Path: utzoo!utgpu!attcan!uunet!lll-winken!lll-tis!ames!mailrus!uflorida!gatech!bloom-beacon!tut.cis.ohio-state.edu!spencer
From: spencer@tut.cis.ohio-state.edu (Stephen Spencer)
Newsgroups: comp.graphics
Subject: Re: Vectorizing ray-object intersection calculations
Summary: there's some work been done..
Keywords: ray tracing, vectorization
Message-ID: <20813@tut.cis.ohio-state.edu>
Date: 26 Aug 88 17:55:15 GMT
References: <594@fcs280s.ncifcrf.gov>
Organization: Ohio State Computer & Info Science
Lines: 23

In article <594@fcs280s.ncifcrf.gov>, palmer@ncifcrf.gov (Thomas Palmer) writes
> 
> Has anyone done any work on vectorizing ray-object intersection
> calculations? 

There was an article in IEEE CG&A about four years ago about vectorizing
ray-sphere intersections on a Cyber which included an algorithmic workup 
of how it worked.

As far as ray-polygon intersection goes, the article in SIGGRAPH '87 dealing
with tesselation of polygonal objects (it had the pictures of grass and the
Statue of Liberty in it) included the algorithm for fast ray-polygon 
intersection, and I did implement it and it did vectorize quite nicely. 
I unfortunately no longer seem to have that piece of code, but it wasn't 
difficult.  Of course you still have to do the sorting of the intersection
points but the heavy intersection calculations can be done quickly.



-- 
Stephen Spencer
Advanced Computing Center for the Arts and Design (ACCAD)
The Ohio State University               | spencer@hardy.cgrg.ohio-state.edu
1224 Kinnear Road, Columbus OH 43212    | spencer@tut.cis.ohio-state.edu