From: Angus Dorbie (dorbie++at++sgi.com)
Date: 04/11/2000 08:00:11
Is it culled for a frame or two or is it the error permanent? I'm
guessing there may be a transport delay for one set of data and not the
other when the new info gets propagated to the cull process. A bit
speculative at this stage.
Cheers,ANgus.
Bram Stolk wrote:
>
> Hello performers,
>
> I use a pfGeoSet for which I change the contents of the vertex array
> each frame.
>
> This means, that each frame, the bounding volume changes, and should
> be updated to ensure proper culling/isecting.
>
> In the manual page for pfGeoSet, I read:
>
> ... If the mode is
> PFBOUND_DYNAMIC, IRIS Performer will recompute the bound if the number of
> primitives, the primitive lengths array or the vertex coordinate arrays
> are changed. Note that IRIS Performer does not know if the contents of
> these arrays changes, only when the pointer itself is set. Recomputation
> of the bounding box can be forced by calling pfGeoSet::setBound with a
> bbox that is NULL.
>
> So each time I change the vertex array contents, I do:
> set->setBound(0,PFBOUND_DYNAMIC);
>
> Nevertheless, the geoset is occasionally culled when it should not
> have been. I use a CAVE setup, so I see some cave walls do culling,
> and others do no culling.
>
> Being quite puzzled about this, I decided to take more drastic
> measures, and to disable culling for the geode alltogether,
> using this func call:
> geode->setTravMask(PFTRAV_CULL, 0, PFTRAV_SELF | PFTRAV_DESCEND, PF_SET);
>
> Even this does not prevent the erroneous culling of my dynamically
> adjusted object!
>
> Can someone please enlighten me in the noble art of culling dynamic geometry?
> Many thanks,
>
> Bram Stolk
>
> --
> ------------------------------------------------------------------------------
> Bram Stolk, VR Specialist.
> SARA Academic Computing Services Amsterdam, PO Box 94613, 1090 GP AMSTERDAM
> email: bram++at++sara.nl Phone +31-20-5923059 Fax +31-20-6683167
>
> "I heard if you play the NT-4.0-CD backwards, you get a satanic message."
> "Thats nothing, if you play it forward, it installs NT-4.0"
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