Re: Triangle Troubles
Angus Dorbie (dorbie++at++sgi.com)
Wed, 03 Jun 1998 11:30:56 -0700
Uwe Pachler wrote:
>
> hmmmm. This is my clipping plane setting:
>
> #define NEAR_DISTANCE 0.2 // distances for near/far object culling
> #define FAR_DISTANCE 20000.0 // see pfChanNearFar
>
> ...
>
> pfChanNearFar(chan, NEAR_DISTANCE, FAR_DISTANCE);
>
> Is that a problem?
>
> But it shouldn't, because everything else looks normal.
>
> Another point is that the effect occurs much more often
> when I start the application using a tracking system (the user's head
> will be tracked and the view will be adjusted - we use an HMD). If I start
> it with mouse control, the error occurs only sporadic. I assume that this
> is because the view coordintates change every frame when I use the
> tracker.
>
> Uwe Pachler
>
> > Hi Uwe,
> >
> > could it be something as simple as the setting of your near and far
> > clipping planes ??
> >
You should draw stuff like gas masks to the overlay planes and
then set your viewport to a region bounding the eye holes. You can
do this in a VR system because the mask is slaved to the head and
shouldn't move w.r.t. the eye.
Cheers,Angus.
--
"Only the mediocre are always at their best." -- Jean Giraudoux
For advanced 3D graphics Performer + OpenGL based examples and tutors:
http://www.dorbie.com/
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on Mon Aug 10 1998 - 17:57:30 PDT