训练新版

Env/bc_env.py

@@ -51,10 +51,8 @@ class BCScenarioEnv(MultiAgentScenarioEnv):
         return car_birth_info_list, background_vehicles, obj_to_clean
 
     def _spawn_background_vehicles(self):
-        """Spawn static background vehicles so they appear in active_agents and thus in obs (same as ExpertReplayEnv)."""
+        """Spawn all static background vehicles once at reset (no show_time filter; same as ExpertReplayEnv)."""
         for sid, car in self.background_vehicles.items():
-            if car["show_time"] != self.round:
-                continue
             bg_id = f"bg_{car['id']}"
             if bg_id in self.engine.agent_manager.active_agents:
                 continue
@@ -70,24 +68,12 @@ class BCScenarioEnv(MultiAgentScenarioEnv):
             )
             v.set_velocity([0, 0])
             self.engine.agent_manager.active_agents[bg_id] = v
-            v.valid_mask = car["valid"]
-            v.start_t = car["show_time"]
+            v.valid_mask = car.get("valid")
+            v.start_t = car.get("show_time")
 
     def _update_background_vehicles(self):
-        self._spawn_background_vehicles()
-        to_remove = []
-        objects_to_clear = []
-        for aid, v in self.engine.agent_manager.active_agents.items():
-            if not aid.startswith("bg_"):
-                continue
-            if hasattr(v, "valid_mask"):
-                if self.round >= len(v.valid_mask) or not v.valid_mask[self.round]:
-                    to_remove.append(aid)
-                    objects_to_clear.append(v)
-        for aid in to_remove:
-            self.engine.agent_manager.active_agents.pop(aid, None)
-        if objects_to_clear:
-            self.engine.clear_objects([v.id for v in objects_to_clear])
+        # Static vehicles are spawned once at init and never removed.
+        pass
 
     def step(self, action_dict):
         self.round += 1

Env/expert_replay_env.py

@@ -97,7 +97,7 @@ class ExpertReplayEnv(MultiAgentScenarioEnv):
         # We covered most of it.
         
         self._spawn_controlled_agents()
-        self._spawn_background_vehicles() # Initial spawn for background
+        self._spawn_all_background_vehicles_at_init()
 
         # Ensure SDC/ego is moved to the correct initial expert state.
         if self.replay_sdc:
@@ -114,87 +114,33 @@ class ExpertReplayEnv(MultiAgentScenarioEnv):
         
         return self._get_all_obs()
 
-    def _spawn_background_vehicles(self):
-        # Spawn static/background vehicles
-        # Since they are static, we might just spawn them once if their show_time is 0
-        # But Waymo tracks have valid bits, they might appear/disappear.
-        # For optimization, if they are truly static (never move), we just spawn them when show_time matches.
-        
-        # We need to track spawned background vehicles to remove them if they become invalid?
-        # Since we defined them as "static", they probably stay put. 
-        # But validity might change (e.g. late spawn).
-        
-        # For simplicity in this step, let's just iterate and spawn if time matches
+    def _spawn_all_background_vehicles_at_init(self):
+        """Spawn all static background vehicles once at reset (no show_time filter; no removal by valid)."""
         for sid, car in self.background_vehicles.items():
-            if car['show_time'] == self.round:
-                # Spawn as a Traffic Vehicle (not PolicyVehicle), or just a static object?
-                # Using DefaultVehicle is fine, but don't add to controlled_agents
-                
-                # Check duplication
-                bg_id = f"bg_{car['id']}"
-                # if bg_id in self.engine.obj_to_id: # obj_to_id might not be available in all versions
-                if bg_id in self.engine.agent_manager.active_agents:
-                    continue
-                    
-                vehicle_config = {}
-                if 'length' in car and 'width' in car:
-                     vehicle_config = {
-                         "length": car['length'],
-                         "width": car['width']
-                     }
-
-                v = self.engine.spawn_object(
-                    DefaultVehicle,
-                    name=bg_id,
-                    vehicle_config=vehicle_config,
-                    position=car['begin'],
-                    heading=car['heading']
-                )
-                
-                # Set color to grey/dark to indicate background
-                v.set_velocity([0, 0])
-                # Maybe set color? MetaDrive vehicles random color.
-                # v.set_color(...) if supported
-                
-                # Register as an active object but NOT controlled agent
-                # The engine manages it. 
-                # CRITICAL: We need it in self.engine.agent_manager.active_agents for Observation?
-                # If we want it to be seen by Lidar/Observation, it needs to be an "agent" or "traffic".
-                # DefaultVehicle spawned this way is just an object.
-                # We should add it to traffic manager? Or just leave it as object?
-                # MultiAgentScenarioEnv._get_all_obs iterates self.engine.agent_manager.active_agents
-                
-                # If we want it in observation, we must add it to active_agents OR iterate over all objects.
-                # Adding to active_agents is easier for compatibility.
-                self.engine.agent_manager.active_agents[bg_id] = v
-                
-                # Store valid mask to remove it later if needed?
-                v.valid_mask = car['valid']
-                v.start_t = car['show_time']
+            bg_id = f"bg_{car['id']}"
+            if bg_id in self.engine.agent_manager.active_agents:
+                continue
+            vehicle_config = {}
+            if 'length' in car and 'width' in car:
+                vehicle_config = {
+                    "length": car['length'],
+                    "width": car['width']
+                }
+            v = self.engine.spawn_object(
+                DefaultVehicle,
+                name=bg_id,
+                vehicle_config=vehicle_config,
+                position=car['begin'],
+                heading=car['heading']
+            )
+            v.set_velocity([0, 0])
+            self.engine.agent_manager.active_agents[bg_id] = v
+            v.valid_mask = car.get('valid')
+            v.start_t = car['show_time']
 
     def _update_background_vehicles(self):
-        # Remove background vehicles if they become invalid
-        # Or spawn new ones
-        self._spawn_background_vehicles()
-        
-        # Check validity for existing
-        to_remove = []
-        objects_to_clear = []
-        
-        for aid, v in self.engine.agent_manager.active_agents.items():
-            if aid.startswith("bg_"):
-                # Check validity
-                if hasattr(v, 'valid_mask'):
-                    curr_step = self.round
-                    if curr_step >= len(v.valid_mask) or not v.valid_mask[curr_step]:
-                        to_remove.append(aid)
-                        objects_to_clear.append(v)
-        
-        for aid in to_remove:
-             self.engine.agent_manager.active_agents.pop(aid, None)
-             
-        if objects_to_clear:
-            self.engine.clear_objects([v.id for v in objects_to_clear])
+        # Static vehicles are spawned once at init and never removed (no spawn/remove by show_time or valid).
+        pass
 
     def _spawn_controlled_agents(self):
         for car in self.car_birth_info_list:

Env/scenario_env.py

@@ -81,6 +81,11 @@ class MultiAgentScenarioEnv(ScenarioEnv):
         if self.engine is None:
             raise ValueError("Broken MetaDrive instance.")
 
+        # 注意：_build_birth_lists_from_traffic() 在 engine.reset() 之前执行，读的是当前 engine 的
+        # current_traffic_data 与 map_manager.current_map。若复用同一 env 连续 reset(0)、reset(1)，
+        # MetaDrive 可能已按 seed 更新了 traffic 为 scenario 1，但 map 仍为 scenario 0（在 engine.reset() 才切图），
+        # 导致 is_on_lane( scenario_1 车位, scenario_0 地图 ) 全为 False → 全部 off_lane → 0 受控车。
+        # 因此多场景时应“每个 scenario 单独建 env”（start_scenario_index=i, num_scenarios=1）再 reset(seed=i)。
         self.background_vehicles = getattr(self, "background_vehicles", {})
         self.car_birth_info_list, self.background_vehicles, _obj_to_clean = self._build_birth_lists_from_traffic()
         for scenario_id in _obj_to_clean:

Env/utils.py

@@ -5,6 +5,86 @@ import random
 from metadrive.type import MetaDriveType
 
 
+def _static_obbs_overlap(car_a, car_b):
+    """
+    Check if two static vehicle OBBs overlap (2D SAT).
+    car_a, car_b: dicts with "begin" (x, y), "heading" (rad), "length", "width".
+    begin is center; half-extents are length/2, width/2.
+    """
+    def _get_corners(car):
+        cx, cy = car["begin"][0], car["begin"][1]
+        h = float(car["heading"])
+        L2 = float(car["length"]) / 2.0
+        W2 = float(car["width"]) / 2.0
+        ux, uy = np.cos(h), np.sin(h)
+        vx, vy = -np.sin(h), np.cos(h)
+        return np.array([
+            [cx + L2 * ux + W2 * vx, cy + L2 * uy + W2 * vy],
+            [cx + L2 * ux - W2 * vx, cy + L2 * uy - W2 * vy],
+            [cx - L2 * ux - W2 * vx, cy - L2 * uy - W2 * vy],
+            [cx - L2 * ux + W2 * vx, cy - L2 * uy + W2 * vy],
+        ])
+
+    def _get_axes(car):
+        h = float(car["heading"])
+        return [
+            np.array([np.cos(h), np.sin(h)]),
+            np.array([-np.sin(h), np.cos(h)]),
+        ]
+
+    corners_a = _get_corners(car_a)
+    corners_b = _get_corners(car_b)
+    axes = _get_axes(car_a) + _get_axes(car_b)
+
+    for axis in axes:
+        proj_a = corners_a @ axis
+        proj_b = corners_b @ axis
+        min_a, max_a = proj_a.min(), proj_a.max()
+        min_b, max_b = proj_b.min(), proj_b.max()
+        if max_a < min_b or max_b < min_a:
+            return False
+    return True
+
+
+def _deduplicate_background_by_collision(background_vehicles):
+    """
+    Merge static tracks that collide (same physical vehicle). Build collision graph,
+    find connected components, keep one representative per component (min show_time, then scenario_id).
+    """
+    if not background_vehicles:
+        return background_vehicles
+    items = list(background_vehicles.items())
+    n = len(items)
+    # Build adjacency by index
+    parent = list(range(n))
+
+    def find(i):
+        if parent[i] != i:
+            parent[i] = find(parent[i])
+        return parent[i]
+
+    def union(i, j):
+        pi, pj = find(i), find(j)
+        if pi != pj:
+            parent[pi] = pj
+
+    for i in range(n):
+        for j in range(i + 1, n):
+            if _static_obbs_overlap(items[i][1], items[j][1]):
+                union(i, j)
+
+    # Representative per component: index with min (show_time, scenario_id)
+    comp_rep = {}
+    for i in range(n):
+        r = find(i)
+        sid, car = items[i][0], items[i][1]
+        key = (car.get("show_time", 0), sid)
+        if r not in comp_rep or key < comp_rep[r][0]:
+            comp_rep[r] = (key, sid, car)
+
+    return {sid: car for (_, sid, car) in comp_rep.values()}
+
+
 def is_on_lane(pos, map_manager, threshold=2.0):
     """Check if a position is on a valid lane (within lateral tolerance)."""
     if map_manager is None or map_manager.current_map is None:
@@ -31,6 +111,7 @@ def filter_traffic_tracks_to_birth_lists(
     static_displacement_threshold=5.0,
     static_speed_threshold=1.0,
     return_stats=False,
+    deduplicate_static_by_collision=True,
 ):
     """
     Filter traffic tracks into controlled (car_birth_info_list) and background lists.
@@ -127,6 +208,9 @@ def filter_traffic_tracks_to_birth_lists(
             "width": track["state"]["width"][first_show],
         })
 
+    if deduplicate_static_by_collision and background_vehicles:
+        background_vehicles = _deduplicate_background_by_collision(background_vehicles)
+
     if return_stats:
         stats = {
             "n_total": n_total,