erasing sections of a bitmap

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erasing sections of a bitmap

KirbyDS11

Member #15,167

June 2013

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?

Woops

SiegeLord

Member #7,827

October 2006

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);

"For in much wisdom is much grief: and he that increases knowledge increases sorrow."-Ecclesiastes 1:18
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KirbyDS11

Member #15,167

June 2013

Yep it worked
Thank you

Woops