Path: utzoo!attcan!uunet!husc6!mailrus!uflorida!haven!umbc3!bodarky
From: bodarky@umbc3.UMD.EDU (Scott Bodarky)
Newsgroups: comp.graphics
Subject: Re: raytracing in ||
Message-ID: <1351@umbc3.UMD.EDU>
Date: 16 Nov 88 21:41:26 GMT
References: <9700001@datacube> <3148@uoregon.uoregon.edu>
Reply-To: bodarky@umbc3.UMD.EDU (Scott Bodarky)
Organization: University of Maryland, Baltimore County
Lines: 27

I am presently preparing to try and implement a ray tracer on an INMOS
transputer.  I've never done anything with ray tracing before, but I 
am starting to get a fairly clear picture of how it is done.  One good 
article I've read is "Exploiting concurrency: a ray tracing example"
by Jamie Packer, which is INMOS's Technical Note 7.  I do have some
questions I am hoping some of you out there might answer about
the algorithm itself.

1) Given a pixel on the screen, there are an infinite number of light
   rays that might hit it.  Does one only calculate the ray perpendicular
   to the screen, or is that insufficient?  How many rays does one
   calculate?

2) From an intersection point, one sends a test ray directly at the light
   sources to test for objects that might cast shadows.  What if you
   are on the far side of an object from a light source?  

Sorry if these are amateurish questions, but I'm new at (and intensely
interested in) this.

     -Scott Bodarky	          |	bodarky@umbc3 (UNIX)
				  |     bodarky@umbc2 (VMS)
				  |     bodarky@umbc1 (VMS)
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