T-DEV-811/AR/Assets/MarkerTracker.cs

using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.XR.ARFoundation;
using UnityEngine.XR.ARSubsystems;

[RequireComponent(typeof(ARTrackedImageManager))]
public class MarkerTracker : MonoBehaviour
{
    // Reference to AR tracked image manager component
    private ARTrackedImageManager _trackedImagesManager;

    // List of prefabs to instantiate - these should be named the same
    // as their corresponding 2D images in the reference image library 
    public GameObject[] ArPrefabs;


    private readonly Dictionary<string, GameObject> _instantiatedPrefabs = new Dictionary<string, GameObject>();
    //  foreach(var trackedImage in eventArgs.added){
    // Get the name of the reference image
    //   var imageName = trackedImage.referenceImage.name;
    //   foreach (var curPrefab in ArPrefabs) {
    // Check whether this prefab matches the tracked image name, and that
    // the prefab hasn't already been created
    //  if (string.Compare(curPrefab.name, imageName, StringComparison.OrdinalIgnoreCase) == 0
    //   && !_instantiatedPrefabs.ContainsKey(imageName)){
    // Instantiate the prefab, parenting it to the ARTrackedImage
    //  var newPrefab = Instantiate(curPrefab, trackedImage.transform);
     void Awake()
    {
        _trackedImagesManager = GetComponent<ARTrackedImageManager>();
    }
    private void OnEnable()
    {
        _trackedImagesManager.trackedImagesChanged += OnTrackedImagesChanged;
    }
    private void OnDisable()
    {
        _trackedImagesManager.trackedImagesChanged -= OnTrackedImagesChanged;
    }
    private void OnTrackedImagesChanged(ARTrackedImagesChangedEventArgs eventArgs)
    {

        foreach (var trackedImage in eventArgs.added)
        {
            foreach (var arPrefab in ArPrefabs)
            {
                if (arPrefab.name == trackedImage.referenceImage.name && !_instantiatedPrefabs.ContainsKey(ArPrefabs[0].name))
                {
                    var newPrefab = Instantiate(ArPrefabs[0], trackedImage.transform);
                    _instantiatedPrefabs.Add(ArPrefabs[0].name, newPrefab);
                    return;
                }
            }
        }
        
        foreach (var trackedImage in eventArgs.updated)
        {
            // var imageName = trackedImage.referenceImage.name;
            //foreach (var curPrefab in AreaEffector2DPrefabs)
            // {
            // if (string.Compare(curPrefab.name, imageName, StringComparison.OrdinalIgnoreCase) == 0
            //  && !_instantiatedPrefabs.ContainsKey(imageName))
            //  {
            //  var newPrefab = Instantiate(curPrefab, trackedImage.transform);
            //   _instantiatedPrefabs[imageName] = newPrefab;
            // }
            // }
            // }
            //Debug.Log("Updated : " + trackedImage.referenceImage.name);
            //_instantiatedPrefabs[trackedImage.referenceImage.name].SetActive(trackedImage.trackingState == TrackingState.Tracking);
            foreach (var existingPrefab in _instantiatedPrefabs)
            {
                if (existingPrefab.Key == trackedImage.referenceImage.name)
                {
                    _instantiatedPrefabs[trackedImage.referenceImage.name].SetActive(trackedImage.trackingState == TrackingState.Tracking);
                }
            }
        }


        foreach (var trackedImage in eventArgs.removed) {
            // Destroy its prefabDestroy(_instantiatedPrefabs[trackedImage.referenceImage.name]);
            
            foreach (var existingPrefab in _instantiatedPrefabs)
            {
                if (existingPrefab.Key == trackedImage.referenceImage.name)
                {
                    _instantiatedPrefabs[trackedImage.referenceImage.name].SetActive(false);
                }
            }
            
            // Also remove the instance from our array
            //Debug.Log("Deleted : " + trackedImage.referenceImage.name);
            //_instantiatedPrefabs.Remove(trackedImage.referenceImage.name);
            // Or, simply set the prefab instance to inactive
            //_instantiatedPrefabs[trackedImage.referenceImage.name].SetActive(false);
        }
    }
}