Add support for sampling Scene Color in transparent materials (forward pass)

Source/Engine/Graphics/Materials/ForwardMaterialShader.cpp

@@ -70,7 +70,7 @@ void ForwardMaterialShader::Bind(BindParameters& params)
     MaterialParameter::BindMeta bindMeta;
     bindMeta.Context = context;
     bindMeta.Constants = cb;
-    bindMeta.Input = nullptr; // forward pass materials cannot sample scene color for now
+    bindMeta.Input = params.Input;
     bindMeta.Buffers = params.RenderContext.Buffers;
     bindMeta.CanSampleDepth = GPUDevice::Instance->Limits.HasReadOnlyDepth;
     bindMeta.CanSampleGBuffer = true;

Source/Engine/Graphics/Materials/MaterialParams.cpp

@@ -400,11 +400,13 @@ void MaterialParameter::Bind(BindMeta& meta) const
             {
             case MaterialSceneTextures::SceneDepth:
                 view = meta.CanSampleDepth
-                           ? (GPUDevice::Instance->Limits.HasReadOnlyDepth ? meta.Buffers->DepthBuffer->ViewReadOnlyDepth() : meta.Buffers->DepthBuffer->View())
+                           ? meta.Buffers->DepthBuffer->GetDescription().Flags & GPUTextureFlags::ReadOnlyDepthView ? meta.Buffers->DepthBuffer->ViewReadOnlyDepth() : meta.Buffers->DepthBuffer->View()
                            : GPUDevice::Instance->GetDefaultWhiteTexture()->View();
                 break;
             case MaterialSceneTextures::AmbientOcclusion:
             case MaterialSceneTextures::BaseColor:
+            case MaterialSceneTextures::DiffuseColor:
+            case MaterialSceneTextures::SpecularColor:
                 view = meta.CanSampleGBuffer ? meta.Buffers->GBuffer0->View() : nullptr;
                 break;
             case MaterialSceneTextures::WorldNormal:

Source/Engine/Renderer/ForwardPass.cpp

@@ -74,10 +74,7 @@ void ForwardPass::Dispose()
 void ForwardPass::Render(RenderContext& renderContext, GPUTexture* input, GPUTexture* output)
 {
     PROFILE_GPU_CPU("Forward");
-
+    auto context = GPUDevice::Instance->GetMainContext();
-    // Cache data
-    auto device = GPUDevice::Instance;
-    auto context = device->GetMainContext();
     auto& view = renderContext.View;
     auto mainCache = renderContext.List;
 
@@ -141,6 +138,6 @@ void ForwardPass::Render(RenderContext& renderContext, GPUTexture* input, GPUTex
         // Run forward pass
         view.Pass = DrawPass::Forward;
         context->SetRenderTarget(depthBufferHandle, output->View());
-        mainCache->ExecuteDrawCalls(renderContext, forwardList);
+        mainCache->ExecuteDrawCalls(renderContext, forwardList, input->View());
     }
 }

Source/Engine/Renderer/RenderList.cpp

@@ -553,7 +553,7 @@ bool CanUseInstancing(DrawPass pass)
     return pass == DrawPass::GBuffer || pass == DrawPass::Depth;
 }
 
-void RenderList::ExecuteDrawCalls(const RenderContext& renderContext, DrawCallsList& list)
+void RenderList::ExecuteDrawCalls(const RenderContext& renderContext, DrawCallsList& list, GPUTextureView* input)
 {
     if (list.IsEmpty())
         return;
@@ -625,6 +625,7 @@ DRAW:
 
     // Execute draw calls
     MaterialBase::BindParameters bindParams(context, renderContext);
+    bindParams.Input = input;
     if (useInstancing)
     {
         int32 instanceBufferOffset = 0;

Source/Engine/Renderer/RenderList.h

@@ -564,9 +564,10 @@ public:
     /// </summary>
     /// <param name="renderContext">The rendering context.</param>
     /// <param name="listType">The collected draw calls list type.</param>
-    API_FUNCTION() FORCE_INLINE void ExecuteDrawCalls(API_PARAM(Ref) const RenderContext& renderContext, DrawCallsListType listType)
+    /// <param name="input">The input scene color. It's optional and used in forward/postFx rendering.</param>
+    API_FUNCTION() FORCE_INLINE void ExecuteDrawCalls(API_PARAM(Ref) const RenderContext& renderContext, DrawCallsListType listType, GPUTextureView* input = nullptr)
     {
-        ExecuteDrawCalls(renderContext, DrawCallsLists[(int32)listType]);
+        ExecuteDrawCalls(renderContext, DrawCallsLists[(int32)listType], input);
     }
 
     /// <summary>
@@ -574,7 +575,8 @@ public:
     /// </summary>
     /// <param name="renderContext">The rendering context.</param>
     /// <param name="list">The collected draw calls list.</param>
-    void ExecuteDrawCalls(const RenderContext& renderContext, DrawCallsList& list);
+    /// <param name="input">The input scene color. It's optional and used in forward/postFx rendering.</param>
+    void ExecuteDrawCalls(const RenderContext& renderContext, DrawCallsList& list, GPUTextureView* input = nullptr);
 };
 
 /// <summary>

Source/Engine/Renderer/Renderer.cpp

@@ -45,7 +45,6 @@ Array<RendererPassBase*> PassList(64);
 class RendererService : public EngineService
 {
 public:
-
     RendererService()
         : EngineService(TEXT("Renderer"), 20)
     {
@@ -429,8 +428,9 @@ void RenderInner(SceneRenderTask* task, RenderContext& renderContext)
     }
 
     // Run forward pass
-    auto forwardPassResult = renderContext.Buffers->RT1_FloatRGB;
+    GPUTexture* frameBuffer = renderContext.Buffers->RT1_FloatRGB;
-    ForwardPass::Instance()->Render(renderContext, lightBuffer, forwardPassResult);
+    GPUTexture* tempBuffer = renderContext.Buffers->RT2_FloatRGB;
+    ForwardPass::Instance()->Render(renderContext, lightBuffer, frameBuffer);
 
     // Cleanup
     context->ResetRenderTarget();
@@ -443,16 +443,10 @@ void RenderInner(SceneRenderTask* task, RenderContext& renderContext)
     {
         context->SetRenderTarget(task->GetOutputView());
         context->SetViewportAndScissors(task->GetOutputViewport());
-        context->Draw(forwardPassResult);
+        context->Draw(frameBuffer);
         return;
     }
 
-    // Prepare buffers for post processing frame
-    GPUTexture* frameBuffer = renderContext.Buffers->RT1_FloatRGB;
-    GPUTexture* tempBuffer = renderContext.Buffers->RT2_FloatRGB;
-    if (forwardPassResult == tempBuffer)
-        Swap(frameBuffer, tempBuffer);
-
     // Material and Custom PostFx
     renderContext.List->RunMaterialPostFxPass(context, renderContext, MaterialPostFxLocation::BeforePostProcessingPass, frameBuffer, tempBuffer);
     renderContext.List->RunCustomPostFxPass(context, renderContext, PostProcessEffectLocation::BeforePostProcessingPass, frameBuffer, tempBuffer);