[comp.graphics] Dark 'gears' output from Mark VandeWettering's raytracer

musashi@chinet.UUCP (Irving Moy) (09/13/88)

Hi folks!!!

	I have Mark VandeWettering's raytracer running on a Sun 3/260
and Version 2.4 of Eric Haines' SPD (I took the SPD that Mark posted and
applied the patch that Eric posted to get Ver. 2.4).  I display the output
of the raytracer on a Targa 32; I had to add an extra byte in the output
file for the Targa's alpha channel.  The output of 'balls.c' looks great;
I now have my very own "sphereflake"!!!
	I tried 'gears' at a size factor of 4 and the resulting output is
quite dark.  The background is a nice UNC blue but the gear surfaces are
very dark and so is the reflecting polygon underneath the gears.
Has anyone else tried to raytrace 'gears' with Mark's program yet???
Enquiring minds want to know.....(BTW, if you look closely at 'sphereflake',
you can see Elvis (recursively, of course)).


				Irv Moy
				UUCP: ..!chinet!musashi
				Internet: musashi@chinet.uucp
DISCLAIMER: "If I knew what I was doing, I'd be dangerous."

ronbo@vixen.uucp (Ron Hitchens) (09/14/88)

In article <6574@chinet.UUCP> musashi@chinet.UUCP (Irving Moy) writes:
>	I tried 'gears' at a size factor of 4 and the resulting output is
>quite dark.  The background is a nice UNC blue but the gear surfaces are
>very dark and so is the reflecting polygon underneath the gears.
>Has anyone else tried to raytrace 'gears' with Mark's program yet???
>Enquiring minds want to know.....

   This may have some bearing on the problem:

vixen% ray -i gears.nff -o gears.pic -t
ray: (9345 prims, 5 lights)
ray: inputfile = "gears.nff"
ray: resolution 512 512
ray: after adding bounding volumes, 10516 prims
				    ^^^^^

   From defs.h:

#define MAXPRIMS        (10000)
			 ^^^^^

   I ran gears.nff last night and got the same results.  I bumped MAXPRIMS to
11000 and ran it again, seemed to work fine.  I only ran a 128x128 version,
the resolution was so low that most of the gears looked like fuzzy blobs, but
it seemed to be properly lighted and plenty colorful.  I have a 512x512 run
going now, should be finished in about 12 hours (I love my Sun 3/60FC, but it
sure would be handy to have a Cray now and then).

> (BTW, if you look closely at 'sphereflake',
> you can see Elvis (recursively, of course)).

   Naw, that's the spirit of Tom Snyder, Elvis is way too busy channelling
through an unemployed truck driver in Muncie, Indiana.

   To Mark VandeWettering: Hey, thanks for the ray tracer.  I don't suppose
you could send me a disk drive to store all these picture files on could you?

Ron Hitchens		ronbo@vixen.uucp	hitchens@cs.utexas.edu

markv@uoregon.uoregon.edu (Mark VandeWettering) (09/15/88)

In article <251@vixen.uucp> ronbo@vixen.UUCP (Ron Hitchens) writes:
>In article <6574@chinet.UUCP> musashi@chinet.UUCP (Irving Moy) writes:

>>	I tried 'gears' at a size factor of 4 and the resulting output is
>>quite dark.  The background is a nice UNC blue but the gear surfaces are
>>very dark and so is the reflecting polygon underneath the gears.
>>Has anyone else tried to raytrace 'gears' with Mark's program yet???
>>Enquiring minds want to know.....

	To be perfectly honest, I have never run gears at size factor 4.
	I will try to run one soon, but I am using a modified version of
	the ray tracer (which may be available soon) so I don't know
	what it will tell you.

>vixen% ray -i gears.nff -o gears.pic -t
>ray: (9345 prims, 5 lights)
>ray: inputfile = "gears.nff"
>ray: resolution 512 512
>ray: after adding bounding volumes, 10516 prims
>				    ^^^^^
	Oops.  I can see this coming.

>   From defs.h:
>#define MAXPRIMS        (10000)

	Guess I should bump up the MAXPRIMS, and insert some error
	checking code in the parser to figure out if I overrun this
	array.  Sorry guys.

>> (BTW, if you look closely at 'sphereflake',
>> you can see Elvis (recursively, of course)).
	
	Eeeeewww!  Look at the ugly face I drew!

>   To Mark VandeWettering: Hey, thanks for the ray tracer.  I don't suppose
>you could send me a disk drive to store all these picture files on could you?
	
	You are indeed welcome.  The responses that I have gotten have
	all been favorable, so I feel pretty good.  Stay tuned for
	revision 2, which will be better commented, faster, and include
	a bibliography of stuff to read to understand the guts of the
	tracer.

>Ron Hitchens		ronbo@vixen.uucp	hitchens@cs.utexas.edu

Mark VandeWettering