Xlib: extension "GLX" missing on display ":20" when using x11vnc and fluxbox

[BoyiZhao]

System:

• OS version: Ubuntu 22.04
• Python version: Python 3.10
• SAPIEN version: sapien==3.0.0b1
• Environment: Server with xvfb

Describe the bug
When running a Python program that invokes GUI using x11vnc + fluxbox, the following error occurs:

Xlib: extension "GLX" missing on display ":20".

This issue is specific to the virtual desktop setup and does not occur when running the program directly on the default GNOME desktop environment.

To Reproduce
Steps to reproduce the behavior:

1. Follow the instructions from the SAPIEN project to set up the virtual desktop. Run the following command to start x11vnc:

   x11vnc -create -env FD_PROG=/usr/bin/fluxbox -env X11VNC_FINDDISPLAY_ALWAYS_FAILS=1 -env X11VNC_CREATE_GEOM=${99:-1920x1080x16} -gone 'pkill Xvfb' -nopw

2. Connect to the virtual desktop using VNC Viewer.
3. Export the display in the terminal: export DISPLAY=:20.
4. Run a Python program with GUI, such as the SAPIEN examples.

Expected behavior
The GUI program should render correctly without any errors related to GLX.

Screenshots
lanuch the virtual desktop

connect using vnc viewer

run my program

Additional context

• The hardware configuration is the same as another machine (Ubuntu 22.04 + RTX 3090) where this error does not occur.
• Installing libgl1-mesa-dev did not resolve the issue.
• The error only occurs in the x11vnc environment; running the program on the GNOME desktop works as expected.

[fbxiang]

Thanks for the report. Unfortunately, I have also met this problem before but did not find a solution. The problem simply disappeared after several months with several system updates.
My suggestion would be to keep your system up-to-date and see if the problem is resolved.
Another thing to try is that you may try to run Vulkan's official test program vkcube and see whether it works and uses the correct GPU. If vkcube also does not work, you can probably seek help in the Vulkan community, and they probably know a lot more about debugging your rendering setup.
If you figure out the reason yourself, it would be great that you let us know the solution so we can improve the documentation.

[BoyiZhao]

Thanks for the report. Unfortunately, I have also met this problem before but did not find a solution. The problem simply disappeared after several months with several system updates. My suggestion would be to keep your system up-to-date and see if the problem is resolved. Another thing to try is that you may try to run Vulkan's official test program vkcube and see whether it works and uses the correct GPU. If vkcube also does not work, you can probably seek help in the Vulkan community, and they probably know a lot more about debugging your rendering setup. If you figure out the reason yourself, it would be great that you let us know the solution so we can improve the documentation.

Thanks, I have tried vkcube. It runs successfully in the GNOME desktop. I will try to use SAPIEN in the desktop environment now, but I will still try to figure out the reason. I will make some update if I find the solution.