Re: Viewing Frustrum in Stereo

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Torsten Moeller (tmoeller++at++cgrg.ohio-state.edu)
Sat, 16 Dec 1995 18:28:34 -0500

On Dec 13, 22:13, Nathaniel Bletter wrote:
> Subject: Re: Viewing Frustrum in Stereo
> I found this same problem, that the FOV wasn't changed with a
pfMakePerspFrust,
> unless you also did a pfChanFOV to sort of wake it up. This doesn't make a
> whole lot of sense since there isn't really a FOV in off-axis projections.
> Maybe it's been fixed in 2.0.

I included a

            pfChanFOV(Chan, x, y);
            pfChanFOV(StereoChan, x, y);

in my code and it works! x and y could be almost any value. That seems
very strange. The only thing, which still bothers me is that, when I
switch the gui on/off, it doesn't keep the aspect ratio constant, as achieved
with

            pfChanAutoAspect(ViewState->masterChan, PFFRUST_CALC_VERT);

Is there a solution to that?

Thanks to everybody who helped me so far,

                                                Torsten.
>
> On Dec 12, 6:00pm, Torsten Moeller wrote:
> > Subject: Viewing Frustrum in Stereo
> > I do full screen stereo on a Crimson and have a problem to adjust the
> > aspect ratio properly. In mono, it is easy:
> >
> > pfMakeSimpleFrust(ViewState->masterChan, fov);
> > pfChanAutoAspect(ViewState->masterChan, PFFRUST_CALC_VERT);
> >
> > Whenever I change the display (including/excluding the gui) it adapts
> > the view in x and y direction.
> >
> > In stereo however, I use:
> >
> > pfChanViewport(StereoChan, 0.0f, 1.0f, 532.0f/YMAXSCREEN, 1.0f);
> > pfChanViewport(Chan, 0.0f, 1.0f, 0.0f, 491.0f/YMAXSCREEN);
> > pfChanViewOffsets(..)
> > pfMakePerspFrust(StereoChan, -x +ioc, x +ioc, -x, x);
> > pfMakePerspFrust(Chan, -x -ioc, x -ioc, -x, x);
> >
> > Here the view gets distorted in the y (vertical) direction, because the
> > aspect Ratio is roughly twice as big. If I try to take care of this
> > problem using:
> >
> > pfFrustAspect(StereoChan, PFFRUST_CALC_VERT, 0.975);
> >
> > it is ignored.
> >
> > Does anybody know what I am doing wrong here?
> >
> >
> > Torsten.
> >
> > --
> > Research Assistant ACCAD
> > tmoeller++at++cgrg.ohio-state.edu Ohio State University
> >
> >
> >-- End of excerpt from Torsten Moeller
>
>
>
> --
>
> Nat Bletter
> SRI International
> nat++at++od.sri.com
> http://os.sri.com/people/nat/
> (415) 859-4358
>-- End of excerpt from Nathaniel Bletter

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