From: Yair Kurzion (yair++at++polygon.engr.sgi.com)
Date: 05/09/2001 14:40:05
Hello Henning !
The APP traversal runs during the call to pfSync. pfGetTravMat
reports the traverser matrix based on the DCS matrix contents before the
call to pfSync.
If this does not happen in your code, can you provide a short sample code
demonstrating the problem ?
Thanks,
-yair
>
> Hi pfUsers,
>
> I'm working fpr virtuel car driving simulator with Performer 2.4 and RedHat
> LINUX with a Pentium 533Mhz Prozessor and a NVIDIA TNT 2 graphicboard.
>
> I need to place the current Channelview into the coordinates of an object
> (for instance inside a Car), which is depending on various DCS,s in the
> scene path. So, I need the complete transformation of this object (root to
> object). Actually I use inside a viewing_update_callback(pftraverser * trav,
> void * data) of the Application Traversal the Performerfunction:
> pfGetTravMat() to get the apparently current transformation matrix of this
> node!
>
> But it doesent work so fine.
>
> I'm getting only the transformation matrix of a frame one step in the past.
> So if my parent DCS node is triggerd with a new postion the viewing position
> is staying on its old value, during the object changed its postion. Only in
> the next frame step the viewing position is triggered by the parent DCS's.
> But if the objekt is still moving with a velocity the viewing position will
> be shiftet during the time the DCS is triggerd with a volicity. I also tried
> out to place the callbackfunction as Pre or as Post Traversal function in of
> the PFTRAV_APP. But I only got the same problem.
>
> I solved this mismatch, that I take the transfromation matrix of the
> traversed node directly from the parrent DCS nodes instad from
> pfGetTravMat() with a own function. But due to that I found a missing of
> performance.
>
> My question is. Is there a bug in pfGetTravMat()? Or how can I get the
> current transformation matrix of an traversed node o a beter way?
>
> Thanks for help.
>
> Henning
>
>
> ----------------------------------------------------------------------------
> ---
> Dr. Henning Rose -Research Physicist-
> Competence Center Informatik GmbH
> Departmet of Simulation
> Lohberg 10
> 49716 Meppen
> -Germany-
>
> Tel.: (+49) 5931 / 805 361
> email: Henning.Rose++at++cci.de
> ----------------------------------------------------------------------------
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>
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