man _getpixel () - Faster specific version of getpixel(). Allegro game programming library.
NAME
_getpixel, _getpixel15, _getpixel16, _getpixel24, _getpixel32 - Faster specific version of getpixel(). Allegro game programming library.
SYNOPSIS
#include <allegro.h>
int _getpixel(BITMAP *bmp, int x, int y);
int _getpixel15(BITMAP *bmp, int x, int y);
int _getpixel16(BITMAP *bmp, int x, int y);
int _getpixel24(BITMAP *bmp, int x, int y);
int _getpixel32(BITMAP *bmp, int x, int y);
DESCRIPTION
Faster inline versions of getpixel() for specific color depths. These won't work in mode-X, and don't do any clipping, so you must make sure the point lies inside the bitmap.
RETURN VALUE
Returns the value of the pixel in the color format you specified.