Palette Swapping in Allegro 5

Question

I am trying to do a palette swap in Allegro 5. I have not found any way to do this from my research. So what I've thought of doing is to do it myself by setting individual pixels. I also haven't found a way to do this but Allegro 5 does allow for getting pixels. Is there some way to set a pixel in Allegro 5?

Answer 1

I'm not familiar with Allegro, but a scan through the documentation turns up the following:

al_draw_pixel
void al_draw_pixel(float x, float y, ALLEGRO_COLOR color)

Draws a single pixel at x, y.

al_put_pixel
void al_put_pixel(int x, int y, ALLEGRO_COLOR color)

Draw a single pixel on the target bitmap.

If you look at the source code linked from the documentation of either, you will notice that both make a call to al_get_target_bitmap, which is used to get the target bitmap of the calling thread. That function has a setter companion: al_set_target_bitmap which is used to select the bitmap to which all subsequent drawing operations in the calling thread will draw (docs for the latter).

For performance reasons, you might also want to look into locking the bitmap with al_lock_bitmap when manipulating the pixels.

There also appears to be some example code with some manual palette manipulation.