How to register for event in Unity3D ARToolKit 6 for OnMarkerFound?

Question

I am following this tutorial here

https://github.com/artoolkit/ar6unity-wiki/wiki/Setting-Up-Your-First-ARToolKit-for-Unity-Scene

I need to register for event from the Marker so that it triggers OnMarkerFound. The below post is out of date

OnMarkerFound event not getting called - Unity3D ARToolKit

https://archive.artoolkit.org/documentation/doku.php?id=6_Unity:unity_scripts

I read AAREventReceiver.cs file and it said things very vague:

using UnityEngine;

/// <summary>
/// Any object that implements IAREventReceiver is eligable to register for tracking
/// events from any ARTrackable object.
/// To register with an ARTrackable:
///   arTrackedMarker.eventReceivers.add(this);
/// </summary>
/// 
public abstract class AAREventReceiver : MonoBehaviour {
    public abstract void OnMarkerFound(ARTrackable marker);
    public abstract void OnMarkerTracked(ARTrackable marker);
    public abstract void OnMarkerLost(ARTrackable marker);
}

For example, I cannot find IAREventReceiver anywhere. Also where do I put arTrackedMarker.eventReceivers.add(this);?

Then I looked in my AR Trackable object to register the event receivers. The asset list showing none although I have many GameObjects available to register the event.

Frankly, I don't know how to register the event in v6 here. Even this doc is not accurate

https://archive.artoolkit.org/documentation/doku.php?id=6_Unity:unity_scripts

Can you please point me out? Thanks.

Answer 1

the documentation inside AAREventReceiver.cs is wrong. It should say:

"Any object that implements AAREventReceiver is eligible (...)"

Having said that. You need to write your own script that contains these function implementations:

public abstract void OnMarkerFound(ARTrackable marker);
public abstract void OnMarkerTracked(ARTrackable marker);
public abstract void OnMarkerLost(ARTrackable marker);

And make it extend AAREventReceiver:

public class MyEventReceiver : AAREventReceiver {
    public abstract void OnMarkerFound(ARTrackable marker){
        //log OnMarkerFound
    }
    public abstract void OnMarkerTracked(ARTrackable marker){
        //log OnMarkerTracked
    }
    public abstract void OnMarkerLost(ARTrackable marker){
        //log OnMarkerLost
    }
}

Then you can select the MyEventReceiver in the EventReceivers-List as 'Element 0' (referring to your screenshot)

I wrote an article here: http://augmentmy.world/migratetoartoolkit6 on how to migrate from ARToolKit5 to ARToolKit6

Hope that helps

===Edit 1: ===

You don't need this

arTrackedMarker.eventReceivers.add(this);

anymore with ARToolKit6