debian man page for create_sub_zbuffer

create_sub_zbuffer(3alleg4)					  Allegro manual				       create_sub_zbuffer(3alleg4)

NAME
       create_sub_zbuffer - Creates a sub-z-buffer. Allegro game programming library.

SYNOPSIS
       #include <allegro.h>

       ZBUFFER *create_sub_zbuffer(ZBUFFER *parent, int x, int y, int width, int height);

DESCRIPTION
       Creates	a  sub-z-buffer,  ie. a z-buffer sharing drawing memory with a pre-existing z-buffer, but possibly with a different size. The same
       rules as for sub-bitmaps apply: the sub-z-buffer width and height can extend beyond the right and bottom edges of the parent (they will	be
       clipped), but the origin point must lie within the parent region.

       When  drawing z-buffered to a bitmap, the top left corner of the bitmap is always mapped to the top left corner of the current z-buffer. So
       this function is primarily useful if you want to draw to a sub-bitmap and use the corresponding sub-area of the z-buffer. In  other  cases,
       eg.  if	you just want to draw to a sub-bitmap of screen (and not to other parts of screen), then you would usually want to create a normal
       z-buffer (not sub-z-buffer) the size of the visible screen. You don't need to first create a z-buffer the size of the  virtual  screen  and
       then a sub-z-buffer of that.

RETURN VALUE
       Returns	the pointer to the sub ZBUFFER or NULL if there was an error.  Remember to destroy the ZBUFFER once you are done with it, to avoid
       having memory leaks.

SEE ALSO
       create_zbuffer(3alleg4), create_sub_bitmap(3alleg4), destroy_zbuffer(3alleg4)

Allegro 							   version 4.4.2				       create_sub_zbuffer(3alleg4)