Add configure method to Env, and support multiple displays in CartPole (#175)

* Add configure method to Env, and support multiple displays in CartPole

This allows people to pass runtime specification which doesn't affect
the environment semantics to environments created via `make`.

Also include an example of setting the display used for CartPole

* Provide full configure method

* Allow environments to require configuration

* Don't take arguments in make

gym/core.py

@@ -21,6 +21,7 @@ class Env(object):
         reset
         render
         close
+        configure
         seed
 
     When implementing an environment, override the following methods
@@ -30,6 +31,7 @@ class Env(object):
         _reset
         _render
         _close
+        _configure
         _seed
 
     And set the following attributes:
@@ -51,6 +53,7 @@ class Env(object):
         env._closed = False
         env._action_warned = False
         env._observation_warned = False
+        env._configured = False
 
         # Will be automatically set when creating an environment via 'make'
         env.spec = None
@@ -64,6 +67,9 @@ class Env(object):
     def _close(self):
         pass
 
+    def _configure(self):
+        pass
+
     # Set these in ALL subclasses
     action_space = None
     observation_space = None
@@ -127,6 +133,9 @@ class Env(object):
         Returns:
             observation (object): the initial observation of the space. (Initial reward is assumed to be 0.)
         """
+        if self.metadata.get('configure.required') and not self._configured:
+            raise error.Error("{} requires calling 'configure()' before 'reset()'".format(self))
+
         self.monitor._before_reset()
         observation = self._reset()
         self.monitor._after_reset(observation)
@@ -216,6 +225,18 @@ class Env(object):
         """
         return self._seed(seed)
 
+    def configure(self, *args, **kwargs):
+        """Provides runtime configuration to the environment.
+
+        This configuration should consist of data that tells your
+        environment how to run (such as an address of a remote server,
+        or path to your ImageNet data). It should not affect the
+        semantics of the environment.
+        """
+
+        self._configured = True
+        return self._configure(*args, **kwargs)
+
     def __del__(self):
         self.close()
 

gym/envs/classic_control/cartpole.py

@@ -43,6 +43,12 @@ class CartPoleEnv(gym.Env):
 
         self.steps_beyond_done = None
 
+        # Just need to initialize the relevant attributes
+        self._configure()
+
+    def _configure(self, display=None):
+        self.display = display
+
     def _seed(self, seed=None):
         self.np_random, seed = seeding.np_random(seed)
         return [seed]
@@ -108,7 +114,7 @@ class CartPoleEnv(gym.Env):
 
         if self.viewer is None:
             from gym.envs.classic_control import rendering
-            self.viewer = rendering.Viewer(screen_width, screen_height)
+            self.viewer = rendering.Viewer(screen_width, screen_height, display=self.display)
             l,r,t,b = -cartwidth/2, cartwidth/2, cartheight/2, -cartheight/2
             axleoffset =cartheight/4.0
             cart = rendering.FilledPolygon([(l,b), (l,t), (r,t), (r,b)])

gym/envs/classic_control/rendering.py

@@ -2,7 +2,9 @@
 2D rendering framework
 """
 from __future__ import division
-import os, sys
+import os
+import six
+import sys
 
 if "Apple" in sys.version:
     if 'DYLD_FALLBACK_LIBRARY_PATH' in os.environ:
@@ -27,11 +29,26 @@ import numpy as np
 
 RAD2DEG = 57.29577951308232
 
+def get_display(spec):
+    """Convert a display specification (such as :0) into an actual Display
+    object.
+
+    Pyglet only supports multiple Displays on Linux.
+    """
+    if spec is None:
+        return None
+    elif isinstance(spec, six.string_types):
+        return pyglet.canvas.Display(spec)
+    else:
+        raise error.Error('Invalid display specification: {}. (Must be a string like :0 or None.)'.format(spec))
+
 class Viewer(object):
-    def __init__(self, width, height):
+    def __init__(self, width, height, display=None):
+        display = get_display(display)
+
         self.width = width
         self.height = height
-        self.window = pyglet.window.Window(width=width, height=height)
+        self.window = pyglet.window.Window(width=width, height=height, display=display)
         self.window.on_close = self.window_closed_by_user
         self.geoms = []
         self.onetime_geoms = []
@@ -282,13 +299,14 @@ class Image(Geom):
 # ================================================================
 
 class SimpleImageViewer(object):
-    def __init__(self):
+    def __init__(self, display=None):
         self.window = None
         self.isopen = False
+        self.display = display
     def imshow(self, arr):
         if self.window is None:
             height, width, channels = arr.shape
-            self.window = pyglet.window.Window(width=width, height=height)
+            self.window = pyglet.window.Window(width=width, height=height, display=self.display)
             self.width = width
             self.height = height
             self.isopen = True

gym/envs/registration.py

@@ -2,6 +2,7 @@ import logging
 import pkg_resources
 import re
 import sys
+
 from gym import error
 
 logger = logging.getLogger(__name__)

requirements.txt

@@ -1,4 +1,4 @@
 numpy>=1.10.4
 requests>=2.0
 six
-pyglet
+pyglet>=1.2.0

setup.py

@@ -16,7 +16,7 @@ setup(name='gym',
                 if package.startswith('gym')],
       zip_safe=False,
       install_requires=[
-          'numpy>=1.10.4', 'requests>=2.0', 'six', 'pyglet',
+          'numpy>=1.10.4', 'requests>=2.0', 'six', 'pyglet>=1.2.0',
       ],
       extras_require={
           'all': ['atari_py>=0.0.17', 'Pillow', 'PyOpenGL',
@@ -28,7 +28,7 @@ setup(name='gym',
 
           # Environment-specific dependencies. Keep these in sync with
           # 'all'!
-          'atari': ['atari_py>=0.0.17', 'Pillow', 'pyglet', 'PyOpenGL'],
+          'atari': ['atari_py>=0.0.17', 'Pillow', 'PyOpenGL'],
           'board_game' : ['pachi-py>=0.0.19'],
           'box2d': ['box2d-py'],
           'classic_control': ['PyOpenGL'],