bionic (3) scene_gap.3alleg4.gz

NAME

       scene_gap - Number controlling the scene z-sorting algorithm behaviour. Allegro game programming library.

SYNOPSIS

       #include <allegro.h>

       extern float scene_gap;

DESCRIPTION

       This  number  (default  value = 100.0) controls the behaviour of the z-sorting algorithm. When an edge is
       very close to another's polygon plane, there is an interval of uncertainty in which you cannot tell which
       object  is  visible  (which z is smaller). This is due to cumulative numerical errors for edges that have
       undergone a lot of transformations and interpolations.

       The default value means that if the 1/z values (in projected space) differ by only 1/100  (one  percent),
       they  are  considered  to  be  equal  and  the x-slopes of the planes are used to find out which plane is
       getting closer when we move to the right.

       Larger values means narrower margins, and increasing the chance of missing  true  adjacent  edges/planes.
       Smaller  values  means larger margins, and increasing the chance of mistaking close polygons for adjacent
       ones.  The value of 100 is close to the optimum. However, the optimum shifts  slightly  with  resolution,
       and may be application-dependent. It is here for you to fine-tune.

SEE ALSO

       create_scene(3alleg4),      clear_scene(3alleg4),      destroy_scene(3alleg4),     render_scene(3alleg4),
       scene_polygon3d(3alleg4)