cx = 16*(superchunk%12) + x/16; cy = 16*(superchunk/12) + y/16; tx = x%16; ty = y%16;
int cx = 16*(superchunk%12) + x/16, cy = 16*(superchunk/12) + y/16, tx = x%16, ty = y%16; return Tile_coord(cx*tiles_per_chunk + tx, cy*tiles_per_chunk + ty, 0);
	void get_pos(int& cx, int& cy, int& tx, int& ty)		{		cx = 16*(superchunk%12) + x/16;		cy = 16*(superchunk/12) + y/16;		tx = x%16;		ty = y%16;		}