[vtkusers] building without libGL

[Kyle Cronan]

I was able to do this build, and off-screen rendering of charts is
working fine.  I had to change the KIT_LIBS for Widgets to
OSMESA_LIBRARY instead of OPENGL_gl_LIBRARY.  As for volume rendering,
I just removed it from being activated by VTK_USE_RENDERING, but
perhaps the same change would also work.

If there is interest in putting together a patch that sets the correct
libraries automatically, contact me and I will assist with that.

Best,
Kyle

On Sun, Feb 6, 2011 at 1:56 AM, Kyle Cronan <kyle at cronangraf.com> wrote:
> Hi,
>
> I'm currently using VTK 5.4 on a web server with OSMesa.  I was able
> to build 5.4 without any libGL installed on the system at all, and in
> fact, if I recall correctly, I had to make sure it was removed and
> reconfigure with CMake before I was able to get OSMesa working
> properly (OSMesa didn't like being linked in when regular GL was also
> present).
>
> Now I would like to upgrade to the 5.6 series to take advantage of the
> new charts.  But when I try to configure VTK 5.6.1 I get this error:
>
>  CMake Error: The following variables are used in this project, but
> they are set to NOTFOUND.
>  Please set them or make sure they are set and tested correctly in the
> CMake files:
>  OPENGL_gl_LIBRARY (ADVANCED)
>     linked by target "vtkVolumeRendering" in directory
> /home/kyle/VTK/VolumeRendering
>     linked by target "vtkWidgets" in directory /home/kyle/VTK/Widgets
>
> The only way to get a build going seems to be to turn off rendering
> entirely.  Recommendations?  Is this a known regression?
>
> Note that as far as I know I don't actually use either of those kits.
>
> Thanks,
> Kyle Cronan
>