Fixed negative chunks invisible

Renderer.cs

@@ -61,11 +61,12 @@ namespace Voxel
             if (_world == null) return;
 
             int offset = 0;
+
             foreach (Chunk chunk in _world.GetAllChunks())
             {
                 ChunkMesh chunkMesh = chunk.GetChunkMesh();
 
-                if (chunkMesh.NeedsUpdate)
+                if (chunkMesh.NeedsUpdate) // always true
                 {
                     byte[] data = chunkMesh.GetPackedData();
                     GL.BufferSubData(BufferTarget.ShaderStorageBuffer, (IntPtr)offset * 8, chunkMesh.Size * 8, data);