Issue with MotionPath/MotionEvent

Troubleshooting General Help
1

Hi everybody,

I think I found an issue with MotionPath / MotionEvent classes.

It’s happening the following error:

com.jme3.app.Application handleError
SEVERE: Uncaught exception thrown in Thread[LWJGL Renderer Thread,5,main]
java.lang.IndexOutOfBoundsException: Index: 4, Size: 4
at java.util.ArrayList.rangeCheck(ArrayList.java:604)
at java.util.ArrayList.get(ArrayList.java:382)
at com.jme3.math.Spline.interpolate(Spline.java:288)
at com.jme3.cinematic.MotionPath.interpolatePath(MotionPath.java:94)
at com.jme3.cinematic.events.MotionEvent.onUpdate(MotionEvent.java:199)
at com.jme3.cinematic.events.MotionEvent.internalUpdate(MotionEvent.java:181)
at com.jme3.cinematic.events.MotionEvent.update(MotionEvent.java:164)
at com.jme3.scene.Spatial.runControlUpdate(Spatial.java:570)
at com.jme3.scene.Spatial.updateLogicalState(Spatial.java:688)
at com.jme3.scene.Node.updateLogicalState(Node.java:145)
at com.jme3.scene.Node.updateLogicalState(Node.java:152)
at com.jme3.app.SimpleApplication.update(SimpleApplication.java:244)
at com.jme3.system.lwjgl.LwjglAbstractDisplay.runLoop(LwjglAbstractDisplay.java:151)
at com.jme3.system.lwjgl.LwjglDisplay.runLoop(LwjglDisplay.java:185)
at com.jme3.system.lwjgl.LwjglAbstractDisplay.run(LwjglAbstractDisplay.java:228)
at java.lang.Thread.run(Thread.java:722)

Here is what I’m doing:

[java]
final MotionPath path = new MotionPath();
path.addWayPoint(target.getNode().getLocalTranslation());
path.addWayPoint(new Vector3f(3, -2, 7));
path.setPathSplineType(Spline.SplineType.CatmullRom);

        MotionEvent motionControl = new MotionEvent(target.getNode(),path);
        motionControl.setDirectionType(MotionEvent.Direction.PathAndRotation);
        motionControl.setSpeed(12f);
        motionControl.play();

        path.addListener(new MotionPathListener() {
            public void onWayPointReach(MotionEvent control, int wayPointIndex) {
                if (path.getNbWayPoints() == wayPointIndex + 1) {
                   System.out.println("finish");
                }
            }
        });

[/java]

I have several targets in my scene. This error is intermitent. If we had more object/target in scene moving around, the problem occurs more frequently.

This problem is occurring in Jmonkey layer. I can’t protect or treat this error in game layer. It’s outside of my code.

Did someone see this problem? Could anyone help me?

Regards,

Tati

2

Works for me, doing it with 2000 targets the same time.
[java]
@Override
public void simpleInitApp()
{
flyCam.setMoveSpeed(80);
doit(2000);
}

private void doit(int i2)
{
    for (int i = 0; i < i2; i++)
    {
        final MotionPath path = new MotionPath();
        Geometry target;
        target = new Geometry("b", new Box(2, 3, 4));
        target.setMaterial(new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md"));
        rootNode.attachChild(target);
        path.addWayPoint(target.getLocalTranslation());
        path.addWayPoint(new Vector3f((float) (Math.random() * 10), (float) (Math.random() * 12), (float) (Math.random() * 14)));
        path.setPathSplineType(Spline.SplineType.CatmullRom);

        MotionEvent motionControl = new MotionEvent(target, path);
        motionControl.setDirectionType(MotionEvent.Direction.PathAndRotation);
        motionControl.setSpeed(1f);
        motionControl.play();

        path.addListener(new MotionPathListener()
        {
            public void onWayPointReach(MotionEvent control, int wayPointIndex)
            {
                if (path.getNbWayPoints() == wayPointIndex + 1)
                {
                    System.out.println("finish");
                }
            }
        });
    }
}[/java]

What version do you use?

3

I got that once as well. I appears to happen if the 2 waypoints are the same location I think.

1 Like
4

Thanks netsky08 =D. We have some situations that we have 2 waypoints to the same locations. I will try to fix that in the code.

I will post here if it has solved the problem.

5

netsky08 you are right. It solved the problem. We spent 3 minutes to solved the problem with your tip. Thanks a lot. :slight_smile:

But Jmonkey should be prepared to treat this problem. It’s not friendly/elegant break the application. At least should use a try/catch to treat this exception.

Thanks people for your support.

6
7

gonna look into it.

8

Fixed in last revision

3 Likes
9

cool thanks! I can’t test it right now, but I guess there is nothing to worry about.

Just remember to close the issue ticket ;p

10

Awww man!!.. I had the same exception thrown and was pulling my hair out for hours until I found this thread! I was beginning to think I was crazy or something haha :stuck_out_tongue:

Thx for fixing it. Now it doesn’t crash at all anymore, it’s so relieving :smiley:

+1’ed the hero.

EDIT: Quick note, it still happens if you add two identical wayPoints (e.g.: when dynamically animating stuff on the scene, it may still happen that they are the same and throw that same out of bounds exception)

So here’s what I do now to make absolutely sure it never crashes (of course, it would be better to AVOID that entire animation if you can like using a IF branch or something):

[java]
MotionPath mypath = new MotionPath();
mypath.addWayPoint(item1.get_position().add(0, (item2.get_position().equals(item1.get_position()) ? 0.001f : 0), 0)); // Avoid IndexOutOfBoundsException
mypath.addWayPoint(item2.get_position());
[/java]