Migrating from ML1

Upgrade to Magic Leap's new Eye Tracking APIs

The Magic Leap 2's eye tracking input can largely be accessed using Unity's Input System. However, some platform specific values are accessed via the TrackingState, which can be retrieved using Magic Leaps InputSubsystem.Extensions.

note

If your Application collects, stores, transfers or otherwise uses data off the Magic Leap 2 device that is received via this API, then you must comply with the Magic Leap 2 Eye Tracking Data Transparency Policy.

When upgrading an ML1 app please note:

• The MLEyesStarterKit class has been removed
• Use the Unity Input System to obtain generic eye trying input data such fixation point and eye rotation.
• Use InputSubsystem.Extensions.TryGetEyeTrackingState to obtain the eye tracking state and access device specific input values such as fixation confidence and blink state.

These changes to the API were made to better support and align with existing Unity frameworks like AR Foundation, XR Interaction Toolkit and the new Input System.

API Transition Table

Topic	Magic Leap 1	Magic Leap 2
Fixation point	MLEyes.FixationPoint	eyesActions.Data.ReadValue<UnityEngine.InputSystem.XR.Eyes>().fixationPoint
Left / Right eye center	MLEyes.LeftEye.Center MLEyes.LeftEye.Gaze	eyesActions.Data.ReadValue<UnityEngine.InputSystem.XR.Eyes>().leftEyePosition eyesActions.Data.ReadValue<UnityEngine.InputSystem.XR.Eyes>().leftEyeRotation
Fixation confidence	MLEyes.FixationConfidence	MLEyes.TryGetState(eyesDevice, out MLEyes.State trackingState); trackingState.FixationConfidence;
Left / Right eye confidence	MLEyes.LeftEye.CenterConfidence	MLEyes.TryGetState(eyesDevice, out MLEyes.State trackingState); trackingState.LeftCenterConfidence;
Left / Right blink state	MLEyes.LeftEye.IsBlinking	MLEyes.TryGetState(eyesDevice, out MLEyes.State trackingState); trackingState.LeftCenterConfidence;
Calibration status	Currently Not Available	MLEyes.TryGetState(eyesDevice, out MLEyes.State trackingState); trackingState.LeftBlink;
Timestamp	MLEyes.Timestamp	MLEyes.TryGetState(eyesDevice, out MLEyes.State trackingState); trackingState.Timestamp
Left / Right pupil size	MLEyes.LeftEye.PupilSize	This API is not currently Available on Magic Leap 2.

Example

Reference the example script below to see how the eye tracking APIs have changed.

Diff

The differences between the Magic Leap 1 and Magic Leap 2 script.

 using UnityEngine;
 using UnityEngine.XR.MagicLeap;
+ using UnityEngine.XR;
+ using Eyes = UnityEngine.InputSystem.XR.Eyes;

public class ExampleEyeScript : MonoBehaviour
{
+    private MagicLeapInputs mlInputs;
+    private MagicLeapInputs.EyesActions eyesActions;
+    private InputDevice eyesDevice;

+    void Start()
+    {
+        //Initialize Magic Leap Eye Tracking
+        InputSubsystem.Extensions.MLEyes.StartTracking();
+        //Initialize Magic Leap inputs to capture input data
+        mlInputs = new MagicLeapInputs();
+        mlInputs.Enable();
+        eyesActions = new MagicLeapInputs.EyesActions(mlInputs);
+    }

    // Update is called once per frame
    void Update()
    {
+        if (!eyesDevice.isValid)
+        {
+            this.eyesDevice = InputSubsystem.Utils.FindMagicLeapDevice(
+                              InputDeviceCharacteristics.EyeTracking | InputDeviceCharacteristics.TrackedDevice);
+            return;
+        }
        
+        InputSubsystem.Extensions.TryGetEyeTrackingState(eyesDevice, out var trackingState);
+        Eyes eyes = eyesActions.Data.ReadValue<UnityEngine.InputSystem.XR.Eyes>(); 

+        if (trackingState.FixationConfidence > 0.5f)
-        if (MLEyes.IsStarted && MLEyes.CalibrationStatus == MLEyes.Calibration.Good)
        {
            Vector3 worldPosition = Camera.main.transform.position;
+           Vector3 worldRotation = (eyes.fixationPoint - worldPosition).normalized;
-           Vector3 worldRotation = (MLEyes.FixationPoint - worldPosition).normalized;
            // Will only be visible in editor when using App Simulator
            Debug.DrawRay(worldPosition, worldRotation);

+            Debug.Log("Left Eye Is Blinking: " + trackingState.LeftBlink);
-            Debug.Log("Left Eye Is Blinking: " + MLEyes.LeftEye.IsBlinking);
+            Debug.Log("Left Eye Center: " + eyes.leftEyePosition);
-            Debug.Log("Left Eye Center: " + MLEyes.LeftEye.Center);
+            Debug.Log("Left Eye Rotation: " + eyes.leftEyeRotation);
-            Debug.Log("Left Eye Rotation: " + MLEyes.LeftEye.Gaze);
        }
    }
+    private void OnDestroy()
+    {
+        mlInputs.Disable();
+        mlInputs.Dispose();
+    }
}

Magic Leap 1

This is the Magic leap 1 script

using UnityEngine;
using UnityEngine.XR.MagicLeap;

public class ExampleEyeScript: MonoBehaviour
{
    // Update is called once per frame
    void Update()
    {
        if (MLEyes.IsStarted
            && MLEyes.CalibrationStatus == MLEyes.Calibration.Good)
        {
            Vector3 worldPosition = Camera.main.transform.position;
            Vector3 worldRotation = (MLEyes.FixationPoint - worldPosition).normalized;

            // Will only be visible in editor when using App Simulator
            Debug.DrawRay(worldPosition, worldRotation);

            Debug.Log("Left Eye Is Blinking: " + MLEyes.LeftEye.IsBlinking);
            Debug.Log("Left Eye Center: " + MLEyes.LeftEye.Center);
            Debug.Log("Left Eye Rotation: " + MLEyes.LeftEye.Gaze);
        }
    }
}

Magic Leap 2

This is the complete Magic Leap 2 Script

using UnityEngine;
using UnityEngine.XR.MagicLeap;
using UnityEngine.XR;
using Eyes = UnityEngine.InputSystem.XR.Eyes;

public class ExampleEyeScript: MonoBehaviour
{
    private MagicLeapInputs mlInputs;
    private MagicLeapInputs.EyesActions eyesActions;
    private InputDevice eyesDevice;

    // Start is called before the first frame update
    void Start()
    {
        //Initialize Magic Leap Eye Tracking
        InputSubsystem.Extensions.MLEyes.StartTracking();
        //Initialize Magic Leap inputs to capture input data
        mlInputs = new MagicLeapInputs();
        mlInputs.Enable();
        eyesActions = new MagicLeapInputs.EyesActions(mlInputs);
    }

    // Update is called once per frame
    void Update()
    {
        if (!eyesDevice.isValid)
        {
            this.eyesDevice = InputSubsystem.Utils.FindMagicLeapDevice(
            InputDeviceCharacteristics.EyeTracking | InputDeviceCharacteristics.TrackedDevice);
            return;
        }
        
        InputSubsystem.Extensions.TryGetEyeTrackingState(eyesDevice, out var trackingState);
        Eyes eyes = eyesActions.Data.ReadValue<UnityEngine.InputSystem.XR.Eyes>(); 

        if (trackingState.FixationConfidence > 0.5f)
        {
            Vector3 worldPosition = Camera.main.transform.position;
            Vector3 worldRotation = (eyes.fixationPoint - worldPosition).normalized;

            // Will only be visible in editor when using App Simulator
            Debug.DrawRay(worldPosition, worldRotation);

            Debug.Log("Left Eye Is Blinking: " + trackingState.LeftBlink);
            Debug.Log("Left Eye Center: " + eyes.leftEyePosition);
            Debug.Log("Left Eye Rotation: " + eyes.leftEyeRotation);
        }
    }
    private void OnDestroy()
    {
        mlInputs.Disable();
        mlInputs.Dispose();
    }
}