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request_video_bitmap(3)		Allegro	manual	       request_video_bitmap(3)

NAME
       request_video_bitmap - Triple buffering page flip request. Allegro game
       programming library.

SYNOPSIS
       #include	<allegro.h>

       int request_video_bitmap(BITMAP *bitmap);

DESCRIPTION
       This function is	used for triple	buffering. It requests a page flip  to
       display	the  specified	video  bitmap  object, but returns immediately
       rather than waiting for a retrace. The flip will	then take place	during
       the  next  vertical retrace, but	you can	carry on running other code in
       the meantime and	use the	poll_scroll() routine to detect	when the  flip
       has  actually taken place. Triple buffering is only possible on certain
       hardware: see the comments about	request_scroll(). Example:

	  int current_page;
	  BITMAP *video_page[3];
	  ...
	  /* Create pages for page flipping */
	  video_page[0]	= create_video_bitmap(SCREEN_W,	SCREEN_H);
	  video_page[1]	= create_video_bitmap(SCREEN_W,	SCREEN_H);
	  video_page[2]	= create_video_bitmap(SCREEN_W,	SCREEN_H);
	  current_page = 0;
	  ...
	  /* draw the screen and flip pages */
	  draw_screen(video_page[current_page]);
	  do {
	  } while (poll_scroll());
	  request_video_bitmap(video_page[current_page]);
	  current_page = (current_page+1)%3;
	  ...

RETURN VALUE
       Returns zero on success and non-zero on failure.

SEE ALSO
       poll_scroll(3),	  request_scroll(3),	 gfx_capabilities(3),	  cre-
       ate_video_bitmap(3), scroll_screen(3), ex3buf(3), exupdate(3)

Allegro				 version 4.4.2	       request_video_bitmap(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO

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