MuJoCo on Windows 11 WSL 2 Black Screen

[HaomiaoZ]

Intro

Hi!

I am a graduate student, and I plan to use MuJoCo for my research project on robot learning.

My setup

MuJoCo Version: 3.3.3
Python Version: 3.12 in miniconda3 venv
OS Version: Ubuntu 22.04 in WSL 2 on Windows 11

My question

Initially just after setting up the conda env and install mujoco through pip install mujoco, I tried to run python -m mujoco.viewer, and no window will be opened. The error code is shown below:

libGL error: MESA-LOADER: failed to open swrast: /home/haomiaoz/miniconda3/envs/mujoco_test/bin/../lib/libstdc++.so.6: version `GLIBCXX_3.4.30' not found (required by /lib/x86_64-linux-gnu/libLLVM-15.so.1) (search paths /usr/lib/x86_64-linux-gnu/dri:\$${ORIGIN}/dri:/usr/lib/dri, suffix _dri)
libGL error: failed to load driver: swrast
/home/haomiaoz/miniconda3/envs/mujoco_test/lib/python3.12/site-packages/glfw/__init__.py:917: GLFWError: (65543) b'GLX: Failed to create context: BadValue (integer parameter out of range for operation)'
  warnings.warn(message, GLFWError)
ERROR: could not create window

After some search online, I found some people can resolve the error by adding the following line to the .bashrc file

export LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libstdc++.so.6

After adding this line, then rerun the terminal and run python -m mujoco.viewer, now a window would appear but it is all black.

I was wondering what package might be missing or misconfigured to cause this. Thanks in advance.

Minimal model and/or code that explain my question

No response

Confirmations

• I searched the latest documentation thoroughly before posting.
• I searched previous Issues and Discussions, I am certain this has not been raised before.

[traversaro]

For what regard the first problem it seems you have a really old libstdc++.so.6 in your conda environment, that is so old that it is not recent enough for your system GPU driver. While LD_PRELOAD is a workaround, perhaps you could simply try to update the libstdc++.so.6 installed by conda?

On the black screen, d3d12 is quite sensitive on the underlying driver. What happens if you pass LIBGL_ALWAYS_SOFTWARE=1 ? Which GPU do you have on your system?

[HaomiaoZ]

Hello @traversaro, thanks for the help!

I tried to update the libstdc++.so.6 using the command conda install -c conda-forge libstdcxx-ng. After that I tried to run python -m mujoco.viewer, the errors are gone, and now I can successfully get a window with black screen.

After that I tried export LIBGL_ALWAYS_SOFTWARE=1 then rerun the viewer, now it is showing the world and GUI correctly. One small problem is that I actually cannot drag and drop xml file to load the model.

I am able to load model through code, and rendering seems fine except the speed is a bit slow.

In terms of GPU, my laptop has two GPUs: Intel Arc Graphics (no specific series number) and Nvidia RTX 4050 Laptop GPU. Below is a snippet from task manager:

I guess I have three questions now:

1. what does the LIBGL_ALWAYS_SOFTWARE=1 do? I guess it forces to skip GPU, but just want to double check
2. Why I cannot drag and drop model files? I think it is a bit off the topic since it is more about rendering problem in this discussion, but just out of curiosity.
3. what are some steps I might able to try to use GPU to render?

Let me know what other info might be helpful and I can provide it. Glad the window is not all black at least. Thanks again!

[traversaro]

what does the LIBGL_ALWAYS_SOFTWARE=1 do? I guess it forces to skip GPU, but just want to double check

It indeed forces CPU-based rendering of OpenGL calls.

Why I cannot drag and drop model files? I think it is a bit off the topic since it is more about rendering problem in this discussion, but just out of curiosity.

I have no idea, but it could be related to some Wayland/X/WSLg incompat.

what are some steps I might able to try to use GPU to render?

Probably you can force d3d12 by removing the LIBGL_ALWAYS_SOFTWARE=1 env variables and forcing the use of d3d12 and the NVIDIA GPU instead of the Intel one by setting GALLIUM_DRIVER=d3d12 MESA_D3D12_DEFAULT_ADAPTER_NAME=NVIDIA . See gazebosim/gz-sim#2670 (comment) for a similar issue on the gz-sim side.

[HaomiaoZ]

Thanks for answering those questions!

I tried to remove LIBGL_ALWAYS_SOFTWARE=1 and set those two variables, and I can successfully use GPU for rendering. Nvidia GPU is occupied while I run mujoco after setting those two variables.

I don't have any other question for now. Thanks again for all the help @traversaro!