added (optional) array of surface types, so that each triangle can have a different appearance
added (optional) array of surface types, so that each triangle can have a different appearance

markraz/vtp,seanisom/vtp,nakijun/vtp,nakijun/vtp,nakijun/vtp,markraz/vtp,nakijun/vtp,markraz/vtp,nakijun/vtp,seanisom/vtp,markraz/vtp,seanisom/vtp,markraz/vtp,seanisom/vtp,seanisom/vtp