def _setup_opengl_context()

in mujoco_py/mjrendercontext.pyx [0:0]


    def _setup_opengl_context(self, offscreen, device_id, opengl_backend, quiet=False):
        if opengl_backend is None and (not offscreen or sys.platform == 'darwin'):
            # default to glfw for onscreen viewing or mac (both offscreen/onscreen)
            opengl_backend = 'glfw'

        if opengl_backend == 'glfw':
            self.opengl_context = GlfwContext(offscreen=offscreen, quiet=quiet)
        else:
            if device_id < 0:
                if "GPUS" in os.environ:
                    device_id = os.environ["GPUS"]
                else:
                    device_id = os.getenv('CUDA_VISIBLE_DEVICES', '')
                if len(device_id) > 0:
                    device_id = int(device_id.split(',')[0])
                else:
                    # Sometimes env variable is an empty string.
                    device_id = 0
            self.opengl_context = OffscreenOpenGLContext(device_id)