[HDRP] Fix RenderGraph issue with Forward mode, debug mode and VT.

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

@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Fixed
 - Fixed issue where some ShaderGraph generated shaders were not SRP compatible because of UnityPerMaterial cbuffer layout mismatches (case 1292501)
+- Fixed Rendergraph issue with virtual texturing and debug mode while in forward.
 
 ### Changed
 - Rename HDRP sub menu in Assets/Create/Shader to HD Render Pipeline for consistency.

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

@@ -236,12 +236,14 @@ void ExecuteWithRenderGraph(RenderRequest           renderRequest,
 
                 // Render gizmos that should be affected by post processes
                 RenderGizmos(m_RenderGraph, hdCamera, colorBuffer, GizmoSubset.PreImageEffects);
-            }
 
 #if ENABLE_VIRTUALTEXTURES
-            m_VtBufferManager.Resolve(m_RenderGraph, hdCamera, vtFeedbackBuffer);
-            PushFullScreenVTFeedbackDebugTexture(m_RenderGraph, vtFeedbackBuffer, msaa);
+                // Note: This pass rely on availability of vtFeedbackBuffer buffer (i.e it need to be write before we read it here)
+                // We don't write it when doing debug mode, FullScreenDebug mode or path tracer. Thus why this pass is call here.
+                m_VtBufferManager.Resolve(m_RenderGraph, hdCamera, vtFeedbackBuffer);
+                PushFullScreenVTFeedbackDebugTexture(m_RenderGraph, vtFeedbackBuffer, msaa);
 #endif
+            }
 
             // At this point, the color buffer has been filled by either debug views are regular rendering so we can push it here.
             var colorPickerTexture = PushColorPickerDebugTexture(m_RenderGraph, colorBuffer);