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).
SEE ALSO
       create_zbuffer(3alleg),  set_zbuffer(3alleg),  destroy_zbuffer(3alleg),
       exzbuf(3alleg)