Probe Volumes: Use GlobalObjectId.targetObjectId (#16)

* Probe Volumes: Use GlobalObjectId.targetObjectId to uniquely identify Probe Volumes, and Probe Volume Asset ownership, rather than GetInstanceID() - which was not guarenteed to be persistent. This PR cleans up the related logic, allowing us to guarentee non-colliding bake ids, avoids hanging on to asset references during duplication of probe volumes, and, in the case where you have intentionally referenced a probe volume asset on a probe volume that does not own it, avoids baking that asset, which would previously stomp source data.

* Probe Volumes: GlobalUniqueID: Use a custom stack-only + packed representation of the full GlobalObjectId, rather than only using GlobalObjectID.targetObjectId to avoid collisions when different scene probe volumes happen to have the same targetObjectId. This also allows full backwards asset lookup in the future if necessary, which should help debugging + build tools.

Co-authored-by: pastasfuture <[email protected]>

Author: pastasfuture

com.unity.render-pipelines.high-definition/Editor/Lighting/ProbeVolume/ProbeVolumeSHPreview.shader

@@ -5,7 +5,7 @@ Shader "Hidden/Debug/ProbeVolumeSHPreview"
         _Exposure("_Exposure", Range(-10.0,10.0)) = 0.0
         _ProbeVolumeResolution("_ProbeVolumeResolution", Vector) = (0, 0, 0, 0)
         _ProbeVolumeProbeDisplayRadiusWS("_ProbeVolumeProbeDisplayRadiusWS", Float) = 1.0
-        _ProbeVolumeAtlasBias("_ProbeVolumeAtlasBias", Vector) = (0, 0, 0, 0)
+        _ProbeVolumeAtlasBiasTexels("_ProbeVolumeAtlasBiasTexels", Vector) = (0, 0, 0, 0)
         _ProbeVolumeIsResidentInAtlas("_ProbeVolumeIsResidentInAtlas", Float) = 0.0
         _ProbeVolumeHighlightNegativeRinging("_ProbeVolumeHighlightNegativeRinging", Float) = 0.0
         _ProbeVolumeDrawValidity("_ProbeVolumeDrawValidity", Float) = 0.0
@@ -56,7 +56,7 @@ Shader "Hidden/Debug/ProbeVolumeSHPreview"
             float3 _ProbeVolumeResolution;
             float4x4 _ProbeIndex3DToPositionWSMatrix;
             float _ProbeVolumeProbeDisplayRadiusWS;
-            float3 _ProbeVolumeAtlasBias;
+            float3 _ProbeVolumeAtlasBiasTexels;
             int _ProbeVolumeIsResidentInAtlas;
             int _ProbeVolumeHighlightNegativeRinging;
             int _ProbeVolumeDrawValidity;
@@ -205,7 +205,7 @@ Shader "Hidden/Debug/ProbeVolumeSHPreview"
                 {
                     // Due to probeIndex3D getting stored as a float and interpolated, we need to round before converting to int.
                     // Otherwise our texel coordinate will oscillate between probes randomly (based on precision).
-                    int3 probeIndexAtlas3D = (int3)(i.probeIndex3D + 0.5 + _ProbeVolumeAtlasBias);
+                    int3 probeIndexAtlas3D = (int3)(i.probeIndex3D + 0.5 + _ProbeVolumeAtlasBiasTexels);
 
                     probeSampleData = SampleProbeData(probeIndexAtlas3D, normalWS);
                 }

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

@@ -14,9 +14,7 @@ namespace UnityEngine.Rendering.HighDefinition
     public class AdditionalGIBakeRequestsManager
     {
         // The baking ID for the extra requests
-        // TODO: Need to ensure this never conflicts with bake IDs from others interacting with the API.
-        // In our project, this is ProbeVolumes.
-        internal static readonly int s_BakingID = 912345678;
+        internal static readonly int s_BakingID = int.MaxValue;
 
         private static AdditionalGIBakeRequestsManager s_Instance = new AdditionalGIBakeRequestsManager();
         /// <summary>
@@ -28,6 +26,9 @@ private AdditionalGIBakeRequestsManager()
         {
             if (!Application.isPlaying)
             {
+                lightmapperBakeIDFromBakeID.Clear();
+                lightmapperBakeIDNext = 0;
+
                 SubscribeOnBakeStarted();
             }
         }
@@ -37,6 +38,9 @@ private AdditionalGIBakeRequestsManager()
             if (!Application.isPlaying)
             {
                 UnsubscribeOnBakeStarted();
+
+                lightmapperBakeIDFromBakeID.Clear();
+                lightmapperBakeIDNext = 0;
             }
         }
 
@@ -48,6 +52,36 @@ private AdditionalGIBakeRequestsManager()
 
         private static readonly Vector2 s_FreelistSentinel = new Vector2(float.MaxValue, float.MaxValue);
 
+        // Lightmapper API uses ints as keys, but we want to use full, stable, GlobalObjectIds as keys.
+        // Rather than hashing and hoping we don't collide, lets handle this robustly by
+        // keeping a dictionary of ProbeVolumeGlobalUniqueID->int bit keys.
+        private Dictionary<ProbeVolumeGlobalUniqueID, int> lightmapperBakeIDFromBakeID = new Dictionary<ProbeVolumeGlobalUniqueID, int>(32);
+        private int lightmapperBakeIDNext = 0;
+
+        internal bool TryGetLightmapperBakeIDFromBakeID(ProbeVolumeGlobalUniqueID bakeID, out int lightmapperBakeID)
+        {
+            bool success = false;
+            if (lightmapperBakeIDFromBakeID.TryGetValue(bakeID, out lightmapperBakeID))
+            {
+                success = true;
+            }
+            else if (lightmapperBakeIDNext == s_BakingID)
+            {
+                success = false;
+                lightmapperBakeID = -1;
+                Debug.LogWarningFormat("Error: Used up all lightmapper bake IDs. This should never happen. Somehow all {0} ids have been used up. This must be the result of a bug. Unlikely that you created and baked {0} unique bake requests. Quit and reopen unity to flush all IDs.", s_BakingID - 1);
+            }
+            else
+            {
+                success = true;
+                lightmapperBakeID = lightmapperBakeIDNext;
+                ++lightmapperBakeIDNext;
+                lightmapperBakeIDFromBakeID.Add(bakeID, lightmapperBakeID);
+            }
+
+            return success;
+        }
+
         /// <summary>
         /// Enqueue a request for probe rendering at the specified location.
         /// </summary>
@@ -282,4 +316,4 @@ private void EnsureRequestPositionsSanitized()
         }
     }
 }
-#endif
+#endif

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

@@ -15,8 +15,7 @@ interface IProbeVolumeList
 
         ref ProbeVolumeArtistParameters GetParameters(int i);
 
-        int GetAtlasID(int i);
-        int GetBakeID(int i);
+        ProbeVolumeGlobalUniqueID GetAtlasID(int i);
         ProbeVolume.ProbeVolumeAtlasKey ComputeProbeVolumeAtlasKey(int i);
         ProbeVolume.ProbeVolumeAtlasKey GetProbeVolumeAtlasKeyPrevious(int i);
         void SetProbeVolumeAtlasKeyPrevious(int i, ProbeVolume.ProbeVolumeAtlasKey key);