erasing sections of a bitmap

no-reply@allegro.cc (KirbyDS11) — Wed, 26 Jun 2013 23:51:57 +0000

Hi
I was wondering how you would erase a circle or a rectangle out of a bitmap.

#SelectExpand
 1if(al_is_bitmap_locked(land))
 2{
 3    al_unlock_bitmap(land);
 4}
 5al_set_target_bitmap(land);
 6al_draw_filled_circle(centerx,centery,radius,al_map_rgba(0,0,0,0));
 7al_set_target_bitmap(al_get_backbuffer(display));

this does not work but would it be something similar to this but with something else added in?

no-reply@allegro.cc (SiegeLord) — Thu, 27 Jun 2013 00:10:26 +0000

Something like this should work:

al_set_blender(ALLEGRO_ADD, ALLEGRO_ONE, ALLEGRO_ZERO);
al_draw_filled_circle(centerx,centery,radius,al_map_rgba(0,0,0,0));
al_set_blender(ALLEGRO_ADD, ALLEGRO_ONE, ALLEGRO_INVERSE_ALPHA);

no-reply@allegro.cc (KirbyDS11) — Thu, 27 Jun 2013 00:14:00 +0000

Yep it worked
Thank you