Re: [info-performer] pfChannel and pfMultiprocess

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From: Allan Schaffer (allan++at++sgi.com)
Date: 05/31/2003 15:18:05

Hi Brad,

Brad Schwagler wrote:
> I have a rear view mirror set up on the stereo driving
> simulation as a separate pfChannel. The rear view
> mirror does work when using:
>
> pfMultiprocess(PFMP_APPCULLDRAW);
>
> We managed to speed up the simulation by changing the
> above option to:
>
> pfMultiprocess(PFMP_APPCULL_DRAW);
>
> The problem with this is the second pfChannel is not
> displayed at all.
>
> Why does it affect the pfChannel when using the
> different options? Is there a better way to display
> the pfChannel without slowing down the speed?

Using an MP mode is definitely the best direction to improve throughput;
you might even try APP_CULL_DRAW.

This disappearing channel must be the result of some other problem; the
APPCULL_DRAW mode works with other multichannel apps. In particular,
look through your code for any data allocated in the APP process but
used in the DRAW process, that wasn't allocated in shared memory.

Another approach: have a look into the "multichan.c" sample in
/usr/share/Performer/src/pguide/libpf/C .. there may be something in
there which differs from your code, that could give a clue. And
finally, try modifying multichan.c to reproduce the problem. If you can
make a test case from that, send it our way and we'll check it out.

Allan 

-- 
Allan Schaffer                                            allan++at++sgi.com
Engr. Manager, Core Rendering                            1-650-933-2160
Silicon Graphics                                     http://www.sgi.com

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