[Paraview] Dual-headed output from a single GPU?

[Paul Melis]

Hello,

Paul Melis wrote:
> Berk Geveci wrote:
>   
>> > Yeah, unfortunately it is hard for us to provide binaries with MPI
>> > support because MPI is implemented with different (internal) APIs by
>> > different vendors. We would have to create a different binary for each
>> > MPI distribution.
>> >
>>     
> No problem, building paraview isn't really difficult and so I now have
> an mpi-enabled version that seems to do the trick.
Or so I thought...

Just to summarize my configuration:
* I'm using (for now) a single render node with a single GPU, but
dual-headed output
* X is configured to run one server, with two screens (:0.0 en :0.1)
* I'm running pvserver with
mpirun -bynode -np 1 ./pvserver -tdx=2 -tdy=1 -display :0.0 : -np 1
./pvserver -tdx=2 -tdy=1 -display :0.1
* I'm running the GUI from a different system through an SSH tunnel to
port 11111 on the render node
* I'm using paraview 3.6.1 on 32-bit Ubuntu Linux boxes

The first thing that's off is that although I get undecorated Paraview
render areas on each panel display they don't fill the whole screen
(only roughly 75% in both width and height).

Secondly, when loading a dataset and e.g. extracting an isosurface the
rendering seems to work fine (minus the not completely full-screen
render area). I can also see the two display match up nicely (I haven't
specified any mullion setting so I'm assuming they get set to zero
pixels). So far so good. But when I switch to volume rendering I get the
strange artifact that each display renders only half of the total volume
set; the left display only does the upper half, the right only the lower
half. Even when the complete volume is moved so it is fully shown on
only one display only half of the set is rendered.  This seems to
suggest that there is some kind of sort-last rendering going on, instead
of sort-first.

Any clues?
Paul