---
name: "request_video_bitmap"
section: "3alleg4"
platform: "linux"
package: "allegro4-doc"
version: "2:4.4.3.1-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/request_video_bitmap/3alleg4"
---

# request\_video\_bitmap(3alleg4)

Triple buffering page flip request. Allegro game programming library.

## 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)