Implement missing driving domain actions in MetaDrive interface

.coveragerc

@@ -5,7 +5,6 @@ omit =
     src/scenic/simulators/carla/*
     src/scenic/simulators/gta/*
     src/scenic/simulators/lgsvl/*
-    src/scenic/simulators/metadrive/*
     src/scenic/simulators/webots/*
     src/scenic/simulators/xplane/*
 

src/scenic/domains/driving/actions.py

@@ -122,6 +122,8 @@ def canBeTakenBy(self, agent):
 class SetThrottleAction(SteeringAction):
     """Set the throttle.
 
+    The throttle setting will remain constant until this action is taken again.
+
     Arguments:
         throttle: Throttle value between 0 and 1.
     """
@@ -138,6 +140,8 @@ def applyTo(self, obj, sim):
 class SetSteerAction(SteeringAction):
     """Set the steering 'angle'.
 
+    The steering setting will remain constant until this action is taken again.
+
     Arguments:
         steer: Steering 'angle' between -1 and 1. Positive values steer to the right.
     """
@@ -154,6 +158,8 @@ def applyTo(self, obj, sim):
 class SetBrakeAction(SteeringAction):
     """Set the amount of brake.
 
+    The brake setting will remain constant until this action is taken again.
+
     Arguments:
         brake: Amount of braking between 0 and 1.
     """
@@ -170,6 +176,8 @@ def applyTo(self, obj, sim):
 class SetHandBrakeAction(SteeringAction):
     """Set or release the hand brake.
 
+    The handbrake setting will remain constant until this action is taken again.
+
     Arguments:
         handBrake: Whether or not the hand brake is set.
     """
@@ -186,6 +194,8 @@ def applyTo(self, obj, sim):
 class SetReverseAction(SteeringAction):
     """Engage or release reverse gear.
 
+    The reverse setting will remain constant until this action is taken again.
+
     Arguments:
         reverse: Whether or not the car is in reverse.
     """

src/scenic/simulators/metadrive/model.scenic

@@ -44,7 +44,7 @@ from scenic.simulators.metadrive.sensors import MetaDriveSSSensor as SSSensor
 
 try:
     from scenic.simulators.metadrive.simulator import MetaDriveSimulator
-    from scenic.simulators.metadrive.utils import scenicToMetaDriveHeading
+    from scenic.simulators.metadrive.utils import scenicToMetaDriveHeading, scenicToMetaDrivePosition
 except ModuleNotFoundError:
     # for convenience when testing without the metadrive package
     from scenic.core.simulators import SimulatorInterfaceWarning
@@ -117,30 +117,55 @@ class MetaDriveActor(DrivingObject):
     """
     metaDriveActor: None
 
+    def setPosition(self, pos, elevation):
+        position = scenicToMetaDrivePosition(pos, simulation().scenic_offset)
+        self.metaDriveActor.set_position(position)
+
+    def setVelocity(self, vel):
+        self.metaDriveActor.set_velocity(vel)
+
+
 class Vehicle(Vehicle, Steers, MetaDriveActor):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
-        self._control = {"steering": 0, "throttle": 0, "brake": 0}
-
-    def _reset_control(self):
-        self._control = {"steering": 0, "throttle": 0, "brake": 0}
+        self._control = {"steer": 0.0, "throttle": 0.0, "brake": 0.0}
+        self._reverse = False
+        self._handbrake = False
 
     def setThrottle(self, throttle):
         self._control["throttle"] = throttle
 
     def setSteering(self, steering):
-        self._control["steering"] = steering
+        self._control["steer"] = steering
 
     def setBraking(self, braking):
         self._control["brake"] = braking
 
-    def _collect_action(self):
-        steering = -self._control["steering"]  # Invert the steering to match MetaDrive's convention
-        action = [
-            steering,
-            self._control["throttle"] - self._control["brake"],
-        ]
-        return action
+    def setReverse(self, reverse):
+        self._reverse = reverse
+
+    def setHandbrake(self, handbrake):
+        self._handbrake = handbrake
+
+    def _prepare_action(self):
+        # MetaDrive uses the opposite convention: positive steer turns left
+        steer = -self._control["steer"]
+
+        # Handbrake overrides everything: disable reverse, full brake.
+        if self._handbrake:
+            self.metaDriveActor.enable_reverse = False
+            return [steer, -1.0]
+
+        # MetaDrive uses a single combined throttle/brake value
+        throttle_brake = self._control["throttle"] - self._control["brake"]
+
+        # Enable reverse only if requested AND there’s forward drive effort.
+        enable_reverse = self._reverse and (throttle_brake > 0.0)
+        self.metaDriveActor.enable_reverse = enable_reverse
+        if enable_reverse:
+            throttle_brake = -throttle_brake  # negative drives backward
+        return [steer, throttle_brake]
+
 
 class Car(Vehicle):
     @property

src/scenic/simulators/metadrive/simulator.py

@@ -274,9 +274,8 @@ def executeActions(self, allActions):
             if obj is self.objects[0]:  # Skip ego vehicle (it is handled separately)
                 continue
             if obj.isVehicle:
-                action = obj._collect_action()
+                action = obj._prepare_action()
                 obj.metaDriveActor.before_step(action)
-                obj._reset_control()
             else:
                 # For Pedestrians
                 if obj._walking_direction is None:
@@ -294,9 +293,8 @@ def step(self):
 
         # Special handling for the ego vehicle
         ego_obj = self.objects[0]
-        action = ego_obj._collect_action()
-        self.client.step(action)  # Apply action in the simulator
-        ego_obj._reset_control()
+        action = ego_obj._prepare_action()
+        self.client.step(action)
 
         # Render the scene in 2D if needed
         if self.render and not self.render3D:

tests/simulators/metadrive/test_metadrive.py

@@ -1,3 +1,4 @@
+import math
 import os
 from urllib.error import URLError
 
@@ -58,11 +59,14 @@ def test_pickle(loadLocalScenario):
 def getMetadriveSimulator(getAssetPath):
     base = getAssetPath("maps/CARLA")
 
-    def _getMetadriveSimulator(town, *, render=False, render3D=False):
+    def _getMetadriveSimulator(town, *, render=False, render3D=False, **kwargs):
         openDrivePath = os.path.join(base, f"{town}.xodr")
         sumoPath = os.path.join(base, f"{town}.net.xml")
         simulator = MetaDriveSimulator(
-            sumo_map=sumoPath, render=render, render3D=render3D
+            sumo_map=sumoPath,
+            render=render,
+            render3D=render3D,
+            **kwargs,
         )
         return simulator, openDrivePath, sumoPath
 
@@ -124,39 +128,103 @@ def test_brake(getMetadriveSimulator):
     assert finalSpeed == pytest.approx(0.0, abs=1e-1)
 
 
-def test_pedestrian_movement(getMetadriveSimulator):
+def test_reverse_and_brake(getMetadriveSimulator):
     simulator, openDrivePath, sumoPath = getMetadriveSimulator("Town01")
     code = f"""
         param map = r'{openDrivePath}'
         param sumo_map = r'{sumoPath}'
 
         model scenic.simulators.metadrive.model
 
-        behavior WalkForward():
+        behavior Reverse():
             while True:
-                take SetWalkingDirectionAction(self.heading), SetWalkingSpeedAction(0.5)
+                take SetReverseAction(True), SetThrottleAction(1), SetBrakeAction(0)
 
-        behavior StopWalking():
+        behavior Brake():
             while True:
-                take SetWalkingSpeedAction(0)
+                take SetThrottleAction(0), SetBrakeAction(1)
 
-        behavior WalkThenStop():
-            do WalkForward() for 2 steps
-            do StopWalking() for 2 steps
+        behavior ReverseThenBrake():
+            do Reverse() for 3 steps
+            do Brake() for 10 steps
 
-        ego = new Car at (30, 2)
-        pedestrian = new Pedestrian at (50, 6), with behavior WalkThenStop
+        ego = new Car at (369, -326), with behavior ReverseThenBrake
 
-        record pedestrian.position as Pos
-        terminate after 4 steps
+        record initial ego.heading as Heading
+        record ego.velocity as Vel
+        record final ego.speed as Speed
+
+        terminate after 13 steps
     """
     scenario = compileScenic(code, mode2D=True)
     scene = sampleScene(scenario)
     simulation = simulator.simulate(scene)
-    series = simulation.result.records["Pos"]
-    initialPos = series[0][1]
-    finalPos = series[-1][1]
-    assert initialPos != finalPos
+
+    h = simulation.result.records["Heading"]
+    fwd = (-math.sin(h), math.cos(h))
+    vx, vy, _ = simulation.result.records["Vel"][2][1]
+    proj = vx * fwd[0] + vy * fwd[1]
+    assert proj < -0.02, f"Expected reverse velocity (negative proj), got {proj}"
+
+    finalSpeed = simulation.result.records["Speed"]
+    assert finalSpeed == pytest.approx(0.0, abs=0.5)
+
+
+def test_handbrake(getMetadriveSimulator):
+    simulator, openDrivePath, sumoPath = getMetadriveSimulator("Town01")
+    code = f"""
+        param map = r'{openDrivePath}'
+        param sumo_map = r'{sumoPath}'
+
+        model scenic.simulators.metadrive.model
+
+        behavior HandbrakeAndThrottle():
+            while True:
+                take SetHandBrakeAction(True), SetThrottleAction(1)
+
+        ego = new Car at (369, -326), with behavior HandbrakeAndThrottle
+        record initial ego.position as InitialPos
+        record final ego.position as FinalPos
+        record final ego.speed as Speed
+        terminate after 6 steps
+    """
+    scenario = compileScenic(code, mode2D=True)
+    scene = sampleScene(scenario)
+    simulation = simulator.simulate(scene)
+
+    p0 = simulation.result.records["InitialPos"]
+    p1 = simulation.result.records["FinalPos"]
+    finalSpeed = simulation.result.records["Speed"]
+
+    assert p0 == pytest.approx(p1, abs=0.05)
+    assert finalSpeed == pytest.approx(0.0, abs=0.1)
+
+
+def test_set_position(getMetadriveSimulator):
+    simulator, openDrivePath, sumoPath = getMetadriveSimulator("Town01")
+    code = f"""
+        param map = r'{openDrivePath}'
+        param sumo_map = r'{sumoPath}'
+
+        model scenic.simulators.metadrive.model
+
+        behavior Teleport():
+            wait
+            take SetPositionAction(Vector(120, -56))
+
+        ego = new Car at (30, 2), with behavior Teleport
+        record initial ego.position as InitialPos
+        record final ego.position as FinalPos
+        terminate after 2 steps
+    """
+    scenario = compileScenic(code, mode2D=True)
+    scene = sampleScene(scenario)
+    simulation = simulator.simulate(scene)
+    p0 = simulation.result.records["InitialPos"]
+    p1 = simulation.result.records["FinalPos"]
+
+    assert p0 != p1
+    assert p1 == pytest.approx((120, -56, 0), abs=0.01)
 
 
 def test_initial_velocity_movement(getMetadriveSimulator):
@@ -182,6 +250,41 @@ def test_initial_velocity_movement(getMetadriveSimulator):
     assert dx < -0.1, f"Expected car to move west (negative dx), but got dx = {dx}"
 
 
+def test_pedestrian_movement(getMetadriveSimulator):
+    simulator, openDrivePath, sumoPath = getMetadriveSimulator("Town01")
+    code = f"""
+        param map = r'{openDrivePath}'
+        param sumo_map = r'{sumoPath}'
+
+        model scenic.simulators.metadrive.model
+
+        behavior WalkForward():
+            while True:
+                take SetWalkingDirectionAction(self.heading), SetWalkingSpeedAction(0.5)
+
+        behavior StopWalking():
+            while True:
+                take SetWalkingSpeedAction(0)
+
+        behavior WalkThenStop():
+            do WalkForward() for 2 steps
+            do StopWalking() for 2 steps
+
+        ego = new Car at (30, 2)
+        pedestrian = new Pedestrian at (50, 6), with behavior WalkThenStop
+
+        record pedestrian.position as Pos
+        terminate after 4 steps
+    """
+    scenario = compileScenic(code, mode2D=True)
+    scene = sampleScene(scenario)
+    simulation = simulator.simulate(scene)
+    series = simulation.result.records["Pos"]
+    initialPos = series[0][1]
+    finalPos = series[-1][1]
+    assert initialPos != finalPos
+
+
 @pytest.mark.slow
 @pytest.mark.graphical
 def test_static_pedestrian(getMetadriveSimulator):
@@ -305,3 +408,58 @@ def test_composed_scenario(getMetadriveSimulator):
     assert len(traj[0]) == 2, f"expected 2 objects, got {len(traj[0])}"
     assert traj[0][0] != traj[-1][0], f"ego car did not move."
     assert traj[0][1] != traj[-1][1], f"subscenario car did not move."
+
+
+def test_render_2D_saves_gif(getMetadriveSimulator, tmp_path):
+    outdir = tmp_path / "md_gifs"
+    outdir.mkdir()
+
+    simulator, openDrivePath, sumoPath = getMetadriveSimulator(
+        "Town01",
+        render=True,
+        screen_record=True,
+        screen_record_filename="render2d.gif",
+        screen_record_path=str(outdir),
+    )
+
+    code = f"""
+        param map = r'{openDrivePath}'
+        param sumo_map = r'{sumoPath}'
+
+        model scenic.simulators.metadrive.model
+
+        ego = new Car at (30, 2)
+        terminate after 2 steps
+    """
+    scenario = compileScenic(code, mode2D=True)
+    scene = sampleScene(scenario)
+    simulator.simulate(scene)
+
+    assert (outdir / "render2d.gif").exists()
+
+
+def test_follow_lane(getMetadriveSimulator):
+    # Exercise MetaDrive's getLaneFollowingControllers via FollowLaneBehavior:
+    # car should stay on a lane and actually accelerate.
+    simulator, openDrivePath, sumoPath = getMetadriveSimulator("Town01")
+    code = f"""
+        param map = r'{openDrivePath}'
+        param sumo_map = r'{sumoPath}'
+
+        model scenic.simulators.metadrive.model
+
+        ego = new Car with behavior FollowLaneBehavior(target_speed=8)
+
+        record final (ego._lane is not None) as OnLane
+        record final ego.speed as FinalSpeed
+        terminate after 8 steps
+    """
+    scenario = compileScenic(code, mode2D=True)
+    scene = sampleScene(scenario, maxIterations=1000)
+    simulation = simulator.simulate(scene)
+    assert simulation.result.records[
+        "OnLane"
+    ], "Vehicle left the lane under FollowLaneBehavior."
+    assert (
+        simulation.result.records["FinalSpeed"] > 0.2
+    ), "Vehicle did not accelerate along the lane."