.\" Generated by the Allegro makedoc utility
.TH request_video_bitmap 3alleg4 "version 4.4.3" "Allegro" "Allegro manual"
.SH NAME
request_video_bitmap \- Triple buffering page flip request. Allegro game programming library.\&
.SH SYNOPSIS
.B #include <allegro.h>

.sp
.B int request_video_bitmap(BITMAP *bitmap);
.SH 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:

.nf
   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;
   ...
.fi
.SH "RETURN VALUE"
Returns zero on success and non-zero on failure.

.SH SEE ALSO
.BR poll_scroll (3alleg4),
.BR request_scroll (3alleg4),
.BR gfx_capabilities (3alleg4),
.BR create_video_bitmap (3alleg4),
.BR scroll_screen (3alleg4),
.BR ex3buf (3alleg4),
.BR exupdate (3alleg4)