Passthrough Toggle Tutorial

• Load and explore the EnableDisablePassthrough scene.
• Use the PassthroughLayerResumed event.
• Modify and update the scene.

• Set Up Unity for XR development to create a project with the necessary dependencies
• Set up your device to configure and test your project on a headset

1. Navigate to the Unity starter samples⁠ GitHub repository.
2. Click the Code button aligned on the right side of the file list and then select Download ZIP to download the samples. Alternatively, you can follow instructions in the Getting the Code⁠ section to clone the repository.
   
3. After you’ve downloaded the samples, extract the files into a new folder.
4. Open Unity Hub and navigate to the Projects page located on the left. Select the Add dropdown at the top right and click Add project from disk.
   
5. Navigate to the folder you previously extracted and click the Open option. This will create a new project in Unity Hub for you to work in.
6. In the Editor Version dropdown, select version 2022.3.15f1 or newer. If necessary, you can follow these steps to install the latest version of the Unity Editor.
7. Open your new project. It may take a while to open the project for the first time.
8. Restart your editor to propagate the changes if prompted.
9. In the Project Validation window that opens automatically, click the Fix All option. This will resolve any issues that may occur when updating the project to the latest version of Unity.
   

1. In the Project window, select Assets > StarterSamples > Usage > Passthrough > Scenes > EnableDisablePassthrough to load the scene.
2. Connect your headset to your PC with Link and then click the Play button at the top of the Unity screen to start the scene on your headset.
3. From your headset, look around the default scene, which consists of a text box containing instructions and a button labeled Subscribe to the PassthroughLayerResumed event, a standard plane beneath you, and a skybox. Move your controllers around and press their buttons. Try each of the controller actions in your scene:
   • The A button toggles the passthrough feature on or off.
   • Point the controller at the button on the text box and press the trigger to enable and disable the PassthroughLayerResumed event.
   • The left controller option button allows you to change the active starter scene.
4. Toggle the button on and off to test passthrough with the event both active and inactive, and observe the differences. The button label will indicate the current state of the event. Unsubscribe to the PassthroughLayerResumed event indicates that the event is active, while Subscribe to the PassthroughLayerResumed event indicates that the event is not active.
   

• Static - An object that contains components that are expected to stay the same during runtime. This contains the Light and Ground objects.
• OVRCameraRig - The root of the Meta XR camera rig hierarchy. Contains the eye and hand anchor components which work in tandem to automatically send head and positional tracking data to Unity, allowing the camera to precisely mirror the user’s movements and orientation in real life. It contains the following critical components that enable passthrough and the PassthroughLayerResumed event:
  • Passthrough Renderer - Manages rendering of the passthrough video feed, compositing, depth, and alignment with virtual content.
  • OVR Passthrough Layer Script - The main interface for enabling, configuring, and controlling passthrough video in a scene on Meta Quest devices.
• UIHelpers - This object includes the UI components responsible for managing the ray projected from the controller, as well as the event system that enables user interaction with the button.
• ReturnToStartScene - This object contains the script that handles the functionality of the left controller menu button, represented by three horizontal lines, allowing the user to switch between the starter scenes.
• Controller - This object contains the Enable Disable Passthrough Controller Script. This script enables the user to toggle the PassthroughLayerResumed event on and off during runtime.
• Description - This object contains all of the components required to render the text box and its contents.

1. In the Hierarchy on the left, expand the Description object and then click the CallbackToggle object.
2. In the Inspector tab, locate the Toggle component. Check the box for the Is On option.
   
3. In the Hierarchy on the left, expand the Description object and then click the InfoPanel object.
4. Locate the Canvas component and disable it via the checkbox in the top left corner of the component.
   
5. Next, add a sphere to your scene that remains visible whether passthrough is enabled or disabled. This sphere serves as an example of an object or platform that persists in both the virtual and physical worlds, making it easier to observe the improved passthrough transition provided by the PassthroughLayerResumed event. Right click in the Unity Hierarchy and select 3D Object > Sphere.
6. Select the new Sphere object in the Hierarchy. Locate the Transform component in the Inspector. Update the Position coordinates to (0,1,2) to ensure it is positioned in front of the camera when starting the scene.
   
7. Click Add Component. Add the OVR Passthrough Layer (Script) component to the sphere. This script ensures the sphere remains when passthrough is activated.
   
8. In the Hierarchy, delete the Ground object nested under Static. This gives users 360-degree passthrough when running the scene.
   

• OVRCameraRig: Learn how to configure the Meta XR camera.
• Starter Samples: See all the starter sample tutorials.