[Paraview] Running paraview with MPI

[Berk Geveci]

> > This is expected. Unless off-screen rendering is enabled, ParaView will
> > create a new render window on each process. These windows should not be
> > covered by other windows in any way, otherwise, the parallel image 
> > compositing will not work. This is because the image buffer is
> > grabbed during compositing. There are a few ways of avoiding this:
> > 
> > 1. send each window to a different display; this is the common way
> > of running paraview on a cluster
> 
> I just tried to do it this way (started two X servers and arranged for 
> each window to have its own), but (still using the mandelbrot source) I 
> just got black renderer windows. When I interact with the scene, it 
> appears, but as soon as I release it an it gets fully rendered the 
> display area goes black...

Hmmm. Something must be going wrong in the compositing. Does changing
any of the "Parallel rendering parameters" in Genera Setting make
any difference ?

> > 2a. On Unix/Linux, compile paraview with mesa or a combination of 
> > another GL and mangled Mesa and use off-screen rendering
> > 2b. On Windows, use off-screen rendering 
> > To enable off-screen rendering, you have to define the PV_OFFSCREEN
> > env. variable. Note that this will only work with the Windows binaries,
> > on Unix/Linux, you have to recompile VTK and ParaView. I can point
> > you to some documentation if this is what you want.
> 
> This would be very helpful. Thanks.

I recently posted the following messages to the VTK mailing list:

About GL and mangled Mesa:

You can not. You have to use mangled mesa which allows you to
link against both nvidia's GL and mesa. You then create
different rendering objects when you want to use the mesa
off-screen. Look at
VTK/Examples/MangledMesa/README.txt
and the examples
in VTK/Examples/MangledMesa/Tcl

About compiling Mesa mangled:

Here is how I do it:

1. use  Makefile.X11 to build Mesa (not configure)
2. edit Make-config, add -DUSE_MGL_NAMESPACE to CFLAGS of the target
linux-static 
3. compile the target linux-static
4. rename libGL.a to something like libMGL.a
5. follow the instruction in VTK/Examples/MangledMesa/README.txt

Some of the later versions of Mesa might not compile since the mangled
stuff was broken for a while. I usually use Mesa 4 (cvs should also
work).