request_video_bitmap(3alleg4)					  Allegro manual				     request_video_bitmap(3alleg4)

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(3alleg4),	request_scroll(3alleg4),    gfx_capabilities(3alleg4),	  create_video_bitmap(3alleg4),    scroll_screen(3alleg4),
       ex3buf(3alleg4), exupdate(3alleg4)

Allegro 							   version 4.4.2				     request_video_bitmap(3alleg4)