I am the principal developer and sole maintainer of VirtualGL, a Linux OpenGL remote display framework. Without going into too much gory detail about how VirtualGL works, suffice it to say that one particular VirtualGL mode emulates the GLX API using EGL/DRI commands, and that mode and only that mo…

I believe that EGLBE: Test/Fix issues with draw buffer state · VirtualGL/virtualgl@adabbd9 · GitHub accidentally fixed this. I can no longer reproduce the issue after that commit.

It may be tricky, but folks on the VTK forum would I’m sure be very interested to see a pure-VTK example of this issue to help debugging (that is, to remove Slicer-related complexities). E.g. maybe one could start with an example like this one and add some depth peeling and transparent objects.

If I could bring up a VTK-only example, it would greatly facilitate me debugging the issue myself. Alas, I have tried to bring up a few of them without success. The main issue is that all of the examples I have found require newer versions of VTK, but the only machine I have that supports EGL/DRI …

If you can diagnose from the source code that’s great. But just FYI if you are able to run Slicer on the machine you can run vtk examples too. If you download the example linked above to /tmp/SampleRayCast.py, and then give it a .vtk volume file as an argument it should work for you like this exam…

Thanks for the tip about running VTK examples. I guess I would just need an example that demonstrates the same type of rendering that Slicer performs when depth peeling and Display ROI are both enabled. Unfortunately, such an example is beyond my ability to produce. After examining the code and t…

GitHub issue filed against VirtualGL: EGL back end: incorrect rendering with 3D Slicer when depth peeling and "Display ROI" are both enabled · Issue #168 · VirtualGL/virtualgl · GitHub

stripped-down program without a more stripped-down program Could you try this implementation of the example (see CorrectlyRenderTranslucentGeometry ) which is the up-to-date and maintained one. (Thanks @Sankhesh_Jhaveri for pointing this out :pray:) Note that I didn’t have a chance to check if i…

Thanks @jcfr :pray: @DRC will you be able to build and test the example? If not @muratmaga and I have been discussing the option of creating a python test script to see if we can replicate the issue in pure VTK without Slicer.

@pieper I was finally able to get that exact version of VTK to build on my machine, but unfortunately, the issue does not reproduce with the CorrectlyRenderTranslucentGeometry example.

@pieper I have no experience whatsoever with that and would not even know how to begin.

Trying to diagnose an issue with VirtualGL and Slicer

Development

pieper (Steve Pieper (Isomics, Inc.)) May 28, 2021, 8:11pm 20

You could try adding depth peeling to the example code @alireza added here: Incorrect volume rendering bounds - first and last slice - #5 by alireza

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Trying to diagnose an issue with VirtualGL and Slicer

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