[vtk-developers] VTKEdge on OS X 10.6

Fauze Polpeta fauze.polpeta at gmail.com
Fri Feb 19 20:21:17 EST 2010


Dear David;

Last 2 weeks I'm pursuing to get vtkOpenGLGPUVolumeRayCastMapper properly
working on Mac OS X. In respect to that consider the following:

1) vtkOpenGLGPUVolumeRayCastMapper has been moved to VTK repository, but it
still can be found at

"https://www.kitware.com/svn/KWPublic/trunk/VTKEdge-5-4-0/" instead of
https://www.kitware.com/svn/KWPublic/trunk/VTKEdge/

2) The error you are facing is probably a consequence of the following
statements in vtkKWEOpenGLGPUVolumeRayCastMapper.cxx

#ifdef __APPLE__
this->LoadExtensionsSucceeded = 0;
return;
#endif

3) This was placed to avoid a bug in NVidia driver for Snow Leopard (a
infinite loop) but such statements were also affecting Leopard.

4) Today, I saw that these statements were removed from
vtkKWEOpenGLGPUVolumeRayCastMapper.cxx. So after updating your source code,
you will probably be able to get GPU-based Ray Cast working in Leopard but
not yet in Snow Leopard.

5) However, I'm facing two problems that I'm not able to set them as VTKEdge
issues or new NVidia bugs in Mac OS X.

a) GPU-based Ray Cast is not working for DICOM CT datasets that have more
than 170 images (aprox.) and are 512x512 in size. Resultant volume is very
"scratched".

b) Shading (3D Textures, etc) doesn't work as well. Interacting with the
volume is very compromised, I can say impossible.

6) I run the same tests on Linux and everything went fine.

7) I tried VolView 3.2, which, in principle, relies on the same approach
(perhaps, the same library) for performing GPU-based Ray Cast, but it
crashes when GPU support is active. My guess this is caused by the
statements mentioned in 2).

8) More on this you will find on my submissions to the VTKEdge mailing list:


http://public.kitware.com/pipermail/vtkedge/2010-February/000295.html
http://public.kitware.com/pipermail/vtkedge/2010-February/000296.html

Hope it helps you.

Best Regards

Fauze


On Fri, Feb 19, 2010 at 3:04 PM, David Gobbi <david.gobbi at gmail.com> wrote:

> I'm seeing the following error when I try to use the new GPU ray cast
> mapper on my Mac.  The last time that I tried VTKEdge on this machine
> (a few weeks ago) there were no problems.
>
>
> ERROR: In
> /Volumes/Work/Kitware/vtk-cvs/VolumeRendering/vtkOpenGLGPUVolumeRayCastMapper.cxx,
> line 4128
> vtkOpenGLGPUVolumeRayCastMapper (0x10081a000): Rendering failed
> because the following OpenGL extensions are required but not
> supported:
>
> Segmentation fault
>
>
> There are also some rendering errors related to combined clipping and
> cropping that I see under Linux.  Cropping blocks being displayed when
> they are not flagged, or blocks displayed on the wrong side of the
> clipping plane.  I'm not sure if these were present with VTKEdge.  I
> can provide screenshots when I get back to my Linux PC this evening.
>
>  - David
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