Re: preCull Callback

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From: Brad Colbert (bcolbert++at++acm.org)
Date: 01/26/2001 09:59:07


You may want to take a look at the man pages for pfTraverser.

The part of interest to you is pasted below:

       pfCullResult, pfGetCullResult, and pfGetParentCullResult
       can all be called in the pre-cull callback and all but
       pfCullResult may be called in the post-cull callback.
       pfGetCullResult returns the result of the cull for the
       node that the cull callback is associated with.
       pfGetParentCullResult returns the cull result for the par-
       ent of the node that the cull callback is associated with.
       When called within the pre-cull callback, pfCullResult
       specifies the result of cull for the node that the pre-
       cull callback is associated with. This essentially
       replaces default IRIS Performer cull processing with user-
       defined culling. result is a token which specifies the
       result of the cull test and should be one of:

              PFIS_FALSE
                   Node is entirely outside the viewing frustum
                   and should be pruned.

              PFIS_MAYBE | PFIS_TRUE
                   Node is partially inside the viewing frustum
                   and the children of the node should be cull-
                   tested.

              PFIS_MAYBE | PFIS_TRUE | PFIS_ALL_IN
                   Node is totally inside the viewing frustum so
                   all the children of the node should be triv-
                   ially accepted without further cull testing.

       If pfCullResult is not called within the pre-cull call-
       back, IRIS Performer will use its default geometric
       culling mechanism that compares node bounding volumes to
       the current culling frustum to determine if the node may
       be within view.

-B

Sakns wrote:

> Hi there,
> When I attach a precull callback to a pfNode it does not get
> called when the pfNode is outside the channel view frustum. Is
> this the correct behavior?
> I am using Performer 2.4 on an Octane.
>
> Thank you.
>
> =====
> Athanasios Gaitatzes (Saki)
> e-mail: gaitat++at++yahoo.com
> url: http://www.i.am/gaitatzes
>
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--
Brad Colbert
GreyStone Technology, Inc.
bcolbert++at++acm.org
(858) 874-7000


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