Fixes for vertex layouts binding into graphics backend

Source/Engine/Graphics/Shaders/GPUVertexLayout.cpp

@@ -262,7 +262,9 @@ GPUVertexLayout* GPUVertexLayout::Merge(GPUVertexLayout* base, GPUVertexLayout*
                 {
                     // Insert any missing elements
                     VertexElement ne = { e.Type, missingSlotOverride != -1 ? (byte)missingSlotOverride : e.Slot, 0, e.PerInstance, e.Format };
-                    if (e.Type == VertexElement::Types::TexCoord1 || e.Type == VertexElement::Types::TexCoord2 || e.Type == VertexElement::Types::TexCoord3)
+                    if (e.Type == VertexElement::Types::TexCoord1 || 
+                        e.Type == VertexElement::Types::TexCoord2 || 
+                        e.Type == VertexElement::Types::TexCoord3)
                     {
                         // Alias missing texcoords with existing texcoords
                         for (const VertexElement& ee : newElements)

Source/Engine/GraphicsDevice/DirectX/DX11/GPUShaderDX11.cpp

@@ -26,7 +26,11 @@ ID3D11InputLayout* GPUShaderProgramVSDX11::GetInputLayout(GPUVertexLayoutDX11* v
     {
         if (vertexLayout && vertexLayout->InputElementsCount)
         {
-            auto mergedVertexLayout = (GPUVertexLayoutDX11*)GPUVertexLayout::Merge(vertexLayout, Layout ? Layout : InputLayout);
+            GPUVertexLayoutDX11* mergedVertexLayout = vertexLayout;
+            if (!mergedVertexLayout)
+                mergedVertexLayout = (GPUVertexLayoutDX11*)Layout; // Fallback to shader-specified layout (if using old APIs)
+            if (InputLayout)
+                mergedVertexLayout = (GPUVertexLayoutDX11*)GPUVertexLayout::Merge(mergedVertexLayout, InputLayout);
             LOG_DIRECTX_RESULT(vertexLayout->GetDevice()->GetDevice()->CreateInputLayout(mergedVertexLayout->InputElements, mergedVertexLayout->InputElementsCount, Bytecode.Get(), Bytecode.Length(), &inputLayout));
         }
         _cache.Add(vertexLayout, inputLayout);

Source/Engine/GraphicsDevice/DirectX/DX12/GPUContextDX12.cpp

@@ -563,7 +563,7 @@ void GPUContextDX12::flushPS()
         // Change state
         ASSERT(_currentState->IsValid());
 #if GPU_ENABLE_ASSERTION_LOW_LAYERS
-        if (!_vertexLayout && _vbHandles[0] && !_currentState->VertexLayout)
+        if (!_vertexLayout && _vbHandles[0] && !_currentState->VertexBufferLayout)
         {
             LOG(Error, "Missing Vertex Layout (not assigned to GPUBuffer). Vertex Shader won't read valid data resulting incorrect visuals.");
         }
@@ -957,7 +957,6 @@ void GPUContextDX12::BindUA(int32 slot, GPUResourceView* view)
 void GPUContextDX12::BindVB(const Span<GPUBuffer*>& vertexBuffers, const uint32* vertexBuffersOffsets, GPUVertexLayout* vertexLayout)
 {
     ASSERT(vertexBuffers.Length() >= 0 && vertexBuffers.Length() <= GPU_MAX_VB_BINDED);
-
     bool vbEdited = _vbCount != vertexBuffers.Length();
     D3D12_VERTEX_BUFFER_VIEW views[GPU_MAX_VB_BINDED];
     for (int32 i = 0; i < vertexBuffers.Length(); i++)
@@ -990,7 +989,13 @@ void GPUContextDX12::BindVB(const Span<GPUBuffer*>& vertexBuffers, const uint32*
 #endif
         _commandList->IASetVertexBuffers(0, vertexBuffers.Length(), views);
     }
-    _vertexLayout = (GPUVertexLayoutDX12*)(vertexLayout ? vertexLayout : GPUVertexLayout::Get(vertexBuffers));
+    if (!vertexLayout)
+         vertexLayout = GPUVertexLayout::Get(vertexBuffers);
+    if (_vertexLayout != vertexLayout)
+    {
+        _vertexLayout = (GPUVertexLayoutDX12*)vertexLayout;
+        _psDirtyFlag = true;
+    }
 }
 
 void GPUContextDX12::BindIB(GPUBuffer* indexBuffer)

Source/Engine/GraphicsDevice/DirectX/DX12/GPUPipelineStateDX12.cpp

@@ -83,9 +83,20 @@ ID3D12PipelineState* GPUPipelineStateDX12::GetState(GPUTextureViewDX12* depth, i
     _desc.SampleDesc.Quality = key.MSAA == MSAALevel::None ? 0 : GPUDeviceDX12::GetMaxMSAAQuality((int32)key.MSAA);
     _desc.SampleMask = D3D12_DEFAULT_SAMPLE_MASK;
     _desc.DSVFormat = RenderToolsDX::ToDxgiFormat(PixelFormatExtensions::FindDepthStencilFormat(key.DepthFormat));
-    vertexLayout = (GPUVertexLayoutDX12*)GPUVertexLayout::Merge(vertexLayout, VertexLayout);
-    _desc.InputLayout.pInputElementDescs = vertexLayout ? vertexLayout->InputElements : nullptr;
-    _desc.InputLayout.NumElements = vertexLayout ? vertexLayout->InputElementsCount : 0;
+    if (!vertexLayout)
+        vertexLayout = VertexBufferLayout; // Fallback to shader-specified layout (if using old APIs)
+    if (vertexLayout)
+    {
+        if (VertexInputLayout)
+            vertexLayout = (GPUVertexLayoutDX12*)GPUVertexLayout::Merge(vertexLayout, VertexInputLayout);
+        _desc.InputLayout.pInputElementDescs = vertexLayout->InputElements;
+        _desc.InputLayout.NumElements = vertexLayout->InputElementsCount;
+    }
+    else
+    {
+        _desc.InputLayout.pInputElementDescs = nullptr;
+        _desc.InputLayout.NumElements = 0;
+    }
 
     // Create object
     const HRESULT result = _device->GetDevice()->CreateGraphicsPipelineState(&_desc, IID_PPV_ARGS(&state));
@@ -180,7 +191,11 @@ bool GPUPipelineStateDX12::Init(const Description& desc)
     INIT_SHADER_STAGE(PS, GPUShaderProgramPSDX12);
 
     // Input Assembly
-    VertexLayout = desc.VS ? (GPUVertexLayoutDX12*)(desc.VS->Layout ? desc.VS->Layout : desc.VS->InputLayout) : nullptr;
+    if (desc.VS)
+    {
+        VertexBufferLayout = (GPUVertexLayoutDX12*)desc.VS->Layout;
+        VertexInputLayout = (GPUVertexLayoutDX12*)desc.VS->InputLayout;
+    }
     const D3D12_PRIMITIVE_TOPOLOGY_TYPE primTypes1[] =
     {
         D3D12_PRIMITIVE_TOPOLOGY_TYPE_UNDEFINED,

Source/Engine/GraphicsDevice/DirectX/DX12/GPUPipelineStateDX12.h

@@ -58,7 +58,8 @@ public:
 public:
     D3D_PRIMITIVE_TOPOLOGY PrimitiveTopology = D3D_PRIMITIVE_TOPOLOGY_UNDEFINED;
     DxShaderHeader Header;
-    GPUVertexLayoutDX12* VertexLayout;
+    GPUVertexLayoutDX12* VertexBufferLayout = nullptr;
+    GPUVertexLayoutDX12* VertexInputLayout = nullptr;
 
     /// <summary>
     /// Gets DirectX 12 graphics pipeline state object for the given rendering state. Uses depth buffer and render targets formats and multi-sample levels to setup a proper PSO. Uses caching.

Source/Engine/ShadersCompilation/DirectX/ShaderCompilerD3D.cpp

@@ -277,7 +277,7 @@ bool ShaderCompilerD3D::CompileShader(ShaderFunctionMeta& meta, WritePermutation
             {
                 D3D11_SIGNATURE_PARAMETER_DESC inputDesc;
                 reflector->GetInputParameterDesc(inputIdx, &inputDesc);
-                if (inputDesc.ReadWriteMask == 0 || inputDesc.SystemValueType != D3D10_NAME_UNDEFINED)
+                if (inputDesc.SystemValueType != D3D10_NAME_UNDEFINED)
                     continue;
                 auto format = PixelFormat::Unknown;
                 switch (inputDesc.ComponentType)

Source/Engine/ShadersCompilation/DirectX/ShaderCompilerDX.cpp

@@ -327,7 +327,7 @@ bool ShaderCompilerDX::CompileShader(ShaderFunctionMeta& meta, WritePermutationD
             {
                 D3D12_SIGNATURE_PARAMETER_DESC inputDesc;
                 shaderReflection->GetInputParameterDesc(inputIdx, &inputDesc);
-                if (inputDesc.ReadWriteMask == 0 || inputDesc.SystemValueType != D3D10_NAME_UNDEFINED)
+                if (inputDesc.SystemValueType != D3D10_NAME_UNDEFINED)
                     continue;
                 auto format = PixelFormat::Unknown;
                 switch (inputDesc.ComponentType)