Class ARSession

Controls the lifecycle and configuration options for an AR session. There is only one active session. If you have multiple ARSession components, they all talk to the same session and will conflict with each other.

Enabling or disabling the ARSession will start or stop the session, respectively.

Inheritance
Object
SubsystemLifecycleManager<XRSessionSubsystem, XRSessionSubsystemDescriptor>
ARSession
Inherited Members
Namespace: UnityEngine.XR.ARFoundation
Syntax
public sealed class ARSession : SubsystemLifecycleManager<XRSessionSubsystem, XRSessionSubsystemDescriptor>

Properties

attemptUpdate

If the device supports XR but does not have the necessary software, some platforms allow prompting the user to install or update the software. If attemptUpdate is true, a software update will be attempted. If the appropriate software is not installed or out of date, and attemptUpdate is false, then AR will not be available.

Declaration
public bool attemptUpdate { get; set; }
Property Value
Type Description
Boolean

frameRate

Get the number of AR frames produced per second, or null if the frame rate cannot be determined.

Declaration
public int? frameRate { get; }
Property Value
Type Description
Nullable<Int32>

matchFrameRate

If True, the session will block execution until a new AR frame is available and set Application.targetFrameRate to match the native update frequency of the AR session. Otherwise, the AR session is updated indpendently of the Unity frame.

Declaration
public bool matchFrameRate { get; set; }
Property Value
Type Description
Boolean
Remarks

If enabled with a simple scene, the ARSession.Update may appear to take a long time. This is simply waiting for the next AR frame, similar to the way Unity will WaitForTargetFPS at the end of a frame. If the rest of the Unity frame takes non-trivial time, then the next ARSession.Update will take a proportionally less amount of time.

This option does three things: - Enables a setting on the XRSessionSubsystem which causes the update to block until the next AR frame is ready. - Sets Application.targetFrameRate to the session's preferred update rate. - Sets QualitySettings.vSyncCount to zero

notTrackingReason

The reason AR tracking was lost.

Declaration
public static NotTrackingReason notTrackingReason { get; }
Property Value
Type Description
NotTrackingReason

state

The state of the entire system. Use this to determine the status of AR availability and installation.

Declaration
public static ARSessionState state { get; }
Property Value
Type Description
ARSessionState

Methods

CheckAvailability()

Start checking the availability of XR on the current device.

Declaration
public static IEnumerator CheckAvailability()
Returns
Type Description
IEnumerator

An IEnumerator used for a coroutine.
Remarks

The availability check may be asynchronous, so this is implemented as a coroutine. It is safe to call this multiple times; if called a second time while an availability check is being made, it returns a new coroutine which waits on the first.

Install()

Begin installing AR software on the current device (if supported).

Declaration
public static IEnumerator Install()
Returns
Type Description
IEnumerator

An IEnumerator used for a coroutine.
Remarks

Installation may be asynchronous, so this is implemented as a coroutine. It is safe to call this multiple times, but you must first call CheckAvailability().

You must call CheckAvailability() before tring to Install and the must not be or this method will throw.

OnDestroy()

Declaration
protected override void OnDestroy()
Overrides
UnityEngine.XR.ARFoundation.SubsystemLifecycleManager<XRSessionSubsystem, XRSessionSubsystemDescriptor>.OnDestroy()

OnDisable()

Declaration
protected override void OnDisable()
Overrides
UnityEngine.XR.ARFoundation.SubsystemLifecycleManager<XRSessionSubsystem, XRSessionSubsystemDescriptor>.OnDisable()

OnEnable()

Creates and initializes the session subsystem. Begins checking for availability.

Declaration
protected override void OnEnable()
Overrides
UnityEngine.XR.ARFoundation.SubsystemLifecycleManager<XRSessionSubsystem, XRSessionSubsystemDescriptor>.OnEnable()

Reset()

Resets the AR Session. This destroys the current session, including all trackables, and then establishes a new session.

Declaration
public void Reset()

Events

stateChanged

This event is invoked whenever the changes.

Declaration
public static event Action<ARSessionStateChangedEventArgs> stateChanged
Event Type
Type Description
Action<ARSessionStateChangedEventArgs>