&gt; <i>code that deal with geometry data shouldn&#x27;t really be any different for games</i><p>Counter-example: <a href="http:&#x2F;&#x2F;jonathanwhiting.com&#x2F;games&#x2F;knossu&#x2F;" rel="nofollow">http:&#x2F;&#x2F;jonathanwhiting.com&#x2F;games&#x2F;knossu&#x2F;</a> (Highly recommended if you have 20 minutes to spare.) The geometry of this game is unlike <i>any</i> I have seen so far.  There is common logic with that of a Doom-like ray caster, but I&#x27;d argue not much.  The time spent rewriting the generic parts of a ray caster probably pales in comparison to the specific parts of his graphics engine.<p>(Of course, your point stands in general. But for Jonathan Whiting in particular, I have the feeling that it may not.)