RE: [Algorithms] Strips

[Charles B. <cb...@cb...>]

At 10:36 AM 8/17/2000 +0100, you wrote:
>I have a bit of a knee-jerk response to strips, because of their
>worse-than-list vertex caching (up to twice as bad). However, since normal
>VIPM pretty much destroys the vertex cache anyway, this argument doesn't
>hold much water!

I don't understand why you say strips have a worse cache behaviour than
lists.  At the very worst, I can always make a strip which is identical to
a given list.

The list (abc)(def)... 
is the strip (abccddef...)

Which has identical vertex cache behaviour.  Given, that's not such a hot
thing to do, but when you optimize for vertex cache, you will in general
be generating lots of rectangular grids of triangles in your triangle list,
and those can be stripped neatly.

Hence, I can write a new stripper which simply optimizes the tri-list for
vertex cache and then tries to strip the resulting triangle list by building
the "brute force" strip I describe above, but collapse the uneccessary
duplicated vertex indices when possible.  I conjecture that on typical
meshes, you'd end up with a (maybe small) saving in the number of indices
by using strips, and get (nearly) identical vertex cache behaviour.

--------------------------------------
Charles Bloom           www.cbloom.com