Re: Performer questions

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John Rohlf (jrohlf++at++tubes)
Tue, 8 Mar 94 10:05:14 PST

> >> - In one of our applications at least, the culling does not work properly.
> >> Objects suddenly vanish before they leave the viewing frustrum. Any ideas
> >> why this could be? We are not changing any of the GeoSets or other data in
> >> the hierarchy after it has been initially set up.
> >
> > Print out the scene with pfDebugPrint and make sure your bounding
> > boxes are reasonable.
>
> I found that for linestrips, anyway, Performer only checks if the first
> point or so of the lineseg is in the viewing frustum, regardless of
> the bounding box. Perhaps this little speed enhancing trick is at work
> in other types of GeoSets?
>
> I overcame it by installing a node pre-cull callback like this:
> node_cull_pre_cb() { pfCullResult(PFIS_ALL_IN); return PFTRAV_CONT; }
>
> It was most frustrating to watch my trajectory line segments disappear
> any time the origin wasn't in view.

        I'd like to get to the bottom of this. We don't do anything
special for linestrips or any other pfGeoSet type. If you are able,
send me an application and/or database which illustrates the
problem and I'll find out what's going on. Also, send me the
following information:

        1. Which Performer release are you running?

        2. What application: perfly or custom?

        3. What multiprocessing model?

        4. What culling mode (pfChanTravMode)?

N.B.: There is an easier way than using pfCullResult(PFIS_ALL_IN);
described above. Call pfNodeTravMask(node, PFTRAV_CULL, 0, PFTRAV_SELF, PF_SET);
With a cull mask of 0, the node will be not be cull-tested and
will be automatically accepted.

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