Incorrect image out (purple squares) with parallel GPU-based volume rendering
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
I originally reported this problem for 3.14.1 on the mailing list, see thread "Errors with GPU-based volume rendering" in November 2011. Just found that with 3.98.0 this problem still exists.
I tested with running 2 pvserver processes (on 2 nodes, one per node). The problem can be demonstrated by creating the default wavelet source and switching to GPU-based volume rendering. The output shows a few purple squares (see screenshot), presumably the image-space bounding boxes of the per-node rendered views.
On the console there's also some errors:
paulm@v41-6:~$ DISPLAY=:0.0 mpirun -x DISPLAY pvserver --use-offscreen-rendering Waiting for client... Connection URL: cs://v41-6:11111 Accepting connection(s): v41-6:11111 Client connected. after uniforms for textures ERROR (x501) Invalid value framebuffer has an attachment error framebuffer has an attachment error SetupRender ERROR (x506) invalid framebuffer operation ext framebuffer has an attachment error framebuffer has an attachment error after uniforms for textures ERROR (x501) Invalid value framebuffer has an attachment error framebuffer has an attachment error SetupRender ERROR (x506) invalid framebuffer operation ext framebuffer has an attachment error framebuffer has an attachment error render clipped 1 ERROR (x506) invalid framebuffer operation ext render clipped 1 ERROR (x506) invalid framebuffer operation ext after uniforms for textures ERROR (x501) Invalid value [...]
The render nodes have NVidia GTX460's and driver 295.40. I can't easily test a newer driver version, but we'll be doing a cluster upgrade soon anyway, so I'll retest then.
There's workaround mentioned in the mailing list thread that still works: save to a state file and reload the state (this even works without restarting paraview).