBinding = d3d12Set->GetFirstBindingOfType(DescriptorType::UAV);
                 const D3D12_GPU_DESCRIPTOR_HANDLE gpuHandle = d3d12Set->GetGPUHandleForBinding(uavBinding);
                 if (gpuHandle.ptr != 0) {
-                    SetGraphicsRootDescriptorTable(d3d12Layout->GetUnorderedAccessTableRootParameterIndex(), gpuHandle);
+                    SetGraphicsRootDescriptorTable(
+                        d3d12Layout->UsesSetLayouts()
+                            ? d3d12Layout->GetUnorderedAccessTableRootParameterIndex(setIndex)
+                            : d3d12Layout->GetUnorderedAccessTableRootParameterIndex(),
+                        gpuHandle);
                 }
             }
         } else if (heap->GetType() == DescriptorHeapType::Sampler &&
                    HasSamplerBindings(d3d12Set) &&
-                   d3d12Layout->HasSamplerTable()) {
+                   (d3d12Layout->UsesSetLayouts()
+                        ? d3d12Layout->HasSamplerTable(setIndex)
+                        : d3d12Layout->HasSamplerTable())) {
             const uint32_t samplerBinding = d3d12Set->GetFirstBindingOfType(DescriptorType::Sampler);
             const D3D12_GPU_DESCRIPTOR_HANDLE gpuHandle = d3d12Set->GetGPUHandleForBinding(samplerBinding);
             if (gpuHandle.ptr != 0) {
-                SetGraphicsRootDescriptorTable(d3d12Layout->GetSamplerTableRootParameterIndex(), gpuHandle);
+                SetGraphicsRootDescriptorTable(
+                    d3d12Layout->UsesSetLayouts()
+                        ? d3d12Layout->GetSamplerTableRootParameterIndex(setIndex)
+                        : d3d12Layout->GetSamplerTableRootParameterIndex(),
+                    gpuHandle);
             }
         }
     }
@@ -285,15 +314,23 @@ void D3D12CommandList::SetComputeDescriptorSets(
             continue;
         }
 
+        const uint32_t setIndex = firstSet + i;
         D3D12DescriptorSet* d3d12Set = static_cast<D3D12DescriptorSet*>(descriptorSets[i]);
         const DescriptorSetLayoutBinding* bindings = d3d12Set->GetBindings();
         for (uint32_t bindingIndex = 0; bindingIndex < d3d12Set->GetBindingCount(); ++bindingIndex) {
             const DescriptorSetLayoutBinding& binding = bindings[bindingIndex];
+            const bool hasBinding = d3d12Layout->UsesSetLayouts()
+                ? d3d12Layout->HasConstantBufferBinding(setIndex, binding.binding)
+                : d3d12Layout->HasConstantBufferBinding(binding.binding);
+            const uint32_t rootParameterIndex = d3d12Layout->UsesSetLayouts()
+                ? d3d12Layout->GetConstantBufferRootParameterIndex(setIndex, binding.binding)
+                : d3d12Layout->GetConstantBufferRootParameterIndex(binding.binding);
+
             if (static_cast<DescriptorType>(binding.type) == DescriptorType::CBV &&
-                d3d12Layout->HasConstantBufferBinding(binding.binding) &&
+                hasBinding &&
                 d3d12Set->UploadConstantBuffer(binding.binding)) {
                 m_commandList->SetComputeRootConstantBufferView(
-                    d3d12Layout->GetConstantBufferRootParameterIndex(binding.binding),
+                    rootParameterIndex,
                     d3d12Set->GetConstantBufferGPUAddress(binding.binding));
             }
         }
@@ -304,33 +341,48 @@ void D3D12CommandList::SetComputeDescriptorSets(
         }
 
         if (heap->GetType() == DescriptorHeapType::CBV_SRV_UAV) {
-            if (d3d12Set->HasBindingType(DescriptorType::SRV) && d3d12Layout->HasShaderResourceTable()) {
+            const bool hasSrvTable = d3d12Layout->UsesSetLayouts()
+                ? d3d12Layout->HasShaderResourceTable(setIndex)
+                : d3d12Layout->HasShaderResourceTable();
+            const bool hasUavTable = d3d12Layout->UsesSetLayouts()
+                ? d3d12Layout->HasUnorderedAccessTable(setIndex)
+                : d3d12Layout->HasUnorderedAccessTable();
+
+            if (d3d12Set->HasBindingType(DescriptorType::SRV) && hasSrvTable) {
                 const uint32_t srvBinding = d3d12Set->GetFirstBindingOfType(DescriptorType::SRV);
                 const D3D12_GPU_DESCRIPTOR_HANDLE gpuHandle = d3d12Set->GetGPUHandleForBinding(srvBinding);
                 if (gpuHandle.ptr != 0) {
                     m_commandList->SetComputeRootDescriptorTable(
-                        d3d12Layout->GetShaderResourceTableRootParameterIndex(),
+                        d3d12Layout->UsesSetLayouts()
+                            ? d3d12Layout->GetShaderResourceTableRootParameterIndex(setIndex)
+                            : d3d12Layout->GetShaderResourceTableRootParameterIndex(),
                         gpuHandle);
                 }
             }
 
-            if (d3d12Set->HasBindingType(DescriptorType::UAV) && d3d12Layout->HasUnorderedAccessTable()) {
+            if (d3d12Set->HasBindingType(DescriptorType::UAV) && hasUavTable) {
                 const uint32_t uavBinding = d3d12Set->GetFirstBindingOfType(DescriptorType::UAV);
                 const D3D12_GPU_DESCRIPTOR_HANDLE gpuHandle = d3d12Set->GetGPUHandleForBinding(uavBinding);
                 if (gpuHandle.ptr != 0) {
                     m_commandList->SetComputeRootDescriptorTable(
-                        d3d12Layout->GetUnorderedAccessTableRootParameterIndex(),
+                        d3d12Layout->UsesSetLayouts()
+                            ? d3d12Layout->GetUnorderedAccessTableRootParameterIndex(setIndex)
+                            : d3d12Layout->GetUnorderedAccessTableRootParameterIndex(),
                         gpuHandle);
                 }
             }
         } else if (heap->GetType() == DescriptorHeapType::Sampler &&
                    HasSamplerBindings(d3d12Set) &&
-                   d3d12Layout->HasSamplerTable()) {
+                   (d3d12Layout->UsesSetLayouts()
+                        ? d3d12Layout->HasSamplerTable(setIndex)
+                        : d3d12Layout->HasSamplerTable())) {
             const uint32_t samplerBinding = d3d12Set->GetFirstBindingOfType(DescriptorType::Sampler);
             const D3D12_GPU_DESCRIPTOR_HANDLE gpuHandle = d3d12Set->GetGPUHandleForBinding(samplerBinding);
             if (gpuHandle.ptr != 0) {
                 m_commandList->SetComputeRootDescriptorTable(
-                    d3d12Layout->GetSamplerTableRootParameterIndex(),
+                    d3d12Layout->UsesSetLayouts()
+                        ? d3d12Layout->GetSamplerTableRootParameterIndex(setIndex)
+                        : d3d12Layout->GetSamplerTableRootParameterIndex(),
                     gpuHandle);
             }
         }

engine/src/RHI/D3D12/D3D12PipelineLayout.cpp

@@ -1,6 +1,8 @@
 #include "XCEngine/RHI/D3D12/D3D12PipelineLayout.h"
 #include "XCEngine/RHI/D3D12/D3D12Device.h"
 
+#include <algorithm>
+
 namespace XCEngine {
 namespace RHI {
 
@@ -28,6 +30,52 @@ void AccumulateDescriptorCounts(const DescriptorSetLayoutDesc& setLayout, RHIPip
     }
 }
 
+uint32_t CountBindingEntriesOfType(const DescriptorSetLayoutDesc& setLayout, DescriptorType type) {
+    uint32_t count = 0;
+    for (uint32_t bindingIndex = 0; bindingIndex < setLayout.bindingCount; ++bindingIndex) {
+        if (static_cast<DescriptorType>(setLayout.bindings[bindingIndex].type) == type) {
+            ++count;
+        }
+    }
+
+    return count;
+}
+
+uint32_t SumDescriptorCountOfType(const DescriptorSetLayoutDesc& setLayout, DescriptorType type) {
+    uint32_t count = 0;
+    for (uint32_t bindingIndex = 0; bindingIndex < setLayout.bindingCount; ++bindingIndex) {
+        const DescriptorSetLayoutBinding& binding = setLayout.bindings[bindingIndex];
+        if (static_cast<DescriptorType>(binding.type) == type) {
+            count += binding.count > 0 ? binding.count : 1u;
+        }
+    }
+
+    return count;
+}
+
+std::vector<const DescriptorSetLayoutBinding*> GatherBindingsOfTypeSorted(
+    const DescriptorSetLayoutDesc& setLayout,
+    DescriptorType type) {
+    std::vector<const DescriptorSetLayoutBinding*> bindings;
+    bindings.reserve(setLayout.bindingCount);
+
+    for (uint32_t bindingIndex = 0; bindingIndex < setLayout.bindingCount; ++bindingIndex) {
+        const DescriptorSetLayoutBinding& binding = setLayout.bindings[bindingIndex];
+        if (static_cast<DescriptorType>(binding.type) == type) {
+            bindings.push_back(&binding);
+        }
+    }
+
+    std::sort(
+        bindings.begin(),
+        bindings.end(),
+        [](const DescriptorSetLayoutBinding* left, const DescriptorSetLayoutBinding* right) {
+            return left->binding < right->binding;
+        });
+
+    return bindings;
+}
+
 } // namespace
 
 D3D12PipelineLayout::D3D12PipelineLayout()
@@ -88,7 +136,315 @@ bool D3D12PipelineLayout::InitializeInternal(D3D12Device* device, const RHIPipel
     m_shaderResourceTableRootIndex = UINT32_MAX;
     m_unorderedAccessTableRootIndex = UINT32_MAX;
     m_samplerTableRootIndex = UINT32_MAX;
+    m_setRootParameterMappings.clear();
 
+    if (UsesSetLayouts()) {
+        if (!InitializeSetAwareRootSignature()) {
+            return false;
+        }
+    } else {
+        if (!InitializeFlatRootSignature()) {
+            return false;
+        }
+    }
+
+    D3D12_ROOT_SIGNATURE_DESC rootSigDesc = D3D12RootSignature::CreateDesc(
+        m_rootParameters.empty() ? nullptr : m_rootParameters.data(),
+        static_cast<uint32_t>(m_rootParameters.size()),
+        nullptr, 0,
+        D3D12_ROOT_SIGNATURE_FLAG_ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT);
+
+    ID3D12Device* d3d12Device = device->GetDevice();
+    if (!d3d12Device) {
+        return false;
+    }
+
+    ID3DBlob* signature = nullptr;
+    ID3DBlob* error = nullptr;
+
+    HRESULT hr = D3D12SerializeRootSignature(&rootSigDesc, D3D_ROOT_SIGNATURE_VERSION_1, &signature, &error);
+    if (FAILED(hr)) {
+        if (error) {
+            error->Release();
+        }
+        return false;
+    }
+
+    hr = d3d12Device->CreateRootSignature(0, signature->GetBufferPointer(), signature->GetBufferSize(), IID_PPV_ARGS(&m_rootSignature));
+    signature->Release();
+
+    if (FAILED(hr)) {
+        return false;
+    }
+
+    return true;
+}
+
+void D3D12PipelineLayout::Shutdown() {
+    m_rootSignature.Reset();
+    m_desc = {};
+    m_rootParameters.clear();
+    m_descriptorRanges.clear();
+    m_constantBufferRootIndices.clear();
+    m_shaderResourceTableRootIndex = UINT32_MAX;
+    m_unorderedAccessTableRootIndex = UINT32_MAX;
+    m_samplerTableRootIndex = UINT32_MAX;
+    m_setRootParameterMappings.clear();
+    m_setLayouts.clear();
+    m_setLayoutBindings.clear();
+    m_device = nullptr;
+}
+
+bool D3D12PipelineLayout::HasConstantBufferBinding(uint32_t binding) const {
+    if (UsesSetLayouts()) {
+        return HasConstantBufferBinding(0, binding);
+    }
+
+    return m_constantBufferRootIndices.find(binding) != m_constantBufferRootIndices.end();
+}
+
+uint32_t D3D12PipelineLayout::GetConstantBufferRootParameterIndex(uint32_t binding) const {
+    if (UsesSetLayouts()) {
+        return GetConstantBufferRootParameterIndex(0, binding);
+    }
+
+    auto it = m_constantBufferRootIndices.find(binding);
+    if (it != m_constantBufferRootIndices.end()) {
+        return it->second;
+    }
+    return UINT32_MAX;
+}
+
+bool D3D12PipelineLayout::HasShaderResourceTable() const {
+    if (UsesSetLayouts()) {
+        return HasShaderResourceTable(0);
+    }
+
+    return m_shaderResourceTableRootIndex != UINT32_MAX;
+}
+
+uint32_t D3D12PipelineLayout::GetShaderResourceTableRootParameterIndex() const {
+    if (UsesSetLayouts()) {
+        return GetShaderResourceTableRootParameterIndex(0);
+    }
+
+    return m_shaderResourceTableRootIndex;
+}
+
+bool D3D12PipelineLayout::HasUnorderedAccessTable() const {
+    if (UsesSetLayouts()) {
+        return HasUnorderedAccessTable(0);
+    }
+
+    return m_unorderedAccessTableRootIndex != UINT32_MAX;
+}
+
+uint32_t D3D12PipelineLayout::GetUnorderedAccessTableRootParameterIndex() const {
+    if (UsesSetLayouts()) {
+        return GetUnorderedAccessTableRootParameterIndex(0);
+    }
+
+    return m_unorderedAccessTableRootIndex;
+}
+
+bool D3D12PipelineLayout::HasSamplerTable() const {
+    if (UsesSetLayouts()) {
+        return HasSamplerTable(0);
+    }
+
+    return m_samplerTableRootIndex != UINT32_MAX;
+}
+
+uint32_t D3D12PipelineLayout::GetSamplerTableRootParameterIndex() const {
+    if (UsesSetLayouts()) {
+        return GetSamplerTableRootParameterIndex(0);
+    }
+
+    return m_samplerTableRootIndex;
+}
+
+bool D3D12PipelineLayout::HasConstantBufferBinding(uint32_t setIndex, uint32_t binding) const {
+    if (!UsesSetLayouts()) {
+        return setIndex == 0 && HasConstantBufferBinding(binding);
+    }
+
+    if (setIndex >= m_setRootParameterMappings.size()) {
+        return false;
+    }
+
+    return m_setRootParameterMappings[setIndex].constantBufferRootIndices.find(binding) !=
+           m_setRootParameterMappings[setIndex].constantBufferRootIndices.end();
+}
+
+uint32_t D3D12PipelineLayout::GetConstantBufferRootParameterIndex(uint32_t setIndex, uint32_t binding) const {
+    if (!UsesSetLayouts()) {
+        return setIndex == 0 ? GetConstantBufferRootParameterIndex(binding) : UINT32_MAX;
+    }
+
+    if (setIndex >= m_setRootParameterMappings.size()) {
+        return UINT32_MAX;
+    }
+
+    const auto& rootIndices = m_setRootParameterMappings[setIndex].constantBufferRootIndices;
+    auto it = rootIndices.find(binding);
+    if (it != rootIndices.end()) {
+        return it->second;
+    }
+
+    return UINT32_MAX;
+}
+
+bool D3D12PipelineLayout::HasShaderResourceTable(uint32_t setIndex) const {
+    if (!UsesSetLayouts()) {
+        return setIndex == 0 && HasShaderResourceTable();
+    }
+
+    return setIndex < m_setRootParameterMappings.size() &&
+           m_setRootParameterMappings[setIndex].shaderResourceTableRootIndex != UINT32_MAX;
+}
+
+uint32_t D3D12PipelineLayout::GetShaderResourceTableRootParameterIndex(uint32_t setIndex) const {
+    if (!UsesSetLayouts()) {
+        return setIndex == 0 ? GetShaderResourceTableRootParameterIndex() : UINT32_MAX;
+    }
+
+    return setIndex < m_setRootParameterMappings.size()
+        ? m_setRootParameterMappings[setIndex].shaderResourceTableRootIndex
+        : UINT32_MAX;
+}
+
+bool D3D12PipelineLayout::HasUnorderedAccessTable(uint32_t setIndex) const {
+    if (!UsesSetLayouts()) {
+        return setIndex == 0 && HasUnorderedAccessTable();
+    }
+
+    return setIndex < m_setRootParameterMappings.size() &&
+           m_setRootParameterMappings[setIndex].unorderedAccessTableRootIndex != UINT32_MAX;
+}
+
+uint32_t D3D12PipelineLayout::GetUnorderedAccessTableRootParameterIndex(uint32_t setIndex) const {
+    if (!UsesSetLayouts()) {
+        return setIndex == 0 ? GetUnorderedAccessTableRootParameterIndex() : UINT32_MAX;
+    }
+
+    return setIndex < m_setRootParameterMappings.size()
+        ? m_setRootParameterMappings[setIndex].unorderedAccessTableRootIndex
+        : UINT32_MAX;
+}
+
+bool D3D12PipelineLayout::HasSamplerTable(uint32_t setIndex) const {
+    if (!UsesSetLayouts()) {
+        return setIndex == 0 && HasSamplerTable();
+    }
+
+    return setIndex < m_setRootParameterMappings.size() &&
+           m_setRootParameterMappings[setIndex].samplerTableRootIndex != UINT32_MAX;
+}
+
+uint32_t D3D12PipelineLayout::GetSamplerTableRootParameterIndex(uint32_t setIndex) const {
+    if (!UsesSetLayouts()) {
+        return setIndex == 0 ? GetSamplerTableRootParameterIndex() : UINT32_MAX;
+    }
+
+    return setIndex < m_setRootParameterMappings.size()
+        ? m_setRootParameterMappings[setIndex].samplerTableRootIndex
+        : UINT32_MAX;
+}
+
+bool D3D12PipelineLayout::InitializeSetAwareRootSignature() {
+    const uint32_t setCount = m_desc.setLayoutCount;
+    m_setRootParameterMappings.assign(setCount, SetRootParameterMapping{});
+
+    uint32_t rootParameterCount = 0;
+    uint32_t descriptorRangeCount = 0;
+    for (uint32_t setIndex = 0; setIndex < setCount; ++setIndex) {
+        const DescriptorSetLayoutDesc& setLayout = m_desc.setLayouts[setIndex];
+        rootParameterCount += CountBindingEntriesOfType(setLayout, DescriptorType::CBV);
+        rootParameterCount += SumDescriptorCountOfType(setLayout, DescriptorType::SRV) > 0 ? 1u : 0u;
+        rootParameterCount += SumDescriptorCountOfType(setLayout, DescriptorType::UAV) > 0 ? 1u : 0u;
+        rootParameterCount += SumDescriptorCountOfType(setLayout, DescriptorType::Sampler) > 0 ? 1u : 0u;
+
+        descriptorRangeCount += CountBindingEntriesOfType(setLayout, DescriptorType::SRV);
+        descriptorRangeCount += CountBindingEntriesOfType(setLayout, DescriptorType::UAV);
+        descriptorRangeCount += CountBindingEntriesOfType(setLayout, DescriptorType::Sampler);
+    }
+
+    m_rootParameters.reserve(rootParameterCount);
+    m_descriptorRanges.reserve(descriptorRangeCount);
+
+    uint32_t rootIndex = 0;
+    uint32_t nextCBVRegister = 0;
+    uint32_t nextSRVRegister = 0;
+    uint32_t nextUAVRegister = 0;
+    uint32_t nextSamplerRegister = 0;
+
+    for (uint32_t setIndex = 0; setIndex < setCount; ++setIndex) {
+        const DescriptorSetLayoutDesc& setLayout = m_desc.setLayouts[setIndex];
+        SetRootParameterMapping& setMapping = m_setRootParameterMappings[setIndex];
+
+        const auto cbvBindings = GatherBindingsOfTypeSorted(setLayout, DescriptorType::CBV);
+        for (const DescriptorSetLayoutBinding* binding : cbvBindings) {
+            m_rootParameters.push_back(D3D12RootSignature::CreateCBV(nextCBVRegister, ShaderVisibility::All, 0));
+            setMapping.constantBufferRootIndices[binding->binding] = rootIndex++;
+            nextCBVRegister += binding->count > 0 ? binding->count : 1u;
+        }
+
+        const auto appendDescriptorTable =
+            [this, &rootIndex](
+                const DescriptorSetLayoutDesc& layout,
+                DescriptorType type,
+                D3D12_DESCRIPTOR_RANGE_TYPE rangeType,
+                uint32_t& nextRegister,
+                uint32_t& rootParameterIndex) {
+                const auto bindings = GatherBindingsOfTypeSorted(layout, type);
+                if (bindings.empty()) {
+                    return;
+                }
+
+                const size_t rangeStart = m_descriptorRanges.size();
+                for (const DescriptorSetLayoutBinding* binding : bindings) {
+                    const uint32_t descriptorCount = binding->count > 0 ? binding->count : 1u;
+                    m_descriptorRanges.push_back(
+                        D3D12RootSignature::CreateDescriptorRange(
+                            rangeType,
+                            nextRegister,
+                            descriptorCount,
+                            0));
+                    nextRegister += descriptorCount;
+                }
+
+                m_rootParameters.push_back(
+                    D3D12RootSignature::CreateDescriptorTable(
+                        static_cast<uint32_t>(bindings.size()),
+                        m_descriptorRanges.data() + rangeStart,
+                        ShaderVisibility::All));
+                rootParameterIndex = rootIndex++;
+            };
+
+        appendDescriptorTable(
+            setLayout,
+            DescriptorType::SRV,
+            D3D12_DESCRIPTOR_RANGE_TYPE_SRV,
+            nextSRVRegister,
+            setMapping.shaderResourceTableRootIndex);
+        appendDescriptorTable(
+            setLayout,
+            DescriptorType::UAV,
+            D3D12_DESCRIPTOR_RANGE_TYPE_UAV,
+            nextUAVRegister,
+            setMapping.unorderedAccessTableRootIndex);
+        appendDescriptorTable(
+            setLayout,
+            DescriptorType::Sampler,
+            D3D12_DESCRIPTOR_RANGE_TYPE_SAMPLER,
+            nextSamplerRegister,
+            setMapping.samplerTableRootIndex);
+    }
+
+    return true;
+}
+
+bool D3D12PipelineLayout::InitializeFlatRootSignature() {
     const RHIPipelineLayoutDesc& normalizedDesc = m_desc;
 
     const uint32_t rootParameterCount =
@@ -143,87 +499,8 @@ bool D3D12PipelineLayout::InitializeInternal(D3D12Device* device, const RHIPipel
         rootIndex++;
     }
 
-    D3D12_ROOT_SIGNATURE_DESC rootSigDesc = D3D12RootSignature::CreateDesc(
-        m_rootParameters.empty() ? nullptr : m_rootParameters.data(),
-        static_cast<uint32_t>(m_rootParameters.size()),
-        nullptr, 0,
-        D3D12_ROOT_SIGNATURE_FLAG_ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT);
-
-    ID3D12Device* d3d12Device = device->GetDevice();
-    if (!d3d12Device) {
-        return false;
-    }
-
-    ID3DBlob* signature = nullptr;
-    ID3DBlob* error = nullptr;
-
-    HRESULT hr = D3D12SerializeRootSignature(&rootSigDesc, D3D_ROOT_SIGNATURE_VERSION_1, &signature, &error);
-    if (FAILED(hr)) {
-        if (error) {
-            error->Release();
-        }
-        return false;
-    }
-
-    hr = d3d12Device->CreateRootSignature(0, signature->GetBufferPointer(), signature->GetBufferSize(), IID_PPV_ARGS(&m_rootSignature));
-    signature->Release();
-
-    if (FAILED(hr)) {
-        return false;
-    }
-
     return true;
 }
 
-void D3D12PipelineLayout::Shutdown() {
-    m_rootSignature.Reset();
-    m_desc = {};
-    m_rootParameters.clear();
-    m_descriptorRanges.clear();
-    m_constantBufferRootIndices.clear();
-    m_shaderResourceTableRootIndex = UINT32_MAX;
-    m_unorderedAccessTableRootIndex = UINT32_MAX;
-    m_samplerTableRootIndex = UINT32_MAX;
-    m_setLayouts.clear();
-    m_setLayoutBindings.clear();
-    m_device = nullptr;
-}
-
-bool D3D12PipelineLayout::HasConstantBufferBinding(uint32_t binding) const {
-    return m_constantBufferRootIndices.find(binding) != m_constantBufferRootIndices.end();
-}
-
-uint32_t D3D12PipelineLayout::GetConstantBufferRootParameterIndex(uint32_t binding) const {
-    auto it = m_constantBufferRootIndices.find(binding);
-    if (it != m_constantBufferRootIndices.end()) {
-        return it->second;
-    }
-    return UINT32_MAX;
-}
-
-bool D3D12PipelineLayout::HasShaderResourceTable() const {
-    return m_shaderResourceTableRootIndex != UINT32_MAX;
-}
-
-uint32_t D3D12PipelineLayout::GetShaderResourceTableRootParameterIndex() const {
-    return m_shaderResourceTableRootIndex;
-}
-
-bool D3D12PipelineLayout::HasUnorderedAccessTable() const {
-    return m_unorderedAccessTableRootIndex != UINT32_MAX;
-}
-
-uint32_t D3D12PipelineLayout::GetUnorderedAccessTableRootParameterIndex() const {
-    return m_unorderedAccessTableRootIndex;
-}
-
-bool D3D12PipelineLayout::HasSamplerTable() const {
-    return m_samplerTableRootIndex != UINT32_MAX;
-}
-
-uint32_t D3D12PipelineLayout::GetSamplerTableRootParameterIndex() const {
-    return m_samplerTableRootIndex;
-}
-
 } // namespace RHI
 } // namespace XCEngine

tests/RHI/integration/sphere/main.cpp

@@ -44,6 +44,8 @@ struct MatrixBufferData {
 constexpr float kSphereRadius = 1.0f;
 constexpr int kSphereSegments = 32;
 constexpr float kPi = 3.14159265358979323846f;
+constexpr uint32_t kSphereDescriptorFirstSet = 1;
+constexpr uint32_t kSphereDescriptorSetCount = 4;
 
 std::filesystem::path GetExecutableDirectory() {
     char exePath[MAX_PATH] = {};
@@ -452,10 +454,15 @@ void SphereTest::InitializeSphereResources() {
     ASSERT_NE(mSamplerSet, nullptr);
     mSamplerSet->UpdateSampler(0, mSampler);
 
+    DescriptorSetLayoutDesc setLayouts[kSphereDescriptorSetCount] = {};
+    // Reserve set0 so the integration test exercises non-zero firstSet binding.
+    setLayouts[1] = constantLayoutDesc;
+    setLayouts[2] = textureLayoutDesc;
+    setLayouts[3] = samplerLayoutDesc;
+
     RHIPipelineLayoutDesc pipelineLayoutDesc = {};
-    pipelineLayoutDesc.constantBufferCount = 1;
+    pipelineLayoutDesc.setLayouts = setLayouts;
-    pipelineLayoutDesc.textureCount = 1;
+    pipelineLayoutDesc.setLayoutCount = kSphereDescriptorSetCount;
-    pipelineLayoutDesc.samplerCount = 1;
     mPipelineLayout = GetDevice()->CreatePipelineLayout(pipelineLayoutDesc);
     ASSERT_NE(mPipelineLayout, nullptr);
 
@@ -584,7 +591,7 @@ void SphereTest::RenderFrame() {
 
     cmdList->SetPipelineState(mPipelineState);
     RHIDescriptorSet* descriptorSets[] = { mConstantSet, mTextureSet, mSamplerSet };
-    cmdList->SetGraphicsDescriptorSets(0, 3, descriptorSets, mPipelineLayout);
+    cmdList->SetGraphicsDescriptorSets(kSphereDescriptorFirstSet, 3, descriptorSets, mPipelineLayout);
     cmdList->SetPrimitiveTopology(PrimitiveTopology::TriangleList);
 
     RHIResourceView* vertexBuffers[] = { mVertexBufferView };

tests/RHI/unit/test_pipeline_layout.cpp

@@ -283,10 +283,12 @@ TEST_P(RHITestFixture, PipelineLayout_D3D12InfersBindingClassesFromSetLayouts) {
     ASSERT_NE(layout, nullptr);
 
     auto* d3d12Layout = static_cast<D3D12PipelineLayout*>(layout);
-    EXPECT_TRUE(d3d12Layout->HasConstantBufferBinding(0));
+    EXPECT_TRUE(d3d12Layout->UsesSetLayouts());
-    EXPECT_TRUE(d3d12Layout->HasShaderResourceTable());
+    EXPECT_EQ(d3d12Layout->GetSetLayoutCount(), 4u);
-    EXPECT_TRUE(d3d12Layout->HasUnorderedAccessTable());
+    EXPECT_TRUE(d3d12Layout->HasConstantBufferBinding(0, 0));
-    EXPECT_TRUE(d3d12Layout->HasSamplerTable());
+    EXPECT_TRUE(d3d12Layout->HasShaderResourceTable(1));
+    EXPECT_TRUE(d3d12Layout->HasUnorderedAccessTable(2));
+    EXPECT_TRUE(d3d12Layout->HasSamplerTable(3));
     EXPECT_EQ(d3d12Layout->GetDesc().constantBufferCount, 1u);
     EXPECT_EQ(d3d12Layout->GetDesc().textureCount, 1u);
     EXPECT_EQ(d3d12Layout->GetDesc().uavCount, 1u);
@@ -295,3 +297,68 @@ TEST_P(RHITestFixture, PipelineLayout_D3D12InfersBindingClassesFromSetLayouts) {
     layout->Shutdown();
     delete layout;
 }
+
+TEST_P(RHITestFixture, PipelineLayout_D3D12SeparatesOverlappingBindingsAcrossSetSlots) {
+    if (GetBackendType() != RHIType::D3D12) {
+        GTEST_SKIP() << "D3D12-specific root parameter verification";
+    }
+
+    DescriptorSetLayoutBinding set0Bindings[2] = {};
+    set0Bindings[0].binding = 0;
+    set0Bindings[0].type = static_cast<uint32_t>(DescriptorType::CBV);
+    set0Bindings[0].count = 1;
+    set0Bindings[1].binding = 0;
+    set0Bindings[1].type = static_cast<uint32_t>(DescriptorType::SRV);
+    set0Bindings[1].count = 1;
+
+    DescriptorSetLayoutBinding set1Bindings[2] = {};
+    set1Bindings[0].binding = 0;
+    set1Bindings[0].type = static_cast<uint32_t>(DescriptorType::CBV);
+    set1Bindings[0].count = 1;
+    set1Bindings[1].binding = 0;
+    set1Bindings[1].type = static_cast<uint32_t>(DescriptorType::SRV);
+    set1Bindings[1].count = 1;
+
+    DescriptorSetLayoutBinding set2Bindings[1] = {};
+    set2Bindings[0].binding = 0;
+    set2Bindings[0].type = static_cast<uint32_t>(DescriptorType::Sampler);
+    set2Bindings[0].count = 1;
+
+    DescriptorSetLayoutDesc setLayouts[3] = {};
+    setLayouts[0].bindings = set0Bindings;
+    setLayouts[0].bindingCount = 2;
+    setLayouts[1].bindings = set1Bindings;
+    setLayouts[1].bindingCount = 2;
+    setLayouts[2].bindings = set2Bindings;
+    setLayouts[2].bindingCount = 1;
+
+    RHIPipelineLayoutDesc desc = {};
+    desc.setLayouts = setLayouts;
+    desc.setLayoutCount = 3;
+
+    RHIPipelineLayout* layout = GetDevice()->CreatePipelineLayout(desc);
+    ASSERT_NE(layout, nullptr);
+
+    auto* d3d12Layout = static_cast<D3D12PipelineLayout*>(layout);
+    EXPECT_TRUE(d3d12Layout->UsesSetLayouts());
+    EXPECT_TRUE(d3d12Layout->HasConstantBufferBinding(0, 0));
+    EXPECT_TRUE(d3d12Layout->HasConstantBufferBinding(1, 0));
+    EXPECT_FALSE(d3d12Layout->HasConstantBufferBinding(2, 0));
+    EXPECT_NE(
+        d3d12Layout->GetConstantBufferRootParameterIndex(0, 0),
+        d3d12Layout->GetConstantBufferRootParameterIndex(1, 0));
+
+    EXPECT_TRUE(d3d12Layout->HasShaderResourceTable(0));
+    EXPECT_TRUE(d3d12Layout->HasShaderResourceTable(1));
+    EXPECT_FALSE(d3d12Layout->HasShaderResourceTable(2));
+    EXPECT_NE(
+        d3d12Layout->GetShaderResourceTableRootParameterIndex(0),
+        d3d12Layout->GetShaderResourceTableRootParameterIndex(1));
+
+    EXPECT_FALSE(d3d12Layout->HasSamplerTable(0));
+    EXPECT_FALSE(d3d12Layout->HasSamplerTable(1));
+    EXPECT_TRUE(d3d12Layout->HasSamplerTable(2));
+
+    layout->Shutdown();
+    delete layout;
+}

tests/TEST_SPEC.md

@@ -174,6 +174,7 @@ tests/RHI/integration/
    - `sphere_opengl.ppm`
 5. 两个后端都必须与同一张 `GT.ppm` 做比对。
 6. 新测试如果暴露抽象层缺口，应先补 RHI，再补测试。
+7. 至少保留一个场景覆盖 `firstSet != 0` 的描述符绑定路径，当前由 `sphere` 负责验证。
 
 ### 6.3 命名