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From: blm@cxsea.UUCP (Brian Matthews)
Newsgroups: net.graphics
Subject: Re: Ray Trace problems
Message-ID: <875@cxsea.UUCP>
Date: Sun, 3-Aug-86 14:38:34 EDT
Article-I.D.: cxsea.875
Posted: Sun Aug  3 14:38:34 1986
Date-Received: Thu, 7-Aug-86 06:24:43 EDT
References: <220@joevax.UUCP>
Reply-To: blm@cxsea.UUCP (Brian Matthews)
Distribution: net
Organization: Computer X Inc.
Lines: 24

In article <220@joevax.UUCP> sdh@joevax.UUCP (The Doctor) writes:
|The ray tracer as posted dumps after doing 37.6% of the task,
|returning the error: floating point exception.

You might want to try commenting out the modification of vect->xzl in the
routine scamult in support.c. According to the author, this has given some
people problems, and xzl isn't used anywhere. I didn't have any problems
with the posted data, but when I moved the balls around, it died until I
removed the offending statement. It then generated some very nice output.

|Question: is the resolution of the output supposed to 450 x 450,
|and are the pixels supposed to be non-square?

The pixels are square, and the resolution is 451 x 451. Although it looks
like it goes from 100 to 250 by 1/3, .33333 etc. isn't quite 1/3, so there's
one extra pixel per line, and one extra line. Note that if you change INC in
tracer.c, it will change the resolution.

-- 

Brian L. Matthews
Computer X Inc. - a division of Motorola New Enterprises
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