man clear_zbuffer () - Writes a depth value into the given Z-buffer. Allegro game programming library.
NAME
clear_zbuffer - Writes a depth value into the given Z-buffer. Allegro game programming library.
SYNOPSIS
#include <allegro.h>
void clear_zbuffer(ZBUFFER *zbuf, float z);
DESCRIPTION
Writes z into the given Z-buffer (0 means far away). This function should be used to initialize the Z-buffer before each frame. Actually, low-level routines compare depth of the current pixel with 1/z: for example, if you want to clip polygons farther than 10, you must call clear_zbuffer(zbuf, 0.1).