al_set_bitmap_blender - Allegro 5 API

       Sets  the  function  to use for blending when rendering to the target bitmap.  If no blender is set for a
       given bitmap at draw time, the values  set  for  al_set_blender(3alleg5)/al_set_separate_blender(3alleg5)
       are used instead.

       To     use     separate     functions     for     chroma     (RGB)     and     alpha     channels,    use
       al_set_separate_bitmap_blender(3alleg5).

       See al_set_blender(3alleg5) for more information about how blending works.

       al_set_bitmap_blender - Allegro 5 API

al_set_separate_bitmap_blender(3alleg5), al_reset_bitmap_blender(3alleg5)

       5.2.5

              [UnstableAPI]: New API.

Allegro reference manual                                                          al_set_bitmap_blender(3alleg5)

              #include <allegro5/allegro.h>

              void al_set_bitmap_blender(int op, int src, int dest)