From: thinman@netcom.com (Lance Norskog)
Subject: Re: TECH: More on object collisions
Date: Thu, 27 Feb 92 20:40:34 PST



Since the sphere-collision test is the fastest, what we want is
a sphere-packing method that is recursive.  That is, an interesting
number of packed spheres form a larger sphere and the outermost
packed spheres all touch the larger sphere.  This would serve to
be a fast pruning system for finding finer checks.  The world is
then subdivided into a tree of empty and occupied spheres; from
there on it's the same as with an octree-based collider.

About combining the collider with the occluder: the collider has
to do everything, not just the stuff you see, but it doesn't really
need to check polygon interpenetration, does it?  You don't want
funky physics to happen behind your back like giant boxes 
sliding through each other, but minor stuff is OK.
The screen can be updated when the visual area has been fully
processed, but stuff outside the visual range can be done
after the screen is painted.  However, the sound has to be updated after all
the collisions are processed, and so it should be finished by the time
the corresponding screen appears.  So there's a little scheduling
flexibility here.

Lance Norskog