volkswagen: read MQB EVO radar tracks from Strukturen_01

opendbc_repo/opendbc/car/volkswagen/radar_interface.py

@@ -18,15 +18,29 @@ SIGNAL_SETS = tuple(
 )
 
 
+# The gateway harness does not expose the raw radar points, but the camera publishes filtered
+# tracks: two per lane, for the left, center and right lanes. MEB calls that message
+# MEB_Distance_01, while the MQB EVO DBC carries the exact same payload as Strukturen_01.
+RADAR_TRACK_MESSAGE = (
+  (VolkswagenFlags.MEB, "MEB_Distance_01"),
+  (VolkswagenFlags.MQB_EVO, "Strukturen_01"),
+)
+
+
 class RadarInterface(RadarInterfaceBase):
   def __init__(self, CP, CP_SP):
     super().__init__(CP, CP_SP)
 
-    # With the MEB gateway harness, we do not have access to the raw points from the radar.
-    # However, the camera publishes decent, albeit filtered, tracks. Two for each lane; left, center, and right.
     self.rcp: CANParser | None = None
-    if CP.flags & (VolkswagenFlags.MEB | VolkswagenFlags.MQB_EVO) and not self.CP.radarUnavailable:
-      self.rcp = CANParser(DBC[CP.carFingerprint][Bus.radar], [("MEB_Distance_01", 25)], CanBus(CP).cam)
+    self.radar_message: str | None = None
+    if not self.CP.radarUnavailable:
+      for flag, message in RADAR_TRACK_MESSAGE:
+        if CP.flags & flag:
+          self.radar_message = message
+          break
+
+    if self.radar_message is not None:
+      self.rcp = CANParser(DBC[CP.carFingerprint][Bus.radar], [(self.radar_message, 25)], CanBus(CP).cam)
 
   def update(self, can_strings):
     if self.rcp is None:
@@ -34,8 +48,10 @@ class RadarInterface(RadarInterfaceBase):
 
     self.rcp.update(can_strings)
 
-    if len(self.rcp.vl_all["MEB_Distance_01"]["Distance_Status"]) == 0:
-      return None
+    if len(self.rcp.vl_all[self.radar_message]["Distance_Status"]) == 0:
+      # The track message hasn't been seen yet. Keep publishing empty radar data instead of
+      # nothing, so consumers waiting on radarTracks don't stall.
+      return super().update(None)
 
     return self._update()
 
@@ -46,7 +62,7 @@ class RadarInterface(RadarInterfaceBase):
       ret.errors.canError = True
       return ret
 
-    msg = self.rcp.vl["MEB_Distance_01"]
+    msg = self.rcp.vl[self.radar_message]
 
     # Can be 3 when radar sensor is obstructed
     if msg["Distance_Status"] != 0: