Add termination condition based on percentage of visited tiles for Car Racing

gymnasium/envs/box2d/car_racing.py

@@ -87,20 +87,21 @@ def _contact(self, contact, begin):
         tile.color[:] = self.env.road_color
         if not obj or "tiles" not in obj.__dict__:
             return
+
+        # Lap is considered completed if enough % of the track was covered
+        if (
+            tile.idx == 0
+            and self.env.tile_visited_count / len(self.env.track)
+            > self.lap_complete_percent
+        ):
+            self.env.new_lap = True
+
         if begin:
             obj.tiles.add(tile)
             if not tile.road_visited:
                 tile.road_visited = True
                 self.env.reward += 1000.0 / len(self.env.track)
                 self.env.tile_visited_count += 1
-
-                # Lap is considered completed if enough % of the track was covered
-                if (
-                    tile.idx == 0
-                    and self.env.tile_visited_count / len(self.env.track)
-                    > self.lap_complete_percent
-                ):
-                    self.env.new_lap = True
         else:
             obj.tiles.remove(tile)
 
@@ -146,7 +147,7 @@ class CarRacing(gym.Env, EzPickle):
     The car starts at rest in the center of the road.
 
     ## Episode Termination
-    The episode finishes when all the tiles are visited. The car can also go outside the playfield -
+    The episode finishes when the car reaches the end of the circuit or the time limit is reached. The car can also go outside the playfield -
      that is, far off the track, in which case it will receive -100 reward and die.
 
     ## Arguments
@@ -190,6 +191,8 @@ class CarRacing(gym.Env, EzPickle):
     ```
 
     ## Version History
+    - v4: The episode will now terminate upon completing the lap, regardless of the number of tiles visited
+    - v3: Improved RNG handling with seed=-1; fixed bugs in environment checking and Box shape inference; minor fixes, including typos and dependency management.
     - v2: Change truncation to termination when finishing the lap (1.0.0)
     - v1: Change track completion logic and add domain randomization (0.24.0)
     - v0: Original version