al_set_new_bitmap_samples man page

al_set_new_bitmap_samples — Allegro 5 API

Synopsis

#include <allegro5/allegro.h>

void al_set_new_bitmap_samples(int samples)
SETTER(new_bitmap_samples, samples)

Description

Sets the multi-sampling samples used by newly created bitmaps (on the current thread) if they are used with al_set_target_bitmap(3). 0 means multi-sampling will not be used when drawing into the bitmap, which is the default. 1 means multi-sampling will be used but only using a single sample per pixel (so usually there will be no visual difference to not using multi-sampling at all).

Note: Some platforms have restrictions on when the multi-sampling buffer for a bitmap is realized, i.e. down-scaled back to the actual bitmap dimensions. This may only happen after a call to al_set_target_bitmap(3). So for example:

al_set_target_bitmap(multisample);
al_clear_to_color(blue);
al_draw_line(0, 0, 100, 100, red, 1);
al_lock_bitmap(multisample, ...)
// ERROR: the contents of the bitmap will be undefined

al_set_target_bitmap(backbuffer);
al_lock_bitmap(multisample, ...)
// CORRECT: at this point, the bitmap contents are updated and
// there will be an anti-aliased line in it.

Since

5.2.1

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

Referenced By

al_get_new_bitmap_samples(3).

Allegro reference manual