Rename EGL_DEVICE_ID to MUJOCO_EGL_DEVICE_ID to be consistent with mujoco.

Fixes google-deepmind#345.

PiperOrigin-RevId: 493014875
Change-Id: I54babc50d9e5f1e970e9738bb3594c5ba1b55412

Author: saran-t

README.md

@@ -113,7 +113,7 @@ By default, `dm_control` will attempt to use GLFW first, then EGL, then OSMesa.
 You can also specify a particular backend to use by setting the `MUJOCO_GL=`
 environment variable to `"glfw"`, `"egl"`, or `"osmesa"`, respectively. When
 rendering with EGL, you can also specify which GPU to use for rendering by
-setting the environment variable `EGL_DEVICE_ID=` to the target GPU ID.
+setting the environment variable `MUJOCO_EGL_DEVICE_ID=` to the target GPU ID.
 
 ## Additional instructions for Homebrew users on macOS
 

dm_control/_render/pyopengl/egl_renderer.py

@@ -43,14 +43,14 @@
 def create_initialized_headless_egl_display():
   """Creates an initialized EGL display directly on a device."""
   all_devices = EGL.eglQueryDevicesEXT()
-  selected_device = os.environ.get('EGL_DEVICE_ID', None)
+  selected_device = os.environ.get('MUJOCO_EGL_DEVICE_ID', None)
   if selected_device is None:
     candidates = all_devices
   else:
     device_idx = int(selected_device)
     if not 0 <= device_idx < len(all_devices):
       raise RuntimeError(
-          f'EGL_DEVICE_ID must be an integer between 0 and '
+          f'MUJOCO_EGL_DEVICE_ID must be an integer between 0 and '
           f'{len(all_devices) - 1} (inclusive), got {device_idx}.')
     candidates = all_devices[device_idx:device_idx + 1]
   for device in candidates: