Added example reward functions.

reward-example-pure-pursuit.py

@@ -0,0 +1,32 @@
+  def reward_function(self, on_track, x, y, distance_from_center, car_orientation, progress, steps,
+                        throttle, steering, track_width, waypoints, closest_waypoints):
+
+        reward = 1e-3
+
+        rabbit = [0,0]
+        pointing = [0,0]
+
+        # Reward when yaw (car_orientation) is pointed to the next waypoint IN FRONT.
+
+        # Find nearest waypoint coordinates
+
+        rabbit = [waypoints[closest_waypoints+1][0],waypoints[closest_waypoints+1][1]]
+
+        radius = math.hypot(x - rabbit[0], y - rabbit[1])
+
+        pointing[0] = x + (radius * math.cos(car_orientation))
+        pointing[1] = y + (radius * math.sin(car_orientation))
+
+        vector_delta = math.hypot(pointing[0] - rabbit[0], pointing[1] - rabbit[1])
+
+        # Max distance for pointing away will be the radius * 2
+        # Min distance means we are pointing directly at the next waypoint
+        # We can setup a reward that is a ratio to this max.
+
+        if vector_delta == 0:
+            reward += 1
+        else:
+            reward += ( 1 - ( vector_delta / (radius * 2)))
+
+        return reward
+