That's the old "magic pink", which was traditionally used as a mask colour.

In A5 you will need to call:

al_convert_mask_to_alpha(your_bitmap, al_map_rgb(255, 0, 255));

Where "your_bitmap" is the ALLEGRO_BITMAP* you want to create alpha for. That will turn the pink into an alpha channel.

If it is a file you're loading then do what I do.

Open it in a paint program that can manipulate the alpha channel. Set the alpha value of the pink pixels to 0 and save it.

May have to convert to another format, not sure. I use .png for all my bitmap files.

If not then yes, this is what you do:

al_convert_mask_to_alpha(your_bitmap, al_map_rgb(255, 0, 255));

Only sets the alpha channel to 0. Doesn't change the r, g or b.

al_convert_mask_to_alpha
This function just converts every pixel that matches the color and sets the alpha channel to 0.

Either do it manually pre-load like I do or post-load with al_convert_mask_to_alpha.

Gotcha, so basically building the
al_convert_mask_to_alpha(your_bitmap, al_map_rgb(255, 0, 255));
into the picture. Thanks.

Thanks Edgar. I thought pink was the only color it would work with. Didn't realize you could use other colors. Thanks