Marker Understanding Example

This section includes an example of detecting Fiducial Markers on the Magic Leap 2 headset.

Simple Example

This script detects markers and creates a cube at each of the target's location. The script does not handle runtime changes to the Marker Tracker settings.

caution

This feature requires the MARKER_TRACKING permission to be enabled in your project's Manifest Settings. (Edit > Project Settings > Magic Leap > Manifest Settings)

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.XR.OpenXR;
using UnityEngine.XR.OpenXR.Features.MagicLeapSupport;

public class MarkerTrackerExample : MonoBehaviour
{
    public MagicLeapMarkerUnderstandingFeature.ArucoType ArucoType =
        MagicLeapMarkerUnderstandingFeature.ArucoType.Dictionary_5x5_50;

    public MagicLeapMarkerUnderstandingFeature.MarkerDetectorProfile DetectorProfile =
        MagicLeapMarkerUnderstandingFeature.MarkerDetectorProfile.Default;

    private MagicLeapMarkerUnderstandingFeature.MarkerDetectorSettings detectorSettings;
    private MagicLeapMarkerUnderstandingFeature markerFeature;
    private Dictionary<string, GameObject> _markers = new Dictionary<string, GameObject>();

    private void Start()
    {
        markerFeature = OpenXRSettings.Instance.GetFeature<MagicLeapMarkerUnderstandingFeature>();

        if (markerFeature == null || markerFeature.enabled == false)
        {
            Debug.LogError("The Magic Leap 2 Marker Understanding OpenXR Feature is missing or disabled enabled. Disabling Script.");
            this.enabled = false;
            return;
        }

        //Configure a generic detector
        detectorSettings.QRSettings.EstimateQRLength = true;

        detectorSettings.ArucoSettings.EstimateArucoLength = true;

        detectorSettings.ArucoSettings.ArucoType = ArucoType;
        detectorSettings.MarkerDetectorProfile = DetectorProfile;

        //Create Aruco detector
        detectorSettings.MarkerType = MagicLeapMarkerUnderstandingFeature.MarkerType.Aruco;
        markerFeature.CreateMarkerDetector(detectorSettings);

        //Create QRCode Detector
        detectorSettings.MarkerType = MagicLeapMarkerUnderstandingFeature.MarkerType.QR;
        markerFeature.CreateMarkerDetector(detectorSettings);

        //Create UPCA Detector
        detectorSettings.MarkerType = MagicLeapMarkerUnderstandingFeature.MarkerType.UPCA;
        markerFeature.CreateMarkerDetector(detectorSettings);
    }

    private void OnDestroy()
    {
        if (markerFeature != null)
        {
            markerFeature.DestroyAllMarkerDetectors();
        }
    }

    void Update()
    {
        //Update the marker detector
        markerFeature.UpdateMarkerDetectors();

        // Iterate through all of the marker detectors
        for (int i = 0; i < markerFeature.MarkerDetectors.Count; i++)
        {
            //Verify that the marker detector is running
            if (markerFeature.MarkerDetectors[i].Status == MagicLeapMarkerUnderstandingFeature.MarkerDetectorStatus.Ready)
            {
                //Cycle through the detector's data and log it to the debug log
                MagicLeapMarkerUnderstandingFeature.MarkerDetector currentDetector = markerFeature.MarkerDetectors[i];
                OnUpdateDetector(currentDetector);
            }
        }
    }

    private void OnUpdateDetector(MagicLeapMarkerUnderstandingFeature.MarkerDetector detector)
    {

        for (int i = 0; i < detector.Data.Count; i++)
        {
            string id = "";
            float markerSize = .01f;
            var data = detector.Data[i];
            switch (detector.Settings.MarkerType)
            {
                case MagicLeapMarkerUnderstandingFeature.MarkerType.Aruco:
                    id = data.MarkerNumber.ToString();
                    markerSize = data.MarkerLength;
                    break;
                case MagicLeapMarkerUnderstandingFeature.MarkerType.QR:
                    id = data.MarkerString;
                    markerSize = data.MarkerLength;
                    break;
                case MagicLeapMarkerUnderstandingFeature.MarkerType.UPCA:
                    Debug.Log("No pose is given for marker type UPCA, value is " + id);
                    break;
            }

            if (!string.IsNullOrEmpty(id))
            {
                if (_markers.ContainsKey(id))
                {
                    GameObject marker = _markers[id];
                    marker.transform.position = data.MarkerPose.position;
                    marker.transform.rotation = data.MarkerPose.rotation;
                }
                else
                {
                    //Create a primitive cube
                    GameObject marker = GameObject.CreatePrimitive(PrimitiveType.Cube);
                    //Render the cube with the default URP shader
                    marker.AddComponent<Renderer>();
                    marker.GetComponent<Renderer>().material = new Material(Shader.Find("Universal Render Pipeline/Lit"));
                    marker.transform.position = data.MarkerPose.position;
                    marker.transform.rotation = data.MarkerPose.rotation;
                    marker.transform.localScale = new Vector3(markerSize, markerSize, markerSize);
                    _markers.Add(id, marker);
                }
            }
        }
    }
}