Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!labrea!rutgers!mcnc!rti!tachyon!sch
From: sch@tachyon.UUCP (Steve Holzworth)
Newsgroups: comp.graphics
Subject: Bug in Mark's RayTracer
Keywords: raytracer bug
Message-ID: <190@tachyon.UUCP>
Date: 30 Sep 88 07:07:32 GMT
Organization: William G. Daniel & Associates, Cary, N.C.
Lines: 20


There is a bug in the screen.c routine of Mark's raytracer.
Specifically, everywhere he does a malloc, the code is of the form:

foo = (Pixel *) malloc (xres * sizeof (Pixel)) + 1;

The actual intent is to allocate xres+1 Pixels, thusly:

foo = (Pixel *) malloc ((xres + 1) * sizeof (Pixel));

There are three occurences of the former in the code; they should be changed
similarly to the later.  (Note: I never ran over this bug until I tried
to run a 1024x1024 image.  It worked fine on 512x512 or less images.)

Other than that, its a good raytracer.  Congrats, Mark!  I'm working on
a better lighting model and a better camera model.  I'll send them on 
when (if) I finish them.

						Steve Holzworth
						rti!tachyon!sch