Add highlight to Motion Vectors Debug view for better content optimizing

Source/Engine/Renderer/MotionBlurPass.cpp

@@ -236,20 +236,43 @@ void MotionBlurPass::RenderMotionVectors(RenderContext& renderContext)
 
 void MotionBlurPass::RenderDebug(RenderContext& renderContext, GPUTextureView* frame)
 {
+    auto outputView = renderContext.Task->GetOutputView();
+    auto outputViewport = renderContext.Task->GetOutputViewport();
     auto context = GPUDevice::Instance->GetMainContext();
     const auto motionVectors = renderContext.Buffers->MotionVectors;
+    context->ResetRenderTarget();
     if (!motionVectors || !motionVectors->IsAllocated() || checkIfSkipPass())
     {
+        context->SetRenderTarget(outputView);
+        context->SetViewportAndScissors(outputViewport);
         context->Draw(frame);
         return;
     }
 
+    // Draw depth of objects that draw motion vectors for better debugging content when optimizing this pass
+    auto desc = GPUTextureDescription::New2D(motionVectors->Width(), motionVectors->Height(), PixelFormat::D16_UNorm, GPUTextureFlags::ShaderResource | GPUTextureFlags::DepthStencil);
+    auto motionObjectsDepth = RenderTargetPool::Get(desc);
+    {
+        PROFILE_GPU_CPU("Motion Vectors Depth");
+        context->SetRenderTarget(motionObjectsDepth->View(), nullptr);
+        context->SetViewportAndScissors((float)desc.Width, (float)desc.Height);
+        context->ClearDepth(motionObjectsDepth->View());
+        renderContext.View.Pass = DrawPass::Depth;
+        renderContext.List->ExecuteDrawCalls(renderContext, DrawCallsListType::MotionVectors);
+        context->ResetRenderTarget();
+    }
+
     PROFILE_GPU_CPU("Motion Vectors Debug");
     context->BindSR(0, frame);
     context->BindSR(1, renderContext.Buffers->MotionVectors->View());
+    context->BindSR(2, motionObjectsDepth->View());
     context->SetState(_psMotionVectorsDebug);
+    context->SetRenderTarget(outputView);
+    context->SetViewportAndScissors(outputViewport);
     context->DrawFullscreenTriangle();
     context->ResetSR();
+
+    RenderTargetPool::Release(motionObjectsDepth);
 }
 
 void MotionBlurPass::Render(RenderContext& renderContext, GPUTexture*& frame, GPUTexture*& tmp)

Source/Engine/Renderer/Renderer.cpp

@@ -789,9 +789,6 @@ void RenderInner(SceneRenderTask* task, RenderContext& renderContext, RenderCont
     // Debug motion vectors
     if (renderContext.View.Mode == ViewMode::MotionVectors)
     {
-        context->ResetRenderTarget();
-        context->SetRenderTarget(task->GetOutputView());
-        context->SetViewportAndScissors(outputViewport);
         MotionBlurPass::Instance()->RenderDebug(renderContext, frameBuffer->View());
         RenderTargetPool::Release(tempBuffer);
         RenderTargetPool::Release(frameBuffer);

Source/Shaders/MotionBlur.shader

@@ -71,10 +71,26 @@ float4 MotionVectorToColor(float2 v)
 META_PS(true, FEATURE_LEVEL_ES2)
 float4 PS_MotionVectorsDebug(Quad_VS2PS input) : SV_Target
 {
-	float4 c = SAMPLE_RT(Input0, input.TexCoord);
+	float4 color = SAMPLE_RT(Input0, input.TexCoord);
+
+    // Grey-out background pixels (that don't draw dedicated motion vectors)
+    float motionObjectsDepth = SAMPLE_RT_DEPTH(Input2, input.TexCoord);
+#if REVERSE_Z
+    bool isBackground = motionObjectsDepth <= 0;
+#else
+    bool isBackground = motionObjectsDepth >= 1;
+#endif
+    uint2 checkerboardCoord = (uint2(input.Position.xy) >> 3) & 0x1;
+    float checkerboard = checkerboardCoord.x == checkerboardCoord.y ? 1.0f : 0.0f;
+    float3 backgroundColor = Luminance(color.rgb).xxx * (0.4f + 0.1f * checkerboard);
+    color.rgb = select(isBackground, backgroundColor, max(color.rgb, 0.2f));
+
+    // Debug color based on the pixel motion
     float2 v = SAMPLE_RT(Input1, input.TexCoord).xy * 20.0f;
     float4 vC = MotionVectorToColor(v);
-    return float4(lerp(c.rgb, vC.rgb, vC.a * 0.6f), c.a);
+    color.rgb =  lerp(color.rgb, vC.rgb, vC.a * 0.6f);
+
+    return color;
 }
 
 // Returns the longer velocity vector