DGI Fix Leak Mitigation (#68)

* Fixed DGI axis bit packing.
* Store neighbor validity in axis and limit propagation from an invalid probe instead of limiting propagation towards an invalid probe.
* Set default Baked Emission Multiplier, Sky Multiplier and Leak Multiplier to 1.0.

Author: AndrewSaraevUnity

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

@@ -1,14 +1,5 @@
 using System;
-using UnityEngine.Rendering;
-using UnityEngine.Serialization;
-using UnityEditor.Experimental;
-using Unity.Collections;
-using System.Collections.Generic;
 using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
-using UnityEditor;
-using UnityEditor.Rendering.HighDefinition;
-using UnityEngine.Experimental.Rendering;
 
 [assembly: InternalsVisibleTo("Unity.Entities.Hybrid.HybridComponents")]
 [assembly: InternalsVisibleTo("Unity.Rendering.Hybrid")]
@@ -18,13 +9,13 @@ namespace UnityEngine.Rendering.HighDefinition
     public class ProbeDynamicGI : VolumeComponent
     {
         [Tooltip("Indirect multiplier for all lights affect Dynamic GI")]
-        public ClampedFloatParameter indirectMultiplier = new ClampedFloatParameter(1f, 0.0f, 2f);
+        public ClampedFloatParameter indirectMultiplier = new ClampedFloatParameter(1f, 0f, 2f);
         [Tooltip("Multiplier for material emissive colors that affect Dynamic GI")]
-        public ClampedFloatParameter bakedEmissionMultiplier = new ClampedFloatParameter(0f, 0f, 2f);
+        public ClampedFloatParameter bakedEmissionMultiplier = new ClampedFloatParameter(1f, 0f, 2f);
         [Tooltip("Multiplier for sky lighting that affect Dynamic GI of")]
-        public ClampedFloatParameter skyMultiplier = new ClampedFloatParameter(0f, 0f, 2f);
+        public ClampedFloatParameter skyMultiplier = new ClampedFloatParameter(1f, 0f, 2f);
         [Tooltip("A control for blending in more influence of infinite bounce light near surfaces")]
-        public ClampedFloatParameter infiniteBounce = new ClampedFloatParameter(1f, 0.0f, 2f);
+        public ClampedFloatParameter infiniteBounce = new ClampedFloatParameter(1f, 0f, 2f);
         [Tooltip("Limits albedo value used for infinite bounces to prevent lighting from blowing up")]
         public ClampedFloatParameter maxAlbedo = new ClampedFloatParameter(0.9f, 0f, 1f);
         [Tooltip("Advanced control for the contribution amount of secondary propagation indirect light")]
@@ -43,8 +34,8 @@ public class ProbeDynamicGI : VolumeComponent
         public ClampedFloatParameter sharpness = new ClampedFloatParameter(6.0f, 0.0f, 16.0f);
         [Tooltip("Advanced control for the SG sharpness used when propagating light")]
         public ClampedFloatParameter propagationSharpness = new ClampedFloatParameter(2.0f, 0.0f, 16.0f);
-        [Tooltip("Advanced control for darkening down the indirect light on invalid probes")]
-        public ClampedFloatParameter leakMultiplier = new ClampedFloatParameter(0.0f, 0.0f, 1.0f);
+        [Tooltip("Advanced control for darkening down the indirect light coming from invalid probes")]
+        public ClampedFloatParameter leakMultiplier = new ClampedFloatParameter(1.0f, 0.0f, 1.0f);
         [Tooltip("Advanced control to bias the distance from the normal of the hit surface to perform direct lighting evaluation on")]
         public ClampedFloatParameter bias = new ClampedFloatParameter(0.05f, 0.0f, 0.33f);
         [Tooltip("Advanced control for how probes at volume boundaries propagate light from neighboring Probe Volumes.\n\nDisabled: No light is propagated across neighbors.\n\nSample Neighbors Direction Only: Samples all probe volumes once per probe and evaluates light from the resulting probe data for each axis.\n\nSample Neighbors Position and Direction: Samples all probe volumes for all propagation axes at each axes neighboring probe position.\nPotentially more accurate than Sample Neighbors Direction Only, but significantly more expensive.")]

com.unity.render-pipelines.high-definition/Runtime/Lighting/ProbeVolume/DynamicGI/ProbePropagation.hlsl

@@ -26,21 +26,10 @@ float3 ReadPreviousPropagationAxis(uint probeIndex, uint axisIndex)
     return _PreviousRadianceCacheAxis[index];
 }
 
-float3 NormalizeOutputRadiance(float3 lighting, float probeValidity)
+float InvalidScale(float probeValidity)
 {
     float validity = pow(1.0 - probeValidity, 8.0);
-    const float invalidScale = (1.0f - lerp(_LeakMultiplier, 0.0f, validity));
-
-    float3 radiance = lighting * invalidScale;
-
-    return radiance;
-}
-
-void WritePropagationOutput(uint index, float3 lighting, float probeValidity)
-{
-    const float3 finalRadiance = NormalizeOutputRadiance(lighting, probeValidity);
-    _RadianceCacheAxis[index] = finalRadiance;
+    return 1.0f - lerp(_LeakMultiplier, 0.0f, validity);
 }
 
-
 #endif // endof PROBE_PROPAGATION

com.unity.render-pipelines.high-definition/Runtime/Lighting/ProbeVolume/DynamicGI/ProbePropagationAxes.compute

@@ -259,7 +259,6 @@ void PropagateLight(uint3 id : SV_DispatchThreadID)
 
         float3 incomingHitRadiance = 0;
         float3 incomingMissRadiance = 0;
-        float probeValidity = 0;
         int neighborAxisIndexOffset = axisIndex * NEIGHBOR_AXIS_COUNT;
 
         BasisAxisHit basisAxisHit = ComputeBasisAxisHit(_RayAxis[axisIndex].xyz, _Sharpness);
@@ -275,7 +274,6 @@ void PropagateLight(uint3 id : SV_DispatchThreadID)
             uint hitIndex = 0;
             float probeAxisValidity = 0;
             UnpackIndicesAndValidityOnly(neighbor.hitIndexValidity, hitIndex, probeAxisValidity);
-            probeValidity += probeAxisValidity;
 
             BasisAxisHit basisAxisNeighborHit = ComputeBasisAxisHit(neighborAxisLookup.neighborDirection, _Sharpness);
 
@@ -307,7 +305,7 @@ void PropagateLight(uint3 id : SV_DispatchThreadID)
                         float3 prevAxisRadiance = ReadPreviousPropagationAxis(neighborProbeIndex, axisIndex);
 
                         float weight = neighborAxisLookup.propagationWeight;
-                        incomingMissRadiance += prevAxisRadiance * weight;
+                        incomingMissRadiance += prevAxisRadiance * weight * InvalidScale(probeAxisValidity);
                     #endif
                 }
 #if defined(SAMPLE_NEIGHBORS_DIRECTION_ONLY) || defined(SAMPLE_NEIGHBORS_POSITION_AND_DIRECTION)
@@ -338,9 +336,6 @@ void PropagateLight(uint3 id : SV_DispatchThreadID)
             }
         }
 
-        probeValidity *= 1.0 / PROPAGATION_AXIS_AMOUNT;
-
-        float3 lighting = (incomingHitRadiance + incomingMissRadiance) * _PropagationContribution;
-        WritePropagationOutput(index, lighting, probeValidity);
+        _RadianceCacheAxis[index] = (incomingHitRadiance + incomingMissRadiance) * _PropagationContribution;
     }
 }

com.unity.render-pipelines.high-definition/Runtime/Lighting/ProbeVolume/DynamicGI/ProbePropagationHits.compute

@@ -205,7 +205,7 @@ void AccumulateLightingDirectional(uint3 id : SV_DispatchThreadID)
         const SurfaceHitData hit = ConstructSurfaceHit(neighborData, worldPosition, probeVolumeLtw);
 
         #if defined(COMPUTE_INFINITE_BOUNCE)
-            float3 lighting = EstimateIncomingBounceLightAtHit(probeIndex, hit);
+            float3 lighting = EstimateIncomingBounceLightAtHit(probeIndex, hit) * InvalidScale(probeValidity);
         #else
             float3 lighting = 0;
         #endif
@@ -214,7 +214,6 @@ void AccumulateLightingDirectional(uint3 id : SV_DispatchThreadID)
 
         lighting += UnpackEmission(neighborData.emission) * _BakedEmissionMultiplier;
 
-        const float3 finalRadiance = NormalizeOutputRadiance(lighting, probeValidity);
-        _HitRadianceCacheAxis[hitAxisIndex] = finalRadiance;
+        _HitRadianceCacheAxis[hitAxisIndex] = lighting;
     }
 }

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

@@ -199,10 +199,9 @@ public ProbeVolumeDynamicGIStats GetStats()
             return _stats;
         }
 
-        internal static void AllocateNeighbors(ref ProbeVolumePayload payload, int numMissedAxis, int numHitAxis, int numAxis)
+        internal static void AllocateNeighbors(ref ProbeVolumePayload payload, int numHitAxis, int numAxis)
         {
-            int totalAxis = numMissedAxis + numHitAxis;
-            int totalProbes = totalAxis / s_NeighborAxis.Length;
+            int totalProbes = numAxis / s_NeighborAxis.Length;
             int totalProbeNeighborCapacity = (1 << 19);
             Debug.Assert(totalProbes < totalProbeNeighborCapacity);
 
@@ -211,14 +210,14 @@ internal static void AllocateNeighbors(ref ProbeVolumePayload payload, int numMi
         }
 
 
-        internal static void EnsureNeighbors(ref ProbeVolumePayload payload, int missedNeighborAxis, int hitNeighborAxis, int neighborAxis)
+        internal static void EnsureNeighbors(ref ProbeVolumePayload payload, int hitNeighborAxis, int neighborAxis)
         {
             if (payload.hitNeighborAxis == null
                 || payload.neighborAxis == null
                 || payload.hitNeighborAxis.Length != hitNeighborAxis
                 || payload.neighborAxis.Length != neighborAxis)
             {
-                AllocateNeighbors(ref payload, missedNeighborAxis, hitNeighborAxis, neighborAxis);
+                AllocateNeighbors(ref payload, hitNeighborAxis, neighborAxis);
             }
         }
 
@@ -289,10 +288,10 @@ private static uint PackAlbedoAndDistance(Vector3 color, float distance, float m
 
             uint packedOutput = 0;
 
-            packedOutput |= ((uint)(albedoR * 255.5f) << 0);
-            packedOutput |= ((uint)(albedoG * 255.5f) << 8);
-            packedOutput |= ((uint)(albedoB * 255.5f) << 16);
-            packedOutput |= ((uint)(normalizedDistance * 255.5f) << 24);
+            packedOutput |= (uint)(albedoR * 255f) << 0;
+            packedOutput |= (uint)(albedoG * 255f) << 8;
+            packedOutput |= (uint)(albedoB * 255f) << 16;
+            packedOutput |= (uint)(normalizedDistance * 255f) << 24;
 
             return packedOutput;
         }
@@ -324,8 +323,8 @@ private static uint PackIndexAndValidity(uint probeIndex, uint axisIndex, float
             uint output = 0;
 
             output |= axisIndex;
-            output |= (((uint)(validity * 255.5f) & 31) << 5);
-            output |= (probeIndex << 13);
+            output |= ((uint)(validity * 255f) & 255) << 5;
+            output |= probeIndex << 13;
 
             return output;
         }
@@ -335,8 +334,8 @@ private static uint PackIndexAndValidityOnly(uint probeIndex, float validity)
         {
             uint output = 0;
 
-            output |= (((uint)(validity * 255.5f) & 255) << 8);
-            output |= (probeIndex << 8);
+            output |= (uint)(validity * 255f) & 255;
+            output |= probeIndex << 8;
 
             return output;
         }

com.unity.render-pipelines.high-definition/Runtime/Lighting/ProbeVolume/DynamicGI/ProbeVolumeDynamicGI.hlsl

@@ -34,11 +34,11 @@ struct NeighborAxis
 float4 UnpackAlbedoAndDistance(uint packedVal, float maxNeighborDistance)
 {
     float4 outVal;
-    outVal.r = ((packedVal >> 0) & 255) / 255.5f;
-    outVal.g = ((packedVal >> 8) & 255) / 255.5f;
-    outVal.b = ((packedVal >> 16) & 255) / 255.5f;
+    outVal.r = ((packedVal >> 0) & 255) / 255.0f;
+    outVal.g = ((packedVal >> 8) & 255) / 255.0f;
+    outVal.b = ((packedVal >> 16) & 255) / 255.0f;
 
-    outVal.a = ((packedVal >> 24) & 255) / 255.5f;
+    outVal.a = ((packedVal >> 24) & 255) / 255.0f;
     outVal.a *= maxNeighborDistance * sqrt(3.0f);
 
     return outVal;

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

@@ -244,9 +244,8 @@ private void InitBakeNeighborData(ref ProbeBakeNeighborData bakeNeighborData)
         private void GeneratePackedNeighborData(ProbeBakeNeighborData[] neighborBakeDatas, ref ProbeVolumeAsset probeVolumeAsset, in ProbeVolumeArtistParameters parameters, int hits)
         {
             int totalAxis = neighborBakeDatas.Length * s_NeighborAxis.Length;
-            int missedAxis = totalAxis - hits;
-            EnsureNeighbors(ref probeVolumeAsset.payload, missedAxis, hits, totalAxis);
-
+            EnsureNeighbors(ref probeVolumeAsset.payload, hits, totalAxis);
+            
             float maxNeighborDistance = GetMaxNeighborDistance(in parameters);
             int missedAxisCount = 0;
             int hitAxisCount = 0;
@@ -261,17 +260,32 @@ private void GeneratePackedNeighborData(ProbeBakeNeighborData[] neighborBakeData
                     var emission = neighborBakeData.neighborEmission[axis];
                     var normal = neighborBakeData.neighborNormal[axis];
 
+                    var neighborPos = probeVolumeAsset.ComputePos3DFrom1D(i) + ProbeVolumeAsset.s_Offsets[axis];
+                    float neighborValidity;
+                    if (neighborPos.x >= 0 && neighborPos.y >= 0 && neighborPos.z >= 0
+                        && neighborPos.x < probeVolumeAsset.resolutionX
+                        && neighborPos.y < probeVolumeAsset.resolutionY
+                        && neighborPos.z < probeVolumeAsset.resolutionZ)
+                    {
+                        var neighborIndex = probeVolumeAsset.ComputeIndex1DFrom3D(neighborPos);
+                        neighborValidity = neighborBakeDatas[neighborIndex].validity;
+                    }
+                    else
+                    {
+                        neighborValidity = 0f;
+                    }
+
                     if (distance == 0)
                     {
                         // miss
-                        SetNeighborData(ref probeVolumeAsset.payload, validity, i, axis, NeighborAxis.Miss);
+                        SetNeighborData(ref probeVolumeAsset.payload, neighborValidity, i, axis, NeighborAxis.Miss);
                         ++missedAxisCount;
                     }
                     else
                     {
                         // hit
                         SetNeighborDataHit(ref probeVolumeAsset.payload, albedo, emission, normal, distance, validity, i, axis, hitAxisCount, maxNeighborDistance );
-                        SetNeighborData(ref probeVolumeAsset.payload, validity, i, axis, (uint)hitAxisCount);
+                        SetNeighborData(ref probeVolumeAsset.payload, neighborValidity, i, axis, (uint)hitAxisCount);
                         ++hitAxisCount;
                     }
                 }

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

@@ -151,6 +151,14 @@ protected internal int ComputeIndex1DFrom3D(Vector3Int pos)
             return pos.x + pos.y * resolutionX + pos.z * resolutionX * resolutionY;
         }
 
+        internal Vector3Int ComputePos3DFrom1D(int index)
+        {
+            return new Vector3Int(
+                index % resolutionX,
+                index / resolutionX % resolutionY,
+                index / (resolutionX * resolutionY));
+        }
+
         bool OverwriteInvalidProbe(ref ProbeVolumePayload payloadSrc, ref ProbeVolumePayload payloadDst, Vector3Int index3D, float backfaceTolerance)
         {
             int strideSHL01 = ProbeVolumePayload.GetDataSHL01Stride();