simple – SYAZMEDIA PLT

Edit 2021 Update:

Notice, this codes are no longer needed as Vuforia has provided their own Unity Events Handler. So If you are using the latest Vuforia, it comes built in. It looks like the picture below and it works exactly the same as the one I wrote here.

This post below is still kept as there are people still struggling to update their old projects, so this is for you guys/gals in University, hope you can update soon!

Do you ever wish that Vuforia event handling is as simple as using the OnClick() property in Unity UI’s Button? Wish no more bros and sis. Here the code, and explanation on how I did it.

Click Here To Download EasyEventHandler Unity Package

The Code

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;
using Vuforia;

    public class EasyEventHandler : MonoBehaviour, ITrackableEventHandler
    {

    public UnityEvent onMarkerFound;
    public UnityEvent onMarkerLost;

        protected TrackableBehaviour mTrackableBehaviour;
        protected TrackableBehaviour.Status m_PreviousStatus;
        protected TrackableBehaviour.Status m_NewStatus;



        protected virtual void Start()
        {
            mTrackableBehaviour = GetComponent<TrackableBehaviour>();
            if (mTrackableBehaviour)
                mTrackableBehaviour.RegisterTrackableEventHandler(this);
        }

        protected virtual void OnDestroy()
        {
            if (mTrackableBehaviour)
                mTrackableBehaviour.UnregisterTrackableEventHandler(this);
        }


        public void OnTrackableStateChanged(
            TrackableBehaviour.Status previousStatus,
            TrackableBehaviour.Status newStatus)
        {
            m_PreviousStatus = previousStatus;
            m_NewStatus = newStatus;

            if (newStatus == TrackableBehaviour.Status.DETECTED ||
                newStatus == TrackableBehaviour.Status.TRACKED ||
                newStatus == TrackableBehaviour.Status.EXTENDED_TRACKED)
            {
                onMarkerFound.Invoke();
            }
            else if (previousStatus == TrackableBehaviour.Status.TRACKED &&
                     newStatus == TrackableBehaviour.Status.NO_POSE)
            {
 
                onMarkerLost.Invoke();
            }
            else
            {
            // For combo of previousStatus=UNKNOWN + newStatus=UNKNOWN|NOT_FOUND
            // Vuforia is starting, but tracking has not been lost or found yet
            // Call OnTrackingLost() to hide the augmentations
            onMarkerLost.Invoke();
            }
        }
    }

How it looks like

Explanation

Creating the Unity Events and Exposing it in Inspector

This code uses the UnityEngine.Events . Firstly, I create two UnityEvents variable, and make the variables public, doing this I get to expose the events, giving you that familiar On Click () thingy in Unity UI Button.

    public UnityEvent onMarkerFound;
    public UnityEvent onMarkerLost;

Invoking the Events when marker is detected and lost

Then, OnTrackableStateChanged, if the Image Target is detected, I use the UnityEvent’s Invoke() function to Invoke the event, this will then work just like the On Click ()

Tag: simple

Simpler Vuforia Event Handling using Unity Events