public void move(int xa, int ya) {
		// this allows "sliding" on solid tile edges
		if(xa !=0 && ya != 0){
			move(xa, 0);
			move(0, ya);
			return;
		}
		// movement handling
		if (ya < 0)	dir = Direction.UP;
		if (ya > 0)	dir = Direction.DOWN;
		if (xa < 0)	dir = Direction.LEFT;
		if (xa > 0)	dir = Direction.RIGHT;

		if (!collision(xa, ya)) {
			x += xa;
			y += ya;
		}
	}