adding basic scene with marker detection

AR/Assets/MarkerTracker.cs

@@ -0,0 +1,69 @@
+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.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;
+            // }
+            // }
+            // }
+            _instantiatedPrefabs[trackedImage.referenceImage.name].SetActive(trackedImage.trackingState == TrackingState.Tracking);
+        }
+
+
+        foreach (var trackedImage in eventArgs.removed) {
+            // Destroy its prefab
+            Destroy(_instantiatedPrefabs[trackedImage.referenceImage.name]);
+            // Also remove the instance from our array
+            _instantiatedPrefabs.Remove(trackedImage.referenceImage.name);
+            // Or, simply set the prefab instance to inactive
+            //_instantiatedPrefabs[trackedImage.referenceImage.name].SetActive(false);
+        }
+    }
+}