[net.graphics] ray tracing

sugtech@lll-lcc.UUcp (SUG Tech Committee) (02/15/86)

I am working on a masters thesis at Brigham Young University.  The
subject of my thesis is ray tracing, and I need some ray tracing source code.
Just a listing will do.  The code must not be proprietary in any form, and
it doesn't matter if it's simple or complex.  A Whitted algorithm would be 
tandy and a distributed ray tracing algorithm would be super.  If anyone can
help, please give me a "ring".

Ernie Pyle

lll-lcc!sugtech@lll-crg.arpa  

ugsudy@sunybcs.UUCP (Sudhakar Bharadwaj) (07/16/86)

    I saw a few articles on Ray Tracing.  I am trying to implement
Ray Tracing algorithms on 4 Mercury Zip 32016 Array Processors
connected to a Unix Machine with 5 MC68000's.  The intersection
algorithms will be run on the Mercurys and user I/O, Communications,
and display will be run on the 68000's.  Basically, I will do 1
scanline at a time, checking for intersections, calculations shading,
reflection and refraction values inside the mercurys.  I am planning
to have 1 mercury for preliminary calculations for the intersections,
another for the intersections (maybe even the third one also, or 
maybe the third for cleaning up - shading/reflection/refraction) and
the  fourth for any final calculations (if I can get around to it,
the fourth one will have a frame buffer attached to an auxliary
port of the mercury and the image will be displayed upon completion
of each scanline, that will save the time of trasnfering 1 scanline
of pixel information back to the 68000's).

	Vectorizing Ray Tracing is not that bad, once you know
that you are tracing 1024 x 1024 rays with 1 particular
object, so that the same intersection algorithm can be run.

	This subject does seem to provoke more interest then I
thought it would.  Does anyone out there have any benchmark
figures to show how much a reduction in time an algorithm using
an array processor yields?  

fritzz@net1.UCSD.EDU (Friedrich Knauss) (08/07/86)

It's back, and it's better. There were several of you who sent me mail
asking for the last refraction update (about 80 or so), so I figured
that this would be worth doing right.

I just posted tracer version 2.0 net net.sources, and it is a definite
improvement over version 1.0. It isn't very compatible with version one
either, which is why I chose to repost the whole shebang. 

None of the problems that were around in the old one should be in the
new one (I hope), and the code should run a little faster except for the
refraction routines which are doubly recursive and very long.
(with lots of sqrts and other nasty stuff).

It is still meant to be a hackers toy, so feel free to go in and chew it
up. If there are any people you know of that want it but aren't on the
net please feel free to pass it on.

As usual, post good comments to net graphics, and send all suggestions,
comments and requests to (fritzz@net1 || ...sdcsvax!net1!fritzz)

f

nwh@gec-rl-hrc.co.uk (Nigel Holder Marconi) (08/08/86)

would some kind sole please post via email  (or whatever) parts
1 and 2 of the ray tracing C program.  Thanks in advance ..


Nigel Holder			UK JANET:       yf21@uk.co.gec-mrc.u
Marconi Research,		ARPA:           yf21%u.gec-mrc.co.uk@ucl-cs
Chelmsford,
Essex. CM2 8HN.

+44 245 73331   ext. 3219 / 3214