What are the main advantages of this method?  I have seen it described, and
the algiorithm seems a  little bit long.  I developed my own method, which
requires that the points be in a counter-clockwise order, and returns
whether you are looking at the back or the front, similar to the plane eqn
method.  It uses few calculations however, basically it is several
comparisons.  The only disadvantage I see is that it must be done after the
transformation from view coordinates to coordinates to display on the
screen, which means that a little more calculation isneeded beforehand.  My
method basically figures out whether the points that will appear on the
screen are clockwise or counterclockwise.  When looking at the back of
something, the points occur in an opposite direction from the front, so
merely by figuring out which way the points go, you can tell whether you are
looking at the back or front of a 2d polygon.  Has anyone heard of this
method before?  It is so simple, I doubt i am the first to think of it.

Libertarian, atheist, semi-anarchal Techno-Rat.