al_get_backbuffer(3)

💖 NAME 💖

hii bestie, welcome to the al_get_backbuffer(3) page — this is the Library Functions Manual entry for the Allegro 5 API. The function is al_get_backbuffer, and it is literally about getting the display’s back-buffer bitmap 🫶

🌸 SYNOPSIS 🌸

#include <allegro5/allegro.h>

ALLEGRO_BITMAP *al_get_backbuffer(ALLEGRO_DISPLAY *display)

🦋 DESCRIPTION 🦋

So this function returns a special bitmap that represents the back-buffer of the display ✨ It’s giving “main character bitmap”, but it’s special, okay? 👑

Care should be taken when using the backbuffer bitmap (and its sub-bitmaps) as the source bitmap (e.g as the bitmap argument to al_draw_bitmap(3)) 🙈 This is the part where you gotta pay attention, bestie.

Only untransformed operations are hardware accelerated. These consist of al_draw_bitmap(3) and al_draw_bitmap_region(3) when the current transformation is the identity 💅 If the transformation is not the identity, or some other drawing operation is used, the call will be routed through the memory bitmap routines, which are slow 😭 No cap.

If you need those operations to be accelerated, then first copy a region of the backbuffer into a temporary bitmap (via the al_draw_bitmap(3) and al_draw_bitmap_region(3)), and then use that temporary bitmap as the source bitmap 🎀 That’s the move. Periodt.

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That’s the whole page, bestie: it’s from the Allegro reference manual, and the page is al_get_backbuffer(3) — no date printed on this one, just the manual source and title doing their little sign-off 💖🦋