Make the lidar streamer ready to work with main controller

tracking/lidar_cache.py

@@ -19,12 +19,13 @@ class LidarCache():
         self.run = True
         self.tracking_group_number = -1
         self.currentGroups = None
+        self._group_listeners = []
 
-    def start_cache(self, sender):
-        self.thread = Thread(target=self.do_scanning, args=[sender])
+    def start_cache(self):
+        self.thread = Thread(target=self.do_scanning)
         self.thread.start()
 
-    def do_scanning(self, listener):
+    def do_scanning(self):
         """Performs scans whilst cache is running, and will pass calculated groups data to the sender.
 
         Parameters
@@ -33,8 +34,6 @@ class LidarCache():
             Any object that includes the onGroupsChanged method. 
 
         """
-        # Create the 0MQ socket first. This should not be passed between threads.
-        self._mFactory = listener
 
         # Batch over scans, so we don't need to do our own batching to determine groups
         # TODO: Implement custom batching, as iter_scans can be unreliable
@@ -65,7 +64,21 @@ class LidarCache():
                 pointScan.points.append(tracker_pb.Point(
                     angle=point[1], distance=point[2], group_number=group.number))
 
-        self._mFactory.onGroupsChanged(pointScan)
+        for listener in self._group_listeners:
+            listener.onGroupsChanged(pointScan)
+
+    def add_groups_changed_listener(self, listener):
+        """
+        Add a listener for a change in scans. THis will provide a tuple with the new group
+        scans, which can then be sent off to a network listener for display, or to update the 
+        vehicle with a new velocity.
+
+        Parameters
+        ----------
+        listener
+            An object that implements the onGroupsChanged(message) method. 
+        """
+        self._group_listeners.append(listener)
 
     def stop_scanning(self):
         self.run = False