Re: Picking with asymmetric Viewing Frustum
Marc Erich Latoschik (marcl++at++TechFak.Uni-Bielefeld.DE)
Tue, 03 Nov 1998 12:39:17 +0100
Wolfgang Trog wrote:
>
> Hi Performers,
>
> sorry, I hit the wrong button. Next try !
>
> I try to do picking in a channel with an asymmetric viewing frustum. The
> viewing frustum is set by pfMakePerspChan. E.g. to values 30 deg to
> left, 32 deg to right and 22.5 top and bottom. Then, I do picking with
>
> NrHits = pfChanPick( Channel,
> PFPK_M_NEAREST |
> PFTRAV_IS_PRIM |
> PFTRAV_IS_PATH |
> PFTRAV_LOD_CUR,
> ChannelX, ChannelY, 0.0f, PickList );
>
> The picking calculation seems to use only the smallest value of
> right/left and top/bottom. So the picking results are shifted to the
> left/right and top/bottom. In case of my example, the picking results
> are shifted to the right (looks like a 2 deg shift).
> When I supply symmetric values to pfMakePerspChan, this works fine.
>
> Can anybodye help me ?
>
Yes and no Wolfgang ;),
sorry the answer comes late, but im currently running into the same
problem.
To disaapoint you, read the relnotes of Performer 2.2
under the section Bugs and Workarounds it is said that picking
in an asymetric frustum is not currently supported.
Sorry for that.
I still try to figure out how to do it. Right now it seems that the only
possibility is to hold all scene geometrie in a seperate process and to
apply object and viewpoint transformation on my own. :( That is of
course
the worst thing but i have no other ideas...
Does anyone have a good one for that problem?
bye
Marc
********************************************************************************
Marc Erich Latoschik, AG-WBS, Technische Fakultaet der Universitaet
Bielefeld
Universitaetsstrasse 25
Postfach 100 131
33501 Bielefeld
Raum M4-122
Fon: (0521) 106 2919
Fax: (0521) 106 2962
marcl++at++techfak.uni-bielefeld.de
http://www.TechFak.Uni-Bielefeld.DE/techfak/persons/marcl/
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