Clean out some unnecessary GC.Allocs, and make HybridRendererCommandBuffer warnings sticky so that they do not spill every frame in the event that the command buffer is not getting flushed by OnRender() in the builds. (#87)

Author: pastasfuture

com.unity.render-pipelines.high-definition/Runtime/Lighting/ProbeVolume/ProbeVolumeLighting.cs

@@ -1426,8 +1426,7 @@ ProbeVolumeDebugOverlayParameters PrepareProbeVolumeOverlayParameters(LightingDe
 #if UNITY_EDITOR
             if (UnityEditor.Selection.activeGameObject != null)
             {
-                var selectedProbeVolume = UnityEditor.Selection.activeGameObject.GetComponent<ProbeVolume>();
-                if (selectedProbeVolume != null)
+                if (UnityEditor.Selection.activeGameObject.TryGetComponent(out ProbeVolume selectedProbeVolume))
                 {
                     // User currently has a probe volume selected.
                     // Compute a scaleBias term so that atlas view automatically zooms into selected probe volume.

com.unity.render-pipelines.high-definition/Runtime/Material/MaskVolume/MaskVolumeRendering.cs

@@ -828,8 +828,7 @@ MaskVolumeDebugOverlayParameters PrepareMaskVolumeOverlayParameters(LightingDebu
 #if UNITY_EDITOR
             if (UnityEditor.Selection.activeGameObject != null)
             {
-                var selectedMaskVolume = UnityEditor.Selection.activeGameObject.GetComponent<MaskVolume>();
-                if (selectedMaskVolume != null)
+                if (UnityEditor.Selection.activeGameObject.TryGetComponent(out MaskVolume selectedMaskVolume))
                 {
                     // User currently has a probe volume selected.
                     // Compute a scaleBias term so that atlas view automatically zooms into selected probe volume.

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

@@ -79,6 +79,12 @@ public override int GetHashCode()
 
                 return hash;
             }
+
+            public static readonly HybridRendererCommandBufferSystemHandle zero = new HybridRendererCommandBufferSystemHandle()
+            {
+                systemID = 0,
+                worldID = 0
+            };
         }
 
         private class HybridRendererCommandBufferData
@@ -89,6 +95,10 @@ private class HybridRendererCommandBufferData
             private bool immediateModeEnabled = false;
             private bool immediateModeEnabledNext = false;
 
+#if !UNITY_EDITOR
+            private HybridRendererCommandBufferSystemHandle commandBufferSubmissionStickyWarningHandle = HybridRendererCommandBufferSystemHandle.zero;
+#endif
+
             public void EnsureProfilingSampler(string name, HybridRendererCommandBufferSystemHandle handle)
             {
                 if (!profilingSamplers.TryGetValue(handle.systemID, out var profilingSampler))
@@ -120,9 +130,19 @@ public CommandBuffer Begin(HybridRendererCommandBufferSystemHandle handle)
                     SubmitImmediate();
 
 #if !UNITY_EDITOR
-                    Debug.LogWarning("Warning: HybridRendererCommandBuffer: Encountered unexpected case of a command buffer having not been submitted between Simulation Update loops. It should have been submitted in the HDRenderPipeline::Render() loop.");
+                    if (commandBufferSubmissionStickyWarningHandle != handle)
+                    {
+                        commandBufferSubmissionStickyWarningHandle = handle;
+                        Debug.LogWarning("Warning: HybridRendererCommandBuffer: Encountered unexpected case of a command buffer having not been submitted between Simulation Update loops. It should have been submitted in the HDRenderPipeline::Render() loop.");
+                    }
 #endif
                 }
+#if !UNITY_EDITOR
+                else if (handle == commandBufferSubmissionStickyWarningHandle)
+                {
+                    commandBufferSubmissionStickyWarningHandle = HybridRendererCommandBufferSystemHandle.zero;
+                }
+#endif
                 debugSubmittedSystemState.Add(handle, false);
 
                 var cmd = EnsureCommandBuffer();
@@ -134,7 +154,12 @@ public void End(HybridRendererCommandBufferSystemHandle handle)
             {
                 if (debugSubmittedSystemState.TryGetValue(handle, out bool submitted))
                 {
-                    Debug.AssertFormat(submitted == false, "Error: Encountered Hybrid Rendering System {0} with an already submitted command buffer. Was End() already called in this Simulation Update?", profilingSamplers[handle.systemID].name);
+                    if (submitted)
+                    {
+                        // Guard assert in if block so that we do not pay the GC.Alloc cost of accessing a ProfilingSampler.name.
+                        Debug.AssertFormat(false, "Error: Encountered Hybrid Rendering System {0} with an already submitted command buffer. Was End() already called in this Simulation Update?", profilingSamplers[handle.systemID].name);
+                    }
+                    
                 }
                 else
                 {