Robert Webb (webb++at++cgl.citri.edu.au)
Fri, 18 Feb 1994 18:48:21 +1100 (EDT)
- The Performer documentation we have describes a function pfGlobalGState(),
but this function does not seem to actually exist (and there is no prototype
for it in the header file). How do I set up global pfGeoState defaults
without it?
- 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.
- I've read the pfLight man page and I'm still not sure how to position lights
properly. It says that for lights like the sun, which have a fixed position
in the world, pfLightOn() should be called every frame with only the viewing
transformation on the matrix stack. I understand the concept, but how do I
actually do it? Performer does all the drawing and transformations for you
so do I need some sort of call-back to call pfLightOn() at the right moment?
If I set up lights in a pfGeoState with:
pfGStateAttr(gstate, PFSTATE_LIGHTS, lights);
and associate this with a pfGeoSet, then is that the same as using
pfLightOn() with the modelling transformations for that GeoSet on the stack?
That is, will the lights then move with the object like lights on a car? Or
does this simply use the lights but not affect their position? Do you still
need to call pfLightOn()?
Again I would like to use pfGlobalGState() to define global non-moving
lights, but this is unavailable.
- Ultimately it would be nice if pfGeoStates could be attached to any node,
and inherited by children. A pfGroup which holds all the various geometry
nodes for an object could then define materials etc. for all its children,
without each pfGeoSet having to do this itself to override the global state.
Does every little pfGeoSet really need its own pfGeoState? If so, is this
efficient provided consecutive children use the same pfGeoState?
Many thanks to anyone who answers any of these questions.
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