1al_get_backbuffer(3)                                      al_get_backbuffer(3)
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NAME

6       al_get_backbuffer - Allegro 5 API
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SYNOPSIS

9              #include <allegro5/allegro.h>
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11              ALLEGRO_BITMAP *al_get_backbuffer(ALLEGRO_DISPLAY *display)
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DESCRIPTION

14       Return a special bitmap representing the back-buffer of the display.
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16       Care should be taken when using the backbuffer bitmap (and its sub-bit‐
17       maps) as the source bitmap (e.g as the bitmap argument to  al_draw_bit‐
18       map(3)).   Only  untransformed  operations  are  hardware  accelerated.
19       These consist of al_draw_bitmap(3)  and  al_draw_bitmap_region(3)  when
20       the  current  transformation  is the identity.  If the tranformation is
21       not the identity, or some other drawing operation  is  used,  the  call
22       will  be routed through the memory bitmap routines, which are slow.  If
23       you need those operations to be accelerated, then first copy  a  region
24       of  the  backbuffer  into a temporary bitmap (via the al_draw_bitmap(3)
25       and al_draw_bitmap_region(3)), and then use that  temporary  bitmap  as
26       the source bitmap.
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30Allegro reference manual                                  al_get_backbuffer(3)
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