Replaced camera tracking listeners with animation timer

- Documented animation timers and mark arrow

#story[1195]

racevisionGame/src/main/java/visualiser/Controllers/RaceController.java

@@ -81,7 +81,13 @@ public class RaceController extends Controller {
     private View3D view3D;
     private ObservableList<Subject3D> viewSubjects;
 
+    /**
+     * Arrow pointing to next mark in third person
+     */
     private Subject3D nextMarkArrow;
+    /**
+     * Animation loop for rotating mark arrow
+     */
     private AnimationTimer pointToMark;
 
     /**

racevisionGame/src/main/java/visualiser/layout/View3D.java

@@ -1,5 +1,6 @@
 package visualiser.layout;
 
+import javafx.animation.AnimationTimer;
 import javafx.beans.property.ObjectProperty;
 import javafx.beans.property.SimpleObjectProperty;
 import javafx.beans.value.ChangeListener;
@@ -71,21 +72,9 @@ public class View3D extends Pane {
      */
     private Rotate pitch;
     /**
-     * Single listener for subject heading changes
+     * Animation loop for camera tracking
      */
-    private ChangeListener<? super Number> pivotHeading = (o, prev, curr) -> yaw.setAngle((double)curr);
+    private AnimationTimer trackBoat;
-    /**
-     * Single listener for subject position (x) changes
-     */
-    private ChangeListener<? super Number> pivotX = (o, prev, curr) -> pivot.setX((double)curr);
-    /**
-     * Single listener for subject position (y) changes
-     */
-    private ChangeListener<? super Number> pivotY = (o, prev, curr) -> pivot.setY((double)curr);
-    /**
-     * Single listener for subject position (z) changes
-     */
-    private ChangeListener<? super Number> pivotZ = (o, prev, curr) -> pivot.setZ((double)curr);
     /**
      * Distance to switch from third person to bird's eye
      */
@@ -219,10 +208,7 @@ public class View3D extends Pane {
      */
     private void untrackSubject() {
         if(target.get() != null) {
-            target.get().getPosition().xProperty().removeListener(pivotX);
+            trackBoat.stop();
-            target.get().getPosition().yProperty().removeListener(pivotY);
-            target.get().getPosition().zProperty().removeListener(pivotZ);
-            target.get().getHeading().angleProperty().removeListener(pivotHeading);
             target.setValue(null);
         }
     }
@@ -234,13 +220,14 @@ public class View3D extends Pane {
     private void trackSubject(Subject3D subject) {
         target.set(subject);
 
+        this.trackBoat = new AnimationTimer() {
+            @Override
+            public void handle(long now) {
                 updatePivot(target.get().getPosition());
                 setYaw(target.get().getHeading().getAngle());
-
+            }
-        target.get().getPosition().xProperty().addListener(pivotX);
+        };
-        target.get().getPosition().yProperty().addListener(pivotY);
+        trackBoat.start();
-        target.get().getPosition().zProperty().addListener(pivotZ);
-        target.get().getHeading().angleProperty().addListener(pivotHeading);
     }
 
     public void setNearClip(double nearClip) {