man set_difference_blender () - Enables a difference blender mode. Allegro game programming library.
NAME
set_difference_blender - Enables a difference blender mode. Allegro game programming library.
SYNOPSIS
#include <allegro.h>
void set_difference_blender(int r, int g, int b, int a);
DESCRIPTION
Enables a difference blender mode for combining translucent or lit truecolor pixels. This makes an image which has colours calculated by the difference between the source and destination colours.