Added ability to drop/put down objects. Started work on PutNear env.

gym_minigrid/envs/__init__.py

@@ -4,4 +4,5 @@ from gym_minigrid.envs.multiroom import *
 from gym_minigrid.envs.fetch import *
 from gym_minigrid.envs.gotoobject import *
 from gym_minigrid.envs.gotodoor import *
+from gym_minigrid.envs.putnear import *
 from gym_minigrid.envs.fourroomqa import *

gym_minigrid/envs/putnear.py

@@ -0,0 +1,133 @@
+from gym_minigrid.minigrid import *
+from gym_minigrid.register import register
+
+class PutNearEnv(MiniGridEnv):
+    """
+    Environment in which the agent is instructed to place an object near
+    another object through a natural language string.
+    """
+
+    def __init__(
+        self,
+        size=6,
+        numObjs=2
+    ):
+        self.numObjs = numObjs
+        super().__init__(gridSize=size, maxSteps=5*size)
+
+        self.reward_range = (-1, 1)
+
+    def _genGrid(self, width, height):
+        # Create a grid surrounded by walls
+        grid = Grid(width, height)
+        for i in range(0, width):
+            grid.set(i, 0, Wall())
+            grid.set(i, height-1, Wall())
+        for j in range(0, height):
+            grid.set(0, j, Wall())
+            grid.set(width-1, j, Wall())
+
+        # Types and colors of objects we can generate
+        types = ['key', 'ball']
+        colors = list(COLORS.keys())
+
+        objs = []
+        objPos = []
+
+        def nearObj(p1):
+            for p2 in objPos:
+                dx = p1[0] - p2[0]
+                dy = p1[1] - p2[1]
+                if abs(dx) <= 1 and abs(dy) <= 1:
+                    return True
+            return False
+
+        # Until we have generated all the objects
+        while len(objs) < self.numObjs:
+            objType = self._randElem(types)
+            objColor = self._randElem(colors)
+
+            # If this object already exists, try again
+            if (objType, objColor) in objs:
+                continue
+
+            if objType == 'key':
+                obj = Key(objColor)
+            elif objType == 'ball':
+                obj = Ball(objColor)
+            elif objType == 'box':
+                obj = Box(objColor)
+
+            while True:
+                pos = (
+                    self._randInt(1, width - 1),
+                    self._randInt(1, height - 1)
+                )
+                if nearObj(pos):
+                    continue
+                if pos == self.startPos:
+                    continue
+                grid.set(*pos, obj)
+                break
+
+            objs.append((objType, objColor))
+            objPos.append(pos)
+
+        # Choose a random object to be moved up
+        objIdx = self._randInt(0, len(objs))
+        self.moveType, self.moveColor = objs[objIdx]
+        self.movePos = objPos[objIdx]
+
+
+
+
+
+        self.mission = 'put the %s %s near the Y' % (
+            self.moveColor,
+            self.moveType
+        )
+
+        return grid
+
+    def _observation(self, obs):
+        """
+        Encode observations
+        """
+
+        obs = {
+            'image': obs,
+            'mission': self.mission
+        }
+
+        return obs
+
+    def _reset(self):
+        obs = MiniGridEnv._reset(self)
+        return self._observation(obs)
+
+    def _step(self, action):
+        obs, reward, done, info = MiniGridEnv._step(self, action)
+
+        """
+        ax, ay = self.agentPos
+        tx, ty = self.targetPos
+
+        # Toggle/pickup action terminates the episode
+        if action == self.actions.toggle:
+            done = True
+
+        # Reward performing the wait action next to the target object
+        if action == self.actions.wait:
+            if abs(ax - tx) <= 1 and abs(ay - ty) <= 1:
+                reward = 1
+            done = self.waitEnds
+        """
+
+        obs = self._observation(obs)
+
+        return obs, reward, done, info
+
+register(
+    id='MiniGrid-PutNear-6x6-N2-v0',
+    entry_point='gym_minigrid.envs:PutNearEnv'
+)

gym_minigrid/minigrid.py

@@ -688,6 +688,9 @@ class MiniGridEnv(gym.Env):
                     self.grid.set(*objPos, None)
             elif cell:
                 cell.toggle(self, objPos)
+            elif self.carrying:
+                self.grid.set(*objPos, self.carrying)
+                self.carrying = None
 
         # Wait/do nothing
         elif action == self.actions.wait:

standalone.py

@@ -23,7 +23,13 @@ def main():
 
     # Load the gym environment
     env = gym.make(options.env_name)
-    env.reset()
+
+    def resetEnv():
+        env.reset()
+        if hasattr(env, 'mission'):
+            print('Mission: %s' % env.mission)
+
+    resetEnv()
 
     # Create a window to render into
     renderer = env.render('human')
@@ -41,7 +47,7 @@ def main():
         elif keyName == 'CTRL':
             action = env.actions.wait
         elif keyName == 'RETURN':
-            env.reset()
+            resetEnv()
         elif keyName == 'ESCAPE':
             sys.exit(0)
         else:
@@ -54,7 +60,7 @@ def main():
 
         if done:
             print('done!')
-            env.reset()
+            resetEnv()
 
     renderer.window.setKeyDownCb(keyDownCb)