Split Update of SH texture in several chunks to avoid allocations.

com.unity.render-pipelines.core/Runtime/Lighting/ProbeVolume/ProbeBrickPool.cs

@@ -7,7 +7,7 @@ namespace UnityEngine.Experimental.Rendering
 {
     internal class ProbeBrickPool
     {
-        const int kProbeIndexPoolAllocationSize = 64;
+        const int kProbeIndexPoolAllocationSize = 64; // 128;
 
         [DebuggerDisplay("Chunk ({x}, {y}, {z})")]
         public struct BrickChunkAlloc
@@ -123,7 +123,7 @@ internal void EnsureTextureValidity()
         }
 
         internal static int GetChunkSize() { return kProbeIndexPoolAllocationSize; }
-        internal int GetChunkSizeInProbeCount() { return kProbeIndexPoolAllocationSize * kBrickProbeCountTotal; }
+        internal static int GetChunkSizeInProbeCount() { return kProbeIndexPoolAllocationSize * kBrickProbeCountTotal; }
 
         internal int GetPoolWidth() { return m_Pool.width; }
         internal int GetPoolHeight() { return m_Pool.height; }
@@ -197,14 +197,12 @@ internal void Deallocate(List<BrickChunkAlloc> allocations)
                 m_FreeList.Push(brick);
         }
 
-        internal void Update(DataLocation source, List<BrickChunkAlloc> srcLocations, List<BrickChunkAlloc> dstLocations, ProbeVolumeSHBands bands)
+        internal void Update(DataLocation source, List<BrickChunkAlloc> srcLocations, List<BrickChunkAlloc> dstLocations, int destStartIndex, ProbeVolumeSHBands bands)
         {
-            Debug.Assert(srcLocations.Count == dstLocations.Count);
-
             for (int i = 0; i < srcLocations.Count; i++)
             {
                 BrickChunkAlloc src = srcLocations[i];
-                BrickChunkAlloc dst = dstLocations[i];
+                BrickChunkAlloc dst = dstLocations[destStartIndex + i];
 
                 for (int j = 0; j < kBrickProbeCountPerDim; j++)
                 {
@@ -342,16 +340,16 @@ static void SetPixel(DynamicArray<Color> data, int x, int y, int z, int dataLocW
             data[index] = value;
         }
 
-        public static void FillDataLocation(ref DataLocation loc, SphericalHarmonicsL2[] shl2, ProbeVolumeSHBands bands)
+        public static void FillDataLocation(ref DataLocation loc, SphericalHarmonicsL2[] shl2, int startIndex, int count, ProbeVolumeSHBands bands)
         {
             int numBricks = shl2.Length / kBrickProbeCountTotal;
-            int shidx = 0;
+            int shidx = startIndex;
             int bx = 0, by = 0, bz = 0;
             Color c = new Color();
 
             ValidateTemporaryBuffers(loc, bands);
 
-            for (int brickIdx = 0; brickIdx < shl2.Length; brickIdx += kBrickProbeCountTotal)
+            for (int brickIdx = startIndex; brickIdx < count && brickIdx < shl2.Length; brickIdx += kBrickProbeCountTotal)
             {
                 for (int z = 0; z < kBrickProbeCountPerDim; z++)
                 {
@@ -422,7 +420,7 @@ public static void FillDataLocation(ref DataLocation loc, SphericalHarmonicsL2[]
                     {
                         by = 0;
                         bz += kBrickProbeCountPerDim;
-                        Debug.Assert(bz < loc.depth || brickIdx == shl2.Length - kBrickProbeCountTotal, "Location depth exceeds data texture.");
+                        Debug.Assert(bz < loc.depth || brickIdx == count - kBrickProbeCountTotal, "Location depth exceeds data texture.");
                     }
                 }
             }

com.unity.render-pipelines.core/Runtime/Lighting/ProbeVolume/ProbeReferenceVolume.Debug.cs

@@ -287,9 +287,9 @@ void CreateInstancedProbes()
                 {
                     var brickSize = cell.bricks[i / 64].subdivisionLevel;
 
-                    int chunkIndex = i / m_Pool.GetChunkSizeInProbeCount();
+                    int chunkIndex = i / ProbeBrickPool.GetChunkSizeInProbeCount();
                     var chunk = chunks[chunkIndex];
-                    int indexInChunk = i % m_Pool.GetChunkSizeInProbeCount();
+                    int indexInChunk = i % ProbeBrickPool.GetChunkSizeInProbeCount();
                     int brickIdx = indexInChunk / 64;
                     int indexInBrick = indexInChunk % 64;
 

com.unity.render-pipelines.core/Runtime/Lighting/ProbeVolume/ProbeReferenceVolume.cs

@@ -284,7 +284,7 @@ public enum ProbeVolumeSHBands
     /// </summary>
     public partial class ProbeReferenceVolume
     {
-        const int kProbeIndexPoolAllocationSize = 128;
+        const int kTemporaryDataLocChunkCount = 8;
 
         [System.Serializable]
         internal class Cell
@@ -492,6 +492,7 @@ public struct RuntimeResources
 
         internal Dictionary<int, CellInfo> cells = new Dictionary<int, CellInfo>();
         ObjectPool<CellInfo> m_CellInfoPool = new ObjectPool<CellInfo>(x => x.Clear(), null, false);
+        ProbeBrickPool.DataLocation m_TemporaryDataLocation;
 
         internal ProbeVolumeSceneData sceneData;
 
@@ -1005,6 +1006,8 @@ void InitProbeReferenceVolume(ProbeVolumeTextureMemoryBudget memoryBudget, Probe
                 m_PositionOffsets[m_PositionOffsets.Length - 1] = 1.0f;
                 Profiler.EndSample();
 
+                m_TemporaryDataLocation = ProbeBrickPool.CreateDataLocation(kTemporaryDataLocChunkCount * ProbeBrickPool.GetChunkSizeInProbeCount(), compressed: false, m_SHBands, out var allocatedBytes);
+
                 m_ProbeReferenceVolumeInit = true;
 
                 ClearDebugData();
@@ -1068,6 +1071,7 @@ internal void Clear()
                 m_Pool.Clear();
                 m_Index.Clear();
                 cells.Clear();
+                m_TemporaryDataLocation.Cleanup();
             }
 
             if (clearAssetsOnVolumeClear)
@@ -1094,38 +1098,41 @@ bool AddBricks(CellInfo cellInfo, ProbeBrickIndex.CellIndexUpdateInfo cellUpdate
             if (!m_Pool.Allocate(brickChunksCount, cellInfo.chunkList))
                 return false;
 
-            // Create temporary allocation to copy SH data over to main atlas.
-            var dataloc = ProbeBrickPool.CreateDataLocation(cell.sh.Length, compressed: false, m_SHBands, out var allocatedBytes);
-            ProbeBrickPool.FillDataLocation(ref dataloc, cell.sh, m_SHBands);
-
-            // copy chunks into pool
-            m_TmpSrcChunks.Clear();
-            Chunk c;
-            c.x = 0;
-            c.y = 0;
-            c.z = 0;
-
-            // currently this code assumes that the texture width is a multiple of the allocation chunk size
-            for (int i = 0; i < cellInfo.chunkList.Count; i++)
+            int chunkIndex = 0;
+            while (chunkIndex < cellInfo.chunkList.Count)
             {
-                m_TmpSrcChunks.Add(c);
-                c.x += chunkSize * ProbeBrickPool.kBrickProbeCountPerDim;
-                if (c.x >= dataloc.width)
+                int chunkToProcess = Math.Min(kTemporaryDataLocChunkCount, cellInfo.chunkList.Count - chunkIndex);
+                ProbeBrickPool.FillDataLocation(ref m_TemporaryDataLocation, cell.sh, chunkIndex * ProbeBrickPool.GetChunkSizeInProbeCount(), chunkToProcess * ProbeBrickPool.GetChunkSizeInProbeCount(), m_SHBands);
+
+                // copy chunks into pool
+                m_TmpSrcChunks.Clear();
+                Chunk c;
+                c.x = 0;
+                c.y = 0;
+                c.z = 0;
+
+                // currently this code assumes that the texture width is a multiple of the allocation chunk size
+                for (int j = 0; j < chunkToProcess; j++)
                 {
-                    c.x = 0;
-                    c.y += ProbeBrickPool.kBrickProbeCountPerDim;
-                    if (c.y >= dataloc.height)
+                    m_TmpSrcChunks.Add(c);
+                    c.x += chunkSize * ProbeBrickPool.kBrickProbeCountPerDim;
+                    if (c.x >= m_TemporaryDataLocation.width)
                     {
-                        c.y = 0;
-                        c.z += ProbeBrickPool.kBrickProbeCountPerDim;
+                        c.x = 0;
+                        c.y += ProbeBrickPool.kBrickProbeCountPerDim;
+                        if (c.y >= m_TemporaryDataLocation.height)
+                        {
+                            c.y = 0;
+                            c.z += ProbeBrickPool.kBrickProbeCountPerDim;
+                        }
                     }
                 }
-            }
 
-            // Update pool textures with incoming SH data and ignore any potential frame latency related issues for now.
-            m_Pool.Update(dataloc, m_TmpSrcChunks, cellInfo.chunkList, m_SHBands);
+                // Update pool textures with incoming SH data and ignore any potential frame latency related issues for now.
+                m_Pool.Update(m_TemporaryDataLocation, m_TmpSrcChunks, cellInfo.chunkList, chunkIndex, m_SHBands);
 
-            dataloc.Cleanup();
+                chunkIndex += kTemporaryDataLocChunkCount;
+            }
 
             m_BricksLoaded = true;