public final int getAlpha(int pixel) { if (pixel < map_size) { return ((rgb[pixel] >> 24) & 0xFF); } else {
public final int getAlpha (int pixel) { if (pixel < map_size) return (int) ((generateMask (3) & rgb[pixel]) >> (3 * pixel_bits));
	public final int getAlpha(int pixel) {		if (pixel < map_size) {			return ((rgb[pixel] >> 24) & 0xFF);		} else {			return 0;		}	}