[Backport 2021.2] Add Overlay Render Queue to Custom Pass

Backport: #6520

Address case https://fogbugz.unity3d.com/f/cases/1379399/

The original request of this bug report was to add support for the Overlay render queue to HDRP.

Since overlay is an invalid render queue range for HDRP's internal draw calls, I instead explored the route of ensuring that the custom pass volume is capable over drawing renderers in this queue. I found that the Draw Renderers Custom Pass did not include the Overlay range, so I added it.

Author: johnpars

Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/HDRenderQueue.cs

@@ -101,6 +101,8 @@ internal static RenderQueueType MigrateRenderQueueToHDRP10(RenderQueueType rende
 
         public static readonly RenderQueueRange k_RenderQueue_AfterPostProcessTransparent = new RenderQueueRange { lowerBound = (int)Priority.AfterPostprocessTransparentFirst, upperBound = (int)Priority.AfterPostprocessTransparentLast };
 
+        public static readonly RenderQueueRange k_RenderQueue_Overlay = new RenderQueueRange { lowerBound = (int)Priority.Overlay, upperBound = 5000 };
+
         public static readonly RenderQueueRange k_RenderQueue_All = new RenderQueueRange { lowerBound = 0, upperBound = 5000 };
 
         public static bool Contains(this RenderQueueRange range, int value) => range.lowerBound <= value && value <= range.upperBound;

Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/RenderPass/CustomPass/CustomPass.cs

@@ -110,27 +110,29 @@ public enum TargetBuffer
         public enum RenderQueueType
         {
             /// <summary>Opaque GameObjects without alpha test only.</summary>
-            OpaqueNoAlphaTest,
+            OpaqueNoAlphaTest = 0,
             /// <summary>Opaque GameObjects with alpha test only.</summary>
-            OpaqueAlphaTest,
+            OpaqueAlphaTest = 1,
             /// <summary>All opaque GameObjects.</summary>
-            AllOpaque,
+            AllOpaque = 2,
             /// <summary>Opaque GameObjects that use the after post process render pass.</summary>
-            AfterPostProcessOpaque,
+            AfterPostProcessOpaque = 3,
             /// <summary>Transparent GameObjects that use the the pre refraction render pass.</summary>
-            PreRefraction,
+            PreRefraction = 4,
             /// <summary>Transparent GameObjects that use the default render pass.</summary>
-            Transparent,
+            Transparent = 5,
             /// <summary>Transparent GameObjects that use the low resolution render pass.</summary>
-            LowTransparent,
+            LowTransparent = 6,
             /// <summary>All Transparent GameObjects.</summary>
-            AllTransparent,
+            AllTransparent = 7,
             /// <summary>Transparent GameObjects that use the Pre-refraction, Default, or Low resolution render pass.</summary>
-            AllTransparentWithLowRes,
+            AllTransparentWithLowRes = 8,
             /// <summary>Transparent GameObjects that use after post process render pass.</summary>
-            AfterPostProcessTransparent,
+            AfterPostProcessTransparent = 9,
+            /// <summary>All GameObjects that use the overlay render pass.</summary>
+            Overlay = 11,
             /// <summary>All GameObjects</summary>
-            All,
+            All = 10,
         }
 
         internal struct RenderTargets

Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/RenderPass/CustomPass/CustomPassUtils.cs

@@ -412,6 +412,7 @@ public static RenderQueueRange GetRenderQueueRangeFromRenderQueueType(CustomPass
                 case CustomPass.RenderQueueType.AllTransparent: return HDRenderQueue.k_RenderQueue_AllTransparent;
                 case CustomPass.RenderQueueType.AllTransparentWithLowRes: return HDRenderQueue.k_RenderQueue_AllTransparentWithLowRes;
                 case CustomPass.RenderQueueType.AfterPostProcessTransparent: return HDRenderQueue.k_RenderQueue_AfterPostProcessTransparent;
+                case CustomPass.RenderQueueType.Overlay: return HDRenderQueue.k_RenderQueue_Overlay;
                 case CustomPass.RenderQueueType.All:
                 default:
                     return HDRenderQueue.k_RenderQueue_All;