Manta Interactive Ray Tracer Development Mailing List

Text archives Help


Re: [Manta] Image degrades as more processors get involved!


Chronological Thread 
  • From: James Bigler <bigler@cs.utah.edu>
  • To: Christian Odom <cnsodom@gmail.com>
  • Cc: "Solomon Boulos" <boulos@cs.utah.edu>, "Dirk Reiners" <dirk@infiscape.com>, manta@sci.utah.edu
  • Subject: Re: [Manta] Image degrades as more processors get involved!
  • Date: Wed, 5 Sep 2007 22:08:31 -0600
On 9/5/07, Solomon Boulos <boulos@cs.utah.edu> wrote:

Hi Dirk and Christian,

The change camera stuff looks good.  As you mentioned (Dirk), using
Manta's transaction interface does correctly handle the thread-safety
for the Camera (the transactions are only called after rendering has
completed for that frame).

Try running Manta with SSE disabled on your amd64 box by turning SSE
off in the cmake settings (I believe you did this for the ia64 run as
well).


Do I need to remove the flags:   -msse -msse2 -msse3 as well?

You could, but the manta code won't generate the SSE code paths if you disable MANTA_SSE via ccmake.

Does the same problem occur for bin/manta with your camera?

I'll check this out tomorrow.

Another thing to check is to change the depth of the ray tree. You can change it from the command line with --madepth 0 or by pressing 'd' and 'D' in the XWindow.


That is the last picture I posted.  So yes the problem is there.
Im not sure if the noise on the sphere and in the bottom of the left
frame is the same type of noise.
It doesnt move like when I use multiple processors. If I just run bin/manta
with the default camera everything looks fine.

I've seen this behavior and it is almost always due to an uninitialized variable. The other possibility is that somehow NaNs are being introduced. My money is on an uninitialized variable.

James





Archive powered by MHonArc 2.6.16.

Top of page