Stop Uber from running if no effect that needs it is enabled

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -79,6 +79,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed cached directional light shadows disappearing without reappearing when the going outside of the range of shadow validity.
 - Fixed an issue where sometimes full screen debug would cause render graph errors.
 - Fixed a nullref exception when creating a new scene while LightExplorer is open.
+- Fixed issue that caused the uber post process to run even if nothing is to be done, leading to different results when disabling every post process manually vs disabling the whole post-processing pipeline.
 
 ## [14.0.0] - 2021-11-17
 

com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/HDRenderPipeline.PostProcess.cs

@@ -4614,6 +4614,14 @@ class UberPostPassData
         TextureHandle UberPass(RenderGraph renderGraph, HDCamera hdCamera, TextureHandle logLut, TextureHandle bloomTexture, TextureHandle source)
         {
             bool isSceneView = hdCamera.camera.cameraType == CameraType.SceneView;
+            var featureFlags = GetUberFeatureFlags(isSceneView);
+            // If we have nothing to do in Uber post we just skip it.
+            if (featureFlags == UberPostFeatureFlags.None && !m_ColorGradingFS && !m_BloomFS &&
+                m_CurrentDebugDisplaySettings.data.fullScreenDebugMode != FullScreenDebugMode.ColorLog)
+            {
+                return source;
+            }
+
             using (var builder = renderGraph.AddRenderPass<UberPostPassData>("Uber Post", out var passData, ProfilingSampler.Get(HDProfileId.UberPost)))
             {
                 TextureHandle dest = GetPostprocessOutputHandle(renderGraph, "Uber Post Destination");
@@ -4622,7 +4630,7 @@ TextureHandle UberPass(RenderGraph renderGraph, HDCamera hdCamera, TextureHandle
                 // if they are used or not so they can set default values if needed
                 passData.uberPostCS = defaultResources.shaders.uberPostCS;
                 passData.uberPostCS.shaderKeywords = null;
-                var featureFlags = GetUberFeatureFlags(isSceneView);
+
                 passData.uberPostKernel = passData.uberPostCS.FindKernel("Uber");
                 if (PostProcessEnableAlpha())
                 {