Unity XR Input

This section provides information on all Unity-supported input devices for virtual realityA system that immerses users in an artificial 3D world of realistic images and sounds, using a headset and motion tracking. More info
See in Glossary, augmented reality and Windows Mixed RealityA mixed reality platform developed by Microsoft, built around the API of Windows 10. More info
See in Glossary applications. This page is broken up into the following sections:

• XR input mappings
• Accessing input devices
• Accessing input features on an input device
• Accessing XR input via the legacy input system
• Haptics

XR platforms typically provide a rich diversity of input features for you to take advantage of when designing user interactions. Positions, rotations, touch, buttons, joysticks, and finger sensors all provide specific pieces of data.

At the same time, access to these input features vary between different XRAn umbrella term encompassing Virtual Reality (VR), Augmented Reality (AR) and Mixed Reality (MR) applications. Devices supporting these forms of interactive applications can be referred to as XR devices. More info
See in Glossary platforms. The Vive and the Oculus RiftA VR headset for using apps made for the Oculus platform. More info
See in Glossary have subtle differences, while there are drastic differences between a desktop VR platform and a mobile platform like Daydream.

Unity provides a C# struct called InputFeatureUsage, which defines a standard set of physical device elements (such as buttons and triggers) to access user input in a platform-agnostic way. These help you quickly identify input types by name. See XR.Input.CommonUsages for a definition of each InputFeatureUsage.

Each InputFeatureUsage corresponds to a common input action or type. For example, Unity defines the InputFeatureUsage called trigger as a single-axis input controlled by the index finger, regardless of which XR platform you use. You can use InputFeatureUsage to get the trigger state by name, so you don’t need to set up an axis (or a button on some XR platforms) for the conventional Unity Input system.

XR input mappings

The following table lists the standard controller InputFeatureUsage names and how they map to the controllers of popular XR systems:

See XR.Input.CommonUsages for a definition of each InputFeatureUsage.

Accessing input devices

An InputDevice represents any physical device, such as a controller, cellular phone, or headset, and can contain information on device tracking, buttons, joysticks, and other input controls. See InputDevice for more information on the InputDevice API.

Use the XR.InputDevices class to access input devices (such as controllers and trackers) that are currently connected to the XR system. Use InputDevices.GetDevices to get a list of all connected devices:

var inputDevices = new List<UnityEngine.XR.InputDevice>();
UnityEngine.XR.InputDevices.GetDevices(inputDevices);

foreach (var device in inputDevices)
{
    Debug.Log(string.Format("Device found with name '{0}' and role '{1}'", device.name, device.role.ToString()));
}

An InputDevice remains valid across frames until the XR system disconnects it. Use the InputDevice.IsValid property to determine whether an InputDevice still represents an active controller.

Accessing input devices by role

A device role describes the general function of an input device. Use the InputDeviceRole enumeration to specify a device role. The defined roles are:

• GameController: a console-style game controllerA device to control objects and characters in a game.
  See in Glossary.
• Generic: A device that represents the core XR device, such as a head-mounted display or mobile device.
• HardwareTracker: a tracking device.
• LeftHanded: a device associated with the user’s left hand.
• RightHanded: a device associated with the user’s right hand.
• TrackingReference: a device that tracks other devices, such as an Oculus tracking cameraA component which creates an image of a particular viewpoint in your scene. The output is either drawn to the screen or captured as a texture. More info
  See in Glossary.

The underlying XR SDK reports these roles, and different providers can organize their device roles differently. Additionally, a user can switch hands, so the role assignment might not match the hand the user is using to hold the input device. For example, a user must set up the Daydream controller as right or left-handed, but can choose to hold the controller in the opposite hand.

GetDevicesWithRole provides a list of any devices with a specific InputDeviceRole. For example, you can use InputDeviceRole.GameController to get any connected GameController devices:

var gameControllers = new List<UnityEngine.XR.InputDevice>();
UnityEngine.XR.InputDevices.GetDevicesWithRole(UnityEngine.XR.InputDeviceRole.GameController, gameControllers);

foreach (var device in gameControllers)
{
    Debug.Log(string.Format("Device name '{0}' has role '{1}'", device.name, device.role.ToString()));
}

Accessing input devices by XR node

XR nodes represent the physical points of reference in the XR system. The user’s head position, their right and left hands, and a tracking reference such as an Oculus camera are all XR nodes. The XRNode enumeration defines the available nodes. The defined nodes are:

• CenterEye: a point midway between the pupils of the user’s eyes.

• GameController: a console-style game controller. Multiple game controller nodes can exist.

• HardwareTracker: a hardware tracking device, typically attached to the user or a physical item. Multiple hardware tracker nodes can exist.

• Head: the center point of the user’s head, as calculated by the XR system.

• LeftEye: the user’s left eye.

• LeftHand: the user’s left hand.

• RightEye: the user’s right eye.

• RightHand: the user’s right hand.

• TrackingReference: a tracking reference point, such as the Oculus camera. Multiple tracking reference nodes can exist.

Use InputDevices.GetDevicesAtXRNode to get a list of devices associated with a specific XRNode. The following example demonstrates how to get a left-handed controller:

var leftHandDevices = new List<UnityEngine.XR.InputDevice>();
UnityEngine.XR.InputDevices.GetDevicesAtXRNode(UnityEngine.XR.XRNode.LeftHand, leftHandDevices);

if(leftHandDevices.Count == 1)
{
    UnityEngine.XR.InputDevice device = leftHandDevices[0];
    Debug.Log(string.Format("Device name '{0}' with role '{1}'", device.name, device.role.ToString()));
}
else if(leftHandDevices.Count > 1)
{
    Debug.Log("Found more than one left hand!");
}

Accessing input features on an input device

You can read an input feature, such as the state of a trigger button, from a specific InputDevice. To read the state of the right trigger, first get an instance of the right-handed device using InputDeviceRole.RightHanded or XRNode.RightHand. Once you have the correct device, use the InputDevice.TryGetFeatureValue function to access the current state.

TryGetFeatureValue() attempts to access the current value of a feature, but can fail if the current device does not support the specified feature or the device is invalid (a controller is no longer active). The function returns true if it successfully retrieves the specified feature value, and returns false if it fails.

To get a particular button, touch input, or joystick axis value, use the CommonUsages class. CommonUsages includes each InputFeatureUsage in the XR input mapping table, as well as tracking features like position and rotation. The following code example uses CommonUsages.triggerButton to detect whether the player is currently pulling the trigger button on a particular InputDevice instance:

bool triggerValue;
if (device.TryGetFeatureValue(UnityEngine.XR.CommonUsages.triggerButton, out triggerValue) && triggerValue)
{
    Debug.Log("Trigger button is pressed");
}

You can also use the InputDevice.TryGetFeatureUsages function to get a list of every InputFeatureUsage that a device provides. This function returns a list of InputFeatureUsage items, which have a type and name property describing the feature. The following example enumerates all of the Boolean features provided by a given input device:

var inputFeatures = new List<UnityEngine.XR.InputFeatureUsage>();
if (device.TryGetFeatureUsages(inputFeatures))
{
    foreach (var feature in inputFeatures)
    {
        if (feature.type == typeof(bool))
        {
            bool featureValue;
            if (device.TryGetFeatureValue(feature.As<bool>(), out featureValue))
            {
                Debug.Log(string.Format("Bool feature '{0}''s value is '{1}'", feature.name, featureValue.ToString()));
            }
        }
    }
}

Example for primaryButton

Different controller configurations can provide access to different features; such as multiple controllers on one system, different controllers on different systems, or different buttons on the same controllers with different SDKs. This diversity makes it more complicated to support input from a range of XR systems. The Unity InputFeatureUsage API helps you get input in an XR platform-agnostic way.

The following example accesses the InputFeatureUsage called primaryButton, no matter which controller or input device provides it. The example includes a class that scans the available devices for the primaryButton. The class monitors the value of the feature on any connected device and if the value changes, the class dispatches a UnityEvent.

To use this class, add it as a component to any GameObject in the Scene.

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events;
using UnityEngine.XR;

[System.Serializable]
public class PrimaryButtonEvent : UnityEvent<bool>{}

public class PrimaryButtonWatcher : MonoBehaviour
{
    public PrimaryButtonEvent primaryButtonPress;
    
    private bool lastButtonState = false;
    private List<UnityEngine.XR.InputDevice> allDevices;
    private List<UnityEngine.XR.InputDevice> devicesWithPrimaryButton;
    
    void Start()
    {
        if(primaryButtonPress == null)
        {
            primaryButtonPress = new PrimaryButtonEvent();
        }
        allDevices = new List<UnityEngine.XR.InputDevice>();
        devicesWithPrimaryButton = new List<UnityEngine.XR.InputDevice>();
        InputTracking.nodeAdded += InputTracking_nodeAdded;
    }

    // check for new input devices when new XRNode is added
    private void InputTracking_nodeAdded(XRNodeState obj)
    {
        updateInputDevices();
    }

    void Update()
    {
        bool tempState = false;
        bool invalidDeviceFound = false;
        foreach(var device in devicesWithPrimaryButton)
        {
            bool primaryButtonState = false;
            tempState = device.isValid // the device is still valid
                        && device.TryGetFeatureValue(CommonUsages.primaryButton, out primaryButtonState) // did get a value
                        && primaryButtonState // the value we got
                        || tempState; // cumulative result from other controllers
            if (!device.isValid)
                invalidDeviceFound = true;
        }

        if (tempState != lastButtonState) // Button state changed since last frame
        {
            primaryButtonPress.Invoke(tempState);
            lastButtonState = tempState;
        }

        if (invalidDeviceFound || devicesWithPrimaryButton.Count == 0) // refresh device lists
            updateInputDevices();
    }

    // find any devices supporting the desired feature usage
    void updateInputDevices()
    {
        devicesWithPrimaryButton.Clear();
        UnityEngine.XR.InputDevices.GetDevices(allDevices);
        bool discardedValue;
        foreach (var device in allDevices)
        {
            if(device.TryGetFeatureValue(CommonUsages.primaryButton, out discardedValue))
            {
                devicesWithPrimaryButton.Add(device); // Add any devices that have a primary button.
            }
        }
    }
}

The following PrimaryReactor class uses the PrimaryButtonWatcher to detect when you press a primary button and, in response to a press, rotates its parent GameObject. To use this class, add it to a visible GameObject, such as a Cube, and drag the PrimaryButtonWatcher reference to the watcher property.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PrimaryReactor : MonoBehaviour
{
    public PrimaryButtonWatcher watcher;
    public bool IsPressed = false; // used to display button state in the Unity __Inspector__A Unity window that displays information about the currently selected GameObject, Asset or Project Settings, alowing you to inspect and edit the values. [More info](UsingTheInspector.html)<span class="tooltipGlossaryLink">See in [Glossary](Glossary.html#Inspector)</span> window
    public Vector3 rotationAngle = new Vector3(45, 45, 45);
    public float rotationDuration = 0.25f; // seconds
    private __Quaternion__Unity's standard way of representing rotations as data. When writing code that deals with rotations, you should usually use the Quaternion class and its methods. [More info](QuaternionAndEulerRotationsInUnity.html)<span class="tooltipGlossaryLink">See in [Glossary](Glossary.html#Quaternion)</span> offRotation;
    private Quaternion onRotation;
    private Coroutine rotator;

    void Start()
    {
        watcher.primaryButtonPress.AddListener(onPrimaryButtonEvent);
        offRotation = this.transform.rotation;
        onRotation = Quaternion.Euler(rotationAngle) * offRotation;
    }

    public void onPrimaryButtonEvent(bool pressed)
    {
        IsPressed = pressed;
        if (rotator != null)
            StopCoroutine(rotator);
        if (pressed)
            rotator = StartCoroutine(AnimateRotation(this.transform.rotation, onRotation));
        else
            rotator = StartCoroutine(AnimateRotation(this.transform.rotation, offRotation));
    }

    private IEnumerator AnimateRotation(Quaternion fromRotation, Quaternion toRotation)
    {
        float t = 0;
        while(t < rotationDuration)
        {
            transform.rotation = Quaternion.Lerp(fromRotation, toRotation, t/rotationDuration);
            t += Time.deltaTime;
            yield return null;
        }
    }
}

XR input through the legacy input system

You can poll XR input features via the legacy input system by using the appropriate legacy input indices from the XR input mappings table. Create an axis mapping in Edit > Settings > Input to add the appropriate mapping from input name to axis index for the platform device’s feature. To retrieve the button or axis value, use Input.GetAxis or Input.GetButton and pass in the now-mapped axis or button name.

For more information about how to use the button and joystick axes, see the documentation on Conventional game input.

Haptics

You can send haptic events to an InputDevice. Unity supports haptics as either a simple impulse with amplitude and duration, or as a buffer of data.

Not all platforms support all types of haptics, but you can query a device for haptic capabilities. The following example gets an input device for the right hand, checks to see if the device is capable of haptics, and then plays back an impulse if it is capable:

List<UnityEngine.XR.InputDevice> devices = new List<UnityEngine.XR.InputDevice>(); 

UnityEngine.XR.InputDevices.GetDevicesWithRole(UnityEngine.XR.InputDeviceRole.RightHanded, devices);

foreach (var device in devices)
{
    UnityEngine.XR.HapticCapabilities capabilities;
    if (device.TryGetHapticCapabilities(out capabilities))
    {
            if (capabilities.supportsImpulse)
            {
                uint channel = 0;
                float amplitude = 0.5f;
                float duration = 1.0f;
                device.SendHapticImpulse(channel, amplitude, duration);
            }
    }
}

• New functionality and behaviour in 2019.1 NewIn20191