[vtkusers] CrystalEyes stereo on an SGI Prism

[Michael Scarpa]

Jens,

On Wed, Jun 28, 2006 at 04:24:21PM +0100, Jens Thomas wrote:
> Hi Michael,
> 
> Michael Scarpa wrote:
> >Jens,
> >
> >On Wed, Jun 28, 2006 at 03:29:07PM +0100, Jens Thomas wrote:
> >  
> >>Currently, when I try it, I get the following message:
> >>
> >>Adjusting stereo mode on a window that does not support stereo type 
> >>CrystalEyes is not possible.
> >>    
> >Are you making sure that the render window you create is capable of
> >producing stereo images?  If I'm not mistaken, you have to call
> >vtkRenderWindow::StereoCapableWindowOn() (see VTK online documentation
> >for details) *before* any rendering is done.  Otherwise VTK complains if
> >you try to activate stereo rendering, because by default it does not
> >create a stereo-capable window.  I hope this helps!
> 
> I think I'm getting this bit right, because if I change the 
> SetStereoTypeToCrystalEyes call to SetStereoTypeToRedBlue, then I get 
> Red/Blue stereo rendering, so I think I've correctly enabled the stereo 
> capability for the vtkRenderWindow.

I've just tried it out.  As a matter of fact, I have found the following
behaviour on our test machine here:
If I call vtkRenderWindow::SetStereoOn() *without* a prior call to
neither vtkRenderWindow::StereoCapableWindowOn() nor
vtkRenderWindow::StereoRenderOn(), I do indeed get correct red/blue
stereo rendering.  But, if I add a call to
vtkRenderWindow::SetStereoTypeToCrystalEyes() *before* the call to
StereoRenderOn(), I do indeed get the error message you quote.  The
solution here was to put a call to StereoCapableWindowOn *before* the
first rendering (e.g. before starting the other calls).

Curiously enough, if instead I move the call to
SetStereoTypeToCrystalEyes() to *after* the call to StereoRenderOn(), I
do *not* get any error message, but I also don't get any stereo
rendering.

So the solution to your problem might still be a missing call to
StereoCapableWindowOn().  As far as I know, this will make sure that the
proper window is created with the proper OpenGL bits set to allocate a
left and a right eye buffer, etc.  In case of red/blue stereo, these
settings are not necessary, and so VTK does not complain.

Kind regards,

Michael