[Paraview] Segfault with OpenGL2

[Harald Klimach]

If I use this option via the X-server on the remote machine:

> I don't have an answer to your VGL problem yet, but in the mean time, are you tied to having to use it that way?  If not, you also have the option of running ParaView in client / server mode which may actually be more ideal for your situation: i.e. with pvserver running on the headless server and the ParaView GUI client on your local machine (workstation / desktop / laptop, etc.) and connecting to the remote server.  Doing so, you can actually bypass vgl and likely get much better performance.  If you're running an X server on the remote machine, you can do this by setting your DISPLAY variable to the local x server:
> 
> ssh foo at bigserver
> [foo at bigserver ~]$ DISPLAY=:0.0 pvserver
> Waiting for client...
> Connection URL: cs://bigserver.supercooldomain.com:11111
> Accepting connection(s): bigserver.supercooldomain.com:11111

I don’t get the error message box.
But, one thing I noticed now, is that in this case the Connection information in About Paraview shows me
a different OpenGL version string in the OpenGL2 compiled pvserver than in the one without OpenGL2
support.

with OpenGL2 the OpenGL-Version is: 3.2.0 NVIDIA 361.28
without, the OpenGL-Version is: 4.5.0 NVIDIA 361.28

Now I am somewhat confused, as the EGL built pvserver with OpenGL2 backend also complained about
OpenGL-Version 4.5.0 NVIDIA 361.28.

So, with legacy OpenGL rendering backend I have 4.5.0.
With OpenGL2, but no EGL I have 3.2.0.
With OpenGL2 and EGL I again have 4.5.0.

legacy OpenGL works via VirtualGL,
OpenGL2 works as a pvserver using the X display on the remote machine without any error message boxes
(I guess this is the option I’ll deploy now),
OpenGL2 and EGL works as pvserver, but somehow still requires me to set the DISPLAY=:0.0, if I am not mistaken,
and it has the reported error message pop-up, saying that remote rendering is disabled.