[vtk-developers] Buggy non-stereo rendering on a stereo capable window

Francois Bertel francois.bertel at kitware.com
Wed Dec 19 12:34:18 EST 2007


Hi Thierry,

I have two questions:

1. Which StereoType do you use?
2. does it work correctly with VTK5.0?

On 12/13/07, Thierry.CARRARD at cea.fr <Thierry.CARRARD at cea.fr> wrote:
> Hi all,
>
> The following test case produces flickering image on stereo capable
> machines (i.e. with a Quadro board) :
>
> renwin->StereoCapableWindowOn()
> renwin->StereoRenderOff()
> assuming that renwin is an OpenGL render window
>
> This is due to drawing to GL_BACK_LEFT buffer only instead of GL_BACK
> (which in stereo mode duplicates written pixels to GL_BACK_LEFT *AND*
> GL_BACK_RIGHT buffers).
>
> This is due to the initialisation of the BackBuffer member of
> vtkOpenGLRenderWindow to GL_BACK_LEFT.
>
> Moreover, this is incoherent with the rest of vtkOpenGLRenderWindow.cxx
> in which, in the SetPixels method, we explicitly call
> glDrawBuffer(GL_BACK).
>
>
> My guess for a solution is the following:
>
> 1. ensure that every call to glDrawBuffer in all VTK sources uses
> renwin->GetBackBuffer() (or GetFrontBuffer) as its argument.
>
> 2. ensure that the BackBuffer (resp. FrontBuffer) member of
> vtkOpenGLRenderWindow is always equal to GL_BACK (resp. GL_FRONT)
> whenever renwin->GetStereoRender() is false. Otherwise (when stereo
> render is on), ensure that BackBuffer (resp. FrontBuffer) is always
> equal to either GL_BACK_LEFT or GL_BACK_RIGHT (resp. GL_FRONT_LEFT or
> GL_FRONT_RIGHT).
>
>
> PS: check
> http://www.opengl.org/documentation/specs/man_pages/hardcopy/GL/html/gl/
> drawbuffer.html for details.
>
>
> Best regards,
> Thierry.
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>


-- 
François Bertel, PhD  | Kitware Inc. Suite 204
1 (518) 371 3971 x113 | 28 Corporate Drive
                      | Clifton Park NY 12065, USA



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