I meet a error

[Charele]

I start the gym_http_server,
when I run example_agent.py,I get the error message on server console

Server starting at: http://127.0.0.1:5000

• Serving Flask app "gym_http_server" (lazy loading)
• Environment: production
  WARNING: Do not use the development server in a production environment.
  Use a production WSGI server instead.
• Debug mode: off
  �[33mWARN: gym.spaces.Box autodetected dtype as <type 'numpy.float32'>. Please provide explicit dtype.�[0m
  [2018-08-25 19:59:14,161] ERROR in app: Exception on /v1/envs/f8c9a1cd/step/ [POST]
  Traceback (most recent call last):
  File "C:\Anaconda2\lib\site-packages\flask\app.py", line 2292, in wsgi_app
  response = self.full_dispatch_request()
  File "C:\Anaconda2\lib\site-packages\flask\app.py", line 1815, in full_dispatch_request
  rv = self.handle_user_exception(e)
  File "C:\Anaconda2\lib\site-packages\flask\app.py", line 1718, in handle_user_exception
  reraise(exc_type, exc_value, tb)
  File "C:\Anaconda2\lib\site-packages\flask\app.py", line 1813, in full_dispatch_request
  rv = self.dispatch_request()
  File "C:\Anaconda2\lib\site-packages\flask\app.py", line 1799, in dispatch_request
  return self.view_functionsrule.endpoint
  File "gym_http_server.py", line 258, in env_step
  [obs_jsonable, reward, done, info] = envs.step(instance_id, action, render)
  File "gym_http_server.py", line 71, in step
  env.render()
  File "C:\Anaconda2\lib\site-packages\gym\core.py", line 284, in render
  return self.env.render(mode)
  File "C:\Anaconda2\lib\site-packages\gym\core.py", line 284, in render
  return self.env.render(mode)
  File "C:\Anaconda2\lib\site-packages\gym\envs\classic_control\cartpole.py", line 137, in render
  return self.viewer.render(return_rgb_array = mode=='rgb_array')
  File "C:\Anaconda2\lib\site-packages\gym\envs\classic_control\rendering.py", line 82, in render
  glClearColor(1,1,1,1)
  File "C:\Anaconda2\lib\site-packages\pyglet\gl\lib.py", line 105, in errcheck
  raise GLException(msg)

[parthopdas]

This issues appears to be on windows only.

It seems to due to pyglet attempting to access opengl state across multiple threads: first thread creating the viewer (initializing opengl through pyglet) and a different thread (from the next step) calling render which then calls opengl again.

can you try the following and see if it works for you - considering use case, i think is a good enough fix.

the above fix works for me.