Exercise - Use eye tracking

Completed

In this exercise, you'll learn how to enable eye tracking for HoloLens 2 and add eye tracking to objects to trigger actions when the user looks at the objects.

Ensure the eye gaze input capability is enabled

• In the Unity menu, select Edit > Project Settings. Expand XR Plugin-in Management, then select OpenXR and make sure that the Eye Gaze Interaction Profile has been added to the Interaction Profiles.

  

Enable simulated eye tracking for the Unity editor

• From the previous module, you should already have the MRTK XR Rig in your scene. Gaze input is included in this prefab, so you don’t need to add any extra components.

  

Add eye tracking to objects

1. In the Hierarchy window, expand RoverExplorer > Buttons > Hints. Right-click the Hints game object, and then select 3D Object > Text - TextMeshPro. Rename the newly created game object to ButtonText.

   

2. In the Hierarchy window, select RoverExplorer > Buttons > Hints > ButtonText. Change its Text Input to Hints, Font Size to 2, Pos X to 9.75, Pos Y to -1.50 and Pos Z to -0.3.

   

3. In the Hierarchy window, expand RoverExplorer > Buttons > Hints > ButtonText. Then, in the Hierarchy window, select the Hints button object and configure the PressableButton component as follows:

   • Under XRI Interactable Events, in the Hover Entered section:

     1. Select the small + icon to add another event.
     2. Assign the ButtonText object from the Hints button to the None (Object) field.
     3. From the No Function dropdown, select TextMeshPro > float fontSize to update this property value when the event is triggered.
     4. Set the argument to 3 to increase the current font size to 3.

   • In the Hover Exited section:

     1. Select the small + icon to add another event.
     2. Assign the ButtonText object from the Hints button to the None (Object) field.
     3. From the No Function dropdown, select TextMeshPro > float fontSize to update this property value when the event is triggered.
     4. Set the argument to 2 to reset the font size back 2.

   

4. Repeat the preceding steps for the Explode and Reset button objects to configure eye tracking for remaining buttons. If you now enter Game mode and press and hold the right mouse button while moving your mouse until the gaze hits one of the buttons, you'll see the text font size increase, then reset back to its original size when you look away.