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From: hollasch@ENUXHA.EAS.ASU.EDU (Steve Hollasch)
Newsgroups: comp.graphics
Subject: How do YOU compute refraction vectors?
Summary: *I* compute them incorrectly.  =^/
Message-ID: <9105270128.AA16638@enuxha.eas.asu.edu>
Date: 27 May 91 01:28:50 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: hollasch@enuxha.eas.asu.edu (Steve Hollasch)
Organization: Arizona State University
Lines: 21


    Well, it's time for my netwide self-abasement.  As some people have
pointed out (thanks Juhana and Colm), the nifty wonderful and
oh-so-efficient method I posted last week is also oh-so-incorrect.  (sigh)

    It turns out that I was using the lesser-know Snell's Dog's Law:

                                   n1
                         tan(A1) = -- tan(A2)
                                   n2

    In my defense, I got the formula from class notes that were themselves
incorrect, but I have to confess that I duplicated the error while driving
through the derivation.

    So, please ignore (I think most people already have, thankfully) my
last post about refraction vector calculation.

______________________________________________________________________________
Steve Hollasch                /      Arizona State University (Tempe, Arizona)
hollasch@enuxha.eas.asu.edu  /  uunet!mimsy!oddjob!noao!asuvax!enuxha!hollasch