from minigrid.core.constants import COLOR_NAMES, DIR_TO_VEC
from minigrid.core.mission import MissionSpace
from minigrid.core.roomgrid import RoomGrid
from minigrid.core.world_object import Ball, Box, Key
class ObstructedMazeEnv(RoomGrid):
"""
### Description
The agent has to pick up a box which is placed in a corner of a 3x3 maze.
The doors are locked, the keys are hidden in boxes and doors are obstructed
by balls. This environment can be solved without relying on language.
### Mission Space
"pick up the {COLOR_NAMES[0]} ball"
### Action Space
| Num | Name | Action |
|-----|--------------|---------------------------|
| 0 | left | Turn left |
| 1 | right | Turn right |
| 2 | forward | Move forward |
| 3 | pickup | Pick up an object |
| 4 | drop | Unused |
| 5 | toggle | Toggle/activate an object |
| 6 | done | Unused |
### Observation Encoding
- Each tile is encoded as a 3 dimensional tuple:
`(OBJECT_IDX, COLOR_IDX, STATE)`
- `OBJECT_TO_IDX` and `COLOR_TO_IDX` mapping can be found in
[minigrid/minigrid.py](minigrid/minigrid.py)
- `STATE` refers to the door state with 0=open, 1=closed and 2=locked
### Rewards
A reward of '1' is given for success, and '0' for failure.
### Termination
The episode ends if any one of the following conditions is met:
1. The agent picks up the blue ball.
2. Timeout (see `max_steps`).
### Registered Configurations
"NDl" are the number of doors locked.
"h" if the key is hidden in a box.
"b" if the door is obstructed by a ball.
"Q" number of quarters that will have doors and keys out of the 9 that the
map already has.
"Full" 3x3 maze with "h" and "b" options.
- `MiniGrid-ObstructedMaze-1Dl-v0`
- `MiniGrid-ObstructedMaze-1Dlh-v0`
- `MiniGrid-ObstructedMaze-1Dlhb-v0`
- `MiniGrid-ObstructedMaze-2Dl-v0`
- `MiniGrid-ObstructedMaze-2Dlh-v0`
- `MiniGrid-ObstructedMaze-2Dlhb-v0`
- `MiniGrid-ObstructedMaze-1Q-v0`
- `MiniGrid-ObstructedMaze-2Q-v0`
- `MiniGrid-ObstructedMaze-Full-v0`
"""
def __init__(self, num_rows, num_cols, num_rooms_visited, **kwargs):
room_size = 6
max_steps = 4 * num_rooms_visited * room_size**2
mission_space = MissionSpace(
mission_func=lambda: f"pick up the {COLOR_NAMES[0]} ball",
)
super().__init__(
mission_space=mission_space,
room_size=room_size,
num_rows=num_rows,
num_cols=num_cols,
max_steps=max_steps,
**kwargs,
)
self.obj = Ball() # initialize the obj attribute, that will be changed later on
def _gen_grid(self, width, height):
super()._gen_grid(width, height)
# Define all possible colors for doors
self.door_colors = self._rand_subset(COLOR_NAMES, len(COLOR_NAMES))
# Define the color of the ball to pick up
self.ball_to_find_color = COLOR_NAMES[0]
# Define the color of the balls that obstruct doors
self.blocking_ball_color = COLOR_NAMES[1]
# Define the color of boxes in which keys are hidden
self.box_color = COLOR_NAMES[2]
self.mission = "pick up the %s ball" % self.ball_to_find_color
def step(self, action):
obs, reward, terminated, truncated, info = super().step(action)
if action == self.actions.pickup:
if self.carrying and self.carrying == self.obj:
reward = self._reward()
terminated = True
return obs, reward, terminated, truncated, info
def add_door(
self,
i,
j,
door_idx=0,
color=None,
locked=False,
key_in_box=False,
blocked=False,
):
"""
Add a door. If the door must be locked, it also adds the key.
If the key must be hidden, it is put in a box. If the door must
be obstructed, it adds a ball in front of the door.
"""
door, door_pos = super().add_door(i, j, door_idx, color, locked=locked)
if blocked:
vec = DIR_TO_VEC[door_idx]
blocking_ball = Ball(self.blocking_ball_color) if blocked else None
self.grid.set(door_pos[0] - vec[0], door_pos[1] - vec[1], blocking_ball)
if locked:
obj = Key(door.color)
if key_in_box:
box = Box(self.box_color)
box.contains = obj
obj = box
self.place_in_room(i, j, obj)
return door, door_pos
class ObstructedMaze_1Dlhb(ObstructedMazeEnv):
"""
A blue ball is hidden in a 2x1 maze. A locked door separates
rooms. Doors are obstructed by a ball and keys are hidden in boxes.
"""
def __init__(self, key_in_box=True, blocked=True, **kwargs):
self.key_in_box = key_in_box
self.blocked = blocked
super().__init__(num_rows=1, num_cols=2, num_rooms_visited=2, **kwargs)
def _gen_grid(self, width, height):
super()._gen_grid(width, height)
self.add_door(
0,
0,
door_idx=0,
color=self.door_colors[0],
locked=True,
key_in_box=self.key_in_box,
blocked=self.blocked,
)
self.obj, _ = self.add_object(1, 0, "ball", color=self.ball_to_find_color)
self.place_agent(0, 0)
class ObstructedMaze_Full(ObstructedMazeEnv):
"""
A blue ball is hidden in one of the 4 corners of a 3x3 maze. Doors
are locked, doors are obstructed by a ball and keys are hidden in
boxes.
"""
def __init__(
self,
agent_room=(1, 1),
key_in_box=True,
blocked=True,
num_quarters=4,
num_rooms_visited=25,
**kwargs,
):
self.agent_room = agent_room
self.key_in_box = key_in_box
self.blocked = blocked
self.num_quarters = num_quarters
super().__init__(
num_rows=3, num_cols=3, num_rooms_visited=num_rooms_visited, **kwargs
)
def _gen_grid(self, width, height):
super()._gen_grid(width, height)
middle_room = (1, 1)
# Define positions of "side rooms" i.e. rooms that are neither
# corners nor the center.
side_rooms = [(2, 1), (1, 2), (0, 1), (1, 0)][: self.num_quarters]
for i in range(len(side_rooms)):
side_room = side_rooms[i]
# Add a door between the center room and the side room
self.add_door(
*middle_room, door_idx=i, color=self.door_colors[i], locked=False
)
for k in [-1, 1]:
# Add a door to each side of the side room
self.add_door(
*side_room,
locked=True,
door_idx=(i + k) % 4,
color=self.door_colors[(i + k) % len(self.door_colors)],
key_in_box=self.key_in_box,
blocked=self.blocked,
)
corners = [(2, 0), (2, 2), (0, 2), (0, 0)][: self.num_quarters]
ball_room = self._rand_elem(corners)
self.obj, _ = self.add_object(
ball_room[0], ball_room[1], "ball", color=self.ball_to_find_color
)
self.place_agent(*self.agent_room)
class ObstructedMaze_2Dl(ObstructedMaze_Full):
def __init__(self, **kwargs):
super().__init__((2, 1), False, False, 1, 4, **kwargs)
class ObstructedMaze_2Dlh(ObstructedMaze_Full):
def __init__(self, **kwargs):
super().__init__((2, 1), True, False, 1, 4, **kwargs)
class ObstructedMaze_2Dlhb(ObstructedMaze_Full):
def __init__(self, **kwargs):
super().__init__((2, 1), True, True, 1, 4, **kwargs)