Occlusion

This page supplements the AR Foundation Occlusion manual. The following sections only contain information about APIs where Google's Android XR runtime exhibits platform-specific behavior.

Tip

When developing an AR app, refer to both the AR Foundation documentation as well as the required packages for each platform you support.

Optional feature support

Android XR implements the following optional features of AR Foundation's XROcclusionSubsystem:

Feature	Descriptor Property	Supported
Environment Depth Image	environmentDepthImageSupported	Yes
Environment Depth Confidence Image	environmentDepthConfidenceImageSupported	Yes
Environment Depth Temporal Smoothing	environmentDepthTemporalSmoothingSupported	Yes
Human Segmentation Stencil Image	humanSegmentationStencilImageSupported
Human Segmentation Depth Image	humanSegmentationDepthImageSupported

Occlusion samples

AR Foundation provides the HMDOcclusion sample to demonstrate occlusion on head-mounted displays (HMDs). For more information about HMD occlusion, refer to AR Shader Occlusion component (AR Foundation).

To test occlusion on Android XR with the occlusion sample:

1. Clone the AR Foundation Samples repo from the AR Foundations Samples GitHub repository and open it in Unity.
2. Open the HMDOcclusion scene in Unity from Assets/Scenes/Occlusion/HMDOcclusion.
3. Create a new material and set its shader to Assets/Shaders/Occlusion/OcclusionSimpleLit/OcclusionSimpleLit.shader. Refer to Creating Materials for more information about creating and applying materials.
4. Apply the new material to a sample cube in the scene and position as desired.
5. Open the AROcclusionManager in the Inspector window, and disable Temporal Smoothing.

Permissions

AR Foundation's occlusion detection feature requires an Android system permission on the Android XR runtime. Your user must grant your app the android.permission.SCENE_UNDERSTANDING_FINE permission before it can track occlusion data.

To avoid permission-related errors at runtime, set up your scene with the AR Occlusion Manager component disabled, then enable it only after the required permission is granted.

The following example code demonstrates how to handle required permissions and enable the AR Occlusion Manager component:

        const string k_Permission = "android.permission.SCENE_UNDERSTANDING_FINE";

        [SerializeField]
        AROcclusionManager m_AROcclusionManager;

#if UNITY_ANDROID
        void Start()
        {
            if (!Permission.HasUserAuthorizedPermission(k_Permission))
            {
                var callbacks = new PermissionCallbacks();
                callbacks.PermissionDenied += OnPermissionDenied;
                callbacks.PermissionGranted += OnPermissionGranted;

                Permission.RequestUserPermission(k_Permission, callbacks);
            }
            else
            {
                // enable the AR Occlusion Manager component if permission is already granted
                m_AROcclusionManager.enabled = true;
            }
        }

        void OnPermissionDenied(string permission)
        {
            // handle denied permission
        }

        void OnPermissionGranted(string permission)
        {
            // enable the AR Occlusion Manager component if permission is already granted
            m_AROcclusionManager.enabled = true;
            m_AROcclusionManager.subsystem.Stop();
            m_AROcclusionManager.subsystem.Start();
        }
#endif // UNITY_ANDROID

For a code sample that involves multiple permissions in a single request, refer to the Permissions page.