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Version: 22 May 2023

OpenXR instructions for Magic Leap 2

Using OpenXR on the Magic Leap 2 is similar to using OpenXR on any other Android device. Since not all Magic Leap 2 features are supported as extensions in OpenXR, you can mix functionality from the Magic Leap C-API with OpenXR functionality. For example, you can use ml_audio.h in OpenXR applications. Just make sure you install the MLSDK when doing so.

OpenXR sample source code is available in the Magic Leap Hub.

info

The Magic Leap 2 has been certified as conformant as of the 1.1.0 release.

Prerequisites​

Limitations​

  • One XrCompositionLayerProjection is supported.
  • A maximum of 16 composition layers at one time.
  • Each layer imposes a performance penalty, if you are seeing performance issues consider refraining from using more than one layer.
  • Currently running the OpenXR samples using the Magic Leap Application Simulator is not supported.
  • On Windows, long filenames can cause trouble while building the OpenXR samples. Please install the samples in a directory as short as possible. Alternatively, enable long file name support in Windows.

Currently Supported Extensions​

As of this writing the following extensions are supported. As always, the runtime will provide the latest list of supported extensions.

  • XR_EXT_view_configuration_depth_range
  • XR_KHR_android_create_instance
  • XR_KHR_composition_layer_depth
  • XR_KHR_opengl_es_enable
  • XR_KHR_vulkan_enable
  • XR_EXT_hand_tracking
  • XR_EXT_eye_gaze_interaction
  • XR_MND_headless
  • XR_ML_global_dimmer
  • XR_ML_frame_end_info
  • XR_KHR_convert_timespec_time
  • XR_KHR_vulkan_enable2
  • XR_MSFT_unbounded_reference_space
  • XR_ML_compat
  • XR_ML_ml2_controller_interaction

Using the Runtime​

We recommend you use the standard OpenXR loader.

If you cannot use the standard loader, the runtime binary name can be found using the Android Content Provider mechanism described in the OpenXR loader specification. Do not hardcode the path as the name might change.

Android Manifest Details​

A few entries must be added to the standard Android Manifest file to make OpenXR work on the Magic Leap 2.

Permissions​

When using hand tracking make sure to add:

com.magicleap.permission.HAND_TRACKING

<uses-permission android:name="com.magicleap.permission.HAND_TRACKING" />

When using the eye gaze extension add:

com.magicleap.permission.EYE_TRACKING

<uses-permission android:name="com.magicleap.permission.EYE_TRACKING" />
note

Please note that EYE_TRACKING is a dangerous/runtime permission, meaning that it must also be requested at runtime.

Switching to AR mode​

As with regular C-API based applications we need to tell the OS that the application is an AR application. This is done using the OpenXR standard HMD category tag.

<category android:name="org.khronos.openxr.intent.category.IMMERSIVE_HMD" />

Android Manifest Example​

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
 android:versionCode="1" android:versionName="1.0">
  <application
   android:allowBackup="false"
   android:fullBackupContent="false"
   android:icon="@mipmap/ic_launcher"
   android:label="@string/app_name"
   android:hasCode="false">

 <!-- Our activity is the built-in NativeActivity framework class.
        This will take care of integrating with our NDK code. -->
 <activity android:name="android.app.NativeActivity"
           android:label="@string/app_name"
           android:configChanges="orientation|keyboardHidden"
           android:launchMode="singleTask">

   <!-- Tell NativeActivity the name of our .so -->
   <meta-data android:name="android.app.lib_name"
              android:value="hand_tracking" />
   <intent-filter>
     <action android:name="android.intent.action.MAIN" />
     <category android:name="android.intent.category.DEFAULT" />
     <category android:name="android.intent.category.LAUNCHER" />
     <category android:name="org.khronos.openxr.intent.category.IMMERSIVE_HMD" />
   </intent-filter>
 </activity>
  </application>

  <uses-permission android:name="com.magicleap.permission.HAND_TRACKING" />
  <uses-permission android:name="org.khronos.openxr.permission.OPENXR_SYSTEM" />
  <uses-feature android:name="com.magicleap.api_level" android:version="20" />
</manifest>

Magic Leap 2 Interaction Profile​

The Magic Leap 2 Controller interaction profile is available here.

Running hello_xr​

The OpenXR working group releases a sample program called hello_xr together with their SDK package. Open this in Android Studio, attach your Magic Leap 2 device and hit “Run”.

tip

Make sure to use OpenXR 1.0.27 or higher.

Download OpenXR Samples​

To access the Package manager in ML Hub

  1. Inside the ML Hub select Package Manager.
The ML Hub with the Package Manger option selected.
  1. In the Bundles section select Native , then select Open XR in the additional packages section.
The Package Manager with the OpenXR Samples option selected.
You can also download the OpenXR Samples separately
  1. Inside the Package Manager select All.
The the Package Manger with the **All** tab selected.
  1. Then find and select the download icon for the OpenXR Samples . Located under the Common Packages section.
The Package Manager with the OpenXR Samples option selected.

Building the Magic Leap OpenXR samples​

To build the Magic Leap OpenXR samples please follow the normal Magic Leap Native SDK instructions..

These samples can be built using Android Studio or command line via Gradle.