EGL initialization error

Hi,

I’ve recently come across the following error, on a machine with Nvidia driver version: 440.33.01 CUDA version: 10.2, when trying to use EGL for headless rendering. The same exact code was running properly on a machine with CUDA Version 10.1 and driver version 390.

Any idea how to fix the issue? I’ve tried reinstalling dm_control with pip.

  File "/home/aj/miniconda3/envs/rlpyt/lib/python3.7/site-packages/dm_control/suite/__init__.py", line 28, in <module>
    from dm_control.suite import acrobot
  File "/home/aj/miniconda3/envs/rlpyt/lib/python3.7/site-packages/dm_control/suite/acrobot.py", line 24, in <module>
    from dm_control import mujoco
  File "/home/aj/miniconda3/envs/rlpyt/lib/python3.7/site-packages/dm_control/mujoco/__init__.py", line 18, in <module>
    from dm_control.mujoco.engine import action_spec
  File "/home/aj/miniconda3/envs/rlpyt/lib/python3.7/site-packages/dm_control/mujoco/engine.py", line 44, in <module>
    from dm_control import _render
  File "/home/aj/miniconda3/envs/rlpyt/lib/python3.7/site-packages/dm_control/_render/__init__.py", line 75, in <module>
    Renderer = import_func()
  File "/home/aj/miniconda3/envs/rlpyt/lib/python3.7/site-packages/dm_control/_render/__init__.py", line 36, in _import_egl
    from dm_control._render.pyopengl.egl_renderer import EGLContext
  File "/home/aj/miniconda3/envs/rlpyt/lib/python3.7/site-packages/dm_control/_render/pyopengl/egl_renderer.py", line 66, in <module>
    EGL_DISPLAY = create_initialized_headless_egl_display()
  File "/home/aj/miniconda3/envs/rlpyt/lib/python3.7/site-packages/dm_control/_render/pyopengl/egl_renderer.py", line 49, in create_initialized_headless_egl_display
    for device in EGL.eglQueryDevicesEXT():
  File "/home/aj/miniconda3/envs/rlpyt/lib/python3.7/site-packages/dm_control/_render/pyopengl/egl_ext.py", line 65, in eglQueryDevicesEXT
    success = _eglQueryDevicesEXT(max_devices, devices, num_devices)
ctypes.ArgumentError: argument 2: <class 'TypeError'>: expected LP_c_void_p instance instead of EGLDeviceEXT_pointer_Array_10

Thanks, A

[geyang]

@ajabri if X display is not available, you can use “osmesa” backend.

(for the interest of others: won’t work even if you install Xvfb and GLFW because they require X-display)

export MUJOCO_GL="osmesa"

Here is the full setup for a headless linux box with no built-in X display:

      export MUJOCO_GL=osmesa
      export MJLIB_PATH=$HOME/.mujoco/mujoco200/bin/libmujoco200.so
      export MJKEY_PATH=$HOME/.mujoco/mujoco200/mjkey.txt
      export LD_LIBRARY_PATH=$HOME/.mujoco/mujoco200/bin:$LD_LIBRARY_PATH
      export MUJOCO_PY_MJPRO_PATH=$HOME/.mujoco/mujoco200/
      export MUJOCO_PY_MJKEY_PATH=$HOME/.mujoco/mujoco200/mjkey.txt

@saran-t maybe we can add this to the documentation? 😃

[alimuldal]

I think this was due to an upstream change in PyOpenGL. In versions newer than 3.1.4, OpenGL.EGL has its own EGLDeviceEXT member (https://github.com/mcfletch/pyopengl/commit/38f4cc533b2ed3e85c585c4a4f00ed06f7aa6056), which overrides our assignment of EGLDeviceEXT = ctypes.c_void_p when we do the wildcard import on the last line. Consequently we end up with mismatching pointer types in _eglQueryDevicesEXT and in the body of eglQueryDevicesEXT. I’ll put together a fix.