al_set_new_bitmap_depth - Allegro 5 API

       Sets  the  depthbuffer  depth used by newly created bitmaps (on the current thread) if they are used with
       al_set_target_bitmap(3alleg5).  0 means no depth-buffer will be created when  drawing  into  the  bitmap,
       which is the default.

       al_set_new_bitmap_depth - Allegro 5 API

       5.2.1

              [UnstableAPI]: This is an experimental feature and currently only works for the OpenGL backend.

Allegro reference manual                                                        al_set_new_bitmap_depth(3alleg5)

              #include <allegro5/allegro.h>

              void al_set_new_bitmap_depth(int depth)
              SETTER(new_bitmap_depth, depth)