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)