set_burn_blender - Man Page

#include <allegro.h>

void set_burn_blender(int r, int g, int b, int a);

Enables a burn blender mode for combining translucent or lit truecolor  pixels. Here the lightness values of the colours of the source image  reduce the lightness of the destination image, darkening the image.

set_trans_blender(3), drawing_mode(3)

set_trans_blender(3).