Steve Baker (steve++at++mred.bgm.link.com)
Thu, 14 Nov 96 10:32:03 -0500
1) He is using cyclebuffers to sync his vertex updates
(presumably in APP) with the DRAW process. This is good.
2) Since he is changing his vertex coords, he must also
recompute the bounding volume - since Performer doesn't
do that for you. This is good too.
I don't think that Performer knows how to take the bounding
box for a pfGeoSet from a cyclebuffer - so isn't there a
problem with the synchronization of the bounding volume change
with the vertex update?
Brian - you also need to be aware that if you change the bounding
volume of an object that is deep within the database tree, Performer
has to go and recompute all the bounding volumes of the nodes above
the one you are changing. This can be time-consuming.
Making the bounding volume big enough to contain all possible
positions of the GeoSet vertices is often the best solution -
it depends on the amount of geometry in that node which would be
passed on to GL unnecessarily when the overly-large bounding
volume is on-screen, but the geometry isn't.
Steve Baker 817-619-1361 (Vox-Lab)
Hughes Training Inc. 817-619-8776 (Vox-Office/Vox-Mail)
2200 Arlington Downs Road 817-619-4028 (Fax)
Arlington, Texas. TX 76005-6171 Steve++at++MrEd.bgm.link.com (eMail)
http://www.hti.com (external) http://MrEd.bgm.link.com/staff/steve (intranet)
http://web2.airmail.net/sjbaker1 (external)
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