return (int) ((generateMask (1) & rgb[pixel]) >> (1 * pixel_bits));
return (0x0000FF00 & rgb[pixel]) >> 8;
  public final int getGreen (int pixel)  {    if (pixel < map_size)	    return (int) ((generateMask (1) & rgb[pixel]) >> (1 * pixel_bits));    			return 0;		}