changed some rendering buffer code

Renderer.cs

@@ -60,20 +60,24 @@ namespace Voxel
         {
             if (_world == null) return;
 
-            int offset = 0;
+            _chunkBufferSizes.Clear();
+            int faceOffset = 0;
 
             foreach (Chunk chunk in _world.GetAllChunks())
             {
                 ChunkMesh chunkMesh = chunk.GetChunkMesh();
 
-                if (chunkMesh.NeedsUpdate) // always true
-                {
-                    byte[] data = chunkMesh.GetPackedData();
-                    GL.BufferSubData(BufferTarget.ShaderStorageBuffer, (IntPtr)offset * 8, chunkMesh.Size * 8, data);
-                }
+                _chunkBufferSizes[(chunk.X, chunk.Y)] = faceOffset;
 
-                _chunkBufferSizes[(chunk.X, chunk.Y)] = offset;
-                offset += chunkMesh.Size * 8;
+                byte[] data = chunkMesh.GetPackedData();
+
+                GL.BufferSubData(BufferTarget.ShaderStorageBuffer,
+                    (IntPtr)(faceOffset * 8),  // faceOffset * 8 = byte offset
+                    chunkMesh.Size * 8,
+                    data
+                );
+
+                faceOffset += chunkMesh.Size;
             }
         }