Assets/Features/VoxelWorld/Runtime/VoxelWorldGenerator.cs

@@ -281,9 +281,11 @@ namespace InfiniteWorld.VoxelWorld
                     continue;
                 }
 
+                Vector2Int regionCoord = ChunkToRegion(coord);
                 MarkRegionDirty(coord);
                 chunks.Remove(coord);
                 runtime.Dispose();
+                TryDisposeRegionIfEmpty(regionCoord);
                 QueueNeighborRefresh(coord);
             }
         }
@@ -510,7 +512,16 @@ namespace InfiniteWorld.VoxelWorld
                             continue;
                         }
 
-                        RegionBuildResult result = await UniTask.RunOnThreadPool(() => BuildRegionBuffers(request));
+                        RegionBuildResult result = request.Chunks == null || request.Chunks.Length == 0
+                            ? RegionBuildResult.CreateEmpty(request.RegionCoord, request.Version, request.Session)
+                            : await UniTask.RunOnThreadPool(() => BuildRegionBuffers(request));
+
+                        if (!IsRegionBuildStillCurrent(result.RegionCoord, result.Version, result.Session))
+                        {
+                            buildsThisFrame++;
+                            continue;
+                        }
+
                         lock (regionBuildLock)
                         {
                             completedRegionBuilds.Enqueue(result);
@@ -568,6 +579,53 @@ namespace InfiniteWorld.VoxelWorld
             return true;
         }
 
+        private bool IsRegionBuildStillCurrent(Vector2Int regionCoord, int version, int session)
+        {
+            if (session != generationSession)
+            {
+                return false;
+            }
+
+            regionVersions.TryGetValue(regionCoord, out int currentVersion);
+            return version == currentVersion;
+        }
+
+        private void TryDisposeRegionIfEmpty(Vector2Int regionCoord)
+        {
+            if (RegionHasVisibleChunks(regionCoord))
+            {
+                return;
+            }
+
+            if (regions.TryGetValue(regionCoord, out RegionRuntime region))
+            {
+                region.Dispose();
+                regions.Remove(regionCoord);
+            }
+
+            regionVersions.Remove(regionCoord);
+        }
+
+        private bool RegionHasVisibleChunks(Vector2Int regionCoord)
+        {
+            Vector2Int baseChunk = new Vector2Int(regionCoord.x * renderRegionSizeInChunks, regionCoord.y * renderRegionSizeInChunks);
+            for (int z = 0; z < renderRegionSizeInChunks; z++)
+            {
+                for (int x = 0; x < renderRegionSizeInChunks; x++)
+                {
+                    Vector2Int chunkCoord = new Vector2Int(baseChunk.x + x, baseChunk.y + z);
+                    if (!chunks.TryGetValue(chunkCoord, out ChunkRuntime runtime) || runtime.RenderSnapshot == null || runtime.RenderSnapshot.IsEmpty)
+                    {
+                        continue;
+                    }
+
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
         private Vector2Int ChunkToRegion(Vector2Int chunkCoord)
         {
             return new Vector2Int(