Class XRImageTrackingSubsystem

A subsystem for detecting and tracking a preconfigured set of images in the environment.

Inheritance
Object
Subsystem
Subsystem<XRImageTrackingSubsystemDescriptor>
XRSubsystem<XRImageTrackingSubsystemDescriptor>
TrackingSubsystem<XRTrackedImage, XRImageTrackingSubsystemDescriptor>
XRImageTrackingSubsystem
Inherited Members
Namespace: UnityEngine.XR.ARSubsystems
Syntax
public abstract class XRImageTrackingSubsystem : TrackingSubsystem<XRTrackedImage, XRImageTrackingSubsystemDescriptor>, ISubsystem

Constructors

XRImageTrackingSubsystem()

Constructs a subsystem. Do not invoked directly; call Create on the XRImageTrackingSubsystemDescriptor instead.

Declaration
public XRImageTrackingSubsystem()

Properties

imageLibrary

Get or set the reference image library. This is the set of images to look for in the environment.

Declaration
public RuntimeReferenceImageLibrary imageLibrary { get; set; }
Property Value
Type Description
RuntimeReferenceImageLibrary
Remarks

A RuntimeReferenceImageLibrary is created at runtime and may be modifiable (see MutableRuntimeReferenceImageLibrary). A RuntimeReferenceImageLibrary may be created from an XRReferenceImageLibrary using CreateRuntimeLibrary(XRReferenceImageLibrary).

Exceptions
Type Condition
ArgumentNullException

Thrown if the subsystem has been started, and you attempt to set the image library to null.
See Also

maxNumberOfMovingImages

Declaration
public int maxNumberOfMovingImages { set; }
Property Value
Type Description
Int32

Methods

CreateProvider()

Create an implementation of the XRImageTrackingSubsystem.Provider class. This will only be called once.

Declaration
protected abstract XRImageTrackingSubsystem.Provider CreateProvider()
Returns
Type Description
XRImageTrackingSubsystem.Provider

An instance of the XRImageTrackingSubsystem.Provider interface.

CreateRuntimeLibrary(XRReferenceImageLibrary)

Creates a RuntimeReferenceImageLibrary from an existing XRReferenceImageLibrary or an empty library if serializedLibrary is null. Use this to construct the runtime representation of an XRReferenceImageLibrary.

Declaration
public RuntimeReferenceImageLibrary CreateRuntimeLibrary(XRReferenceImageLibrary serializedLibrary)
Parameters
Type Name Description
XRReferenceImageLibrary serializedLibrary

An existing XRReferenceImageLibrary created at edit time, or null to create an empty image library.
Returns
Type Description
RuntimeReferenceImageLibrary

A new RuntimeReferenceImageLibrary representing the deserialized version of serializedLibrary or an empty library if serializedLibrary is null.
Remarks

If the subsystem supports runtime mutable libraries (see supportsMutableLibrary), then the returned library will be a MutableRuntimeReferenceImageLibrary.

See Also

GetChanges(Allocator)

Retrieve the changes in the state of tracked images (added, updated, removed) since the last call to GetChanges.

Declaration
public override TrackableChanges<XRTrackedImage> GetChanges(Allocator allocator)
Parameters
Type Name Description
Allocator allocator

The allocator to use for the returned set of changes.
Returns
Type Description
TrackableChanges<XRTrackedImage>

The set of tracked image changes (added, updated, removed) since the last call to this method.
Overrides
UnityEngine.XR.ARSubsystems.TrackingSubsystem<UnityEngine.XR.ARSubsystems.XRTrackedImage, UnityEngine.XR.ARSubsystems.XRImageTrackingSubsystemDescriptor>.GetChanges(Unity.Collections.Allocator)

OnDestroyed()

Destroys the subsystem.

Declaration
protected override sealed void OnDestroyed()
Overrides
UnityEngine.XR.ARSubsystems.XRSubsystem<UnityEngine.XR.ARSubsystems.XRImageTrackingSubsystemDescriptor>.OnDestroyed()

OnStart()

Starts the subsystem, that is, start detecting images in the scene. imageLibrary must not be null.

Declaration
protected override void OnStart()
Overrides
UnityEngine.XR.ARSubsystems.XRSubsystem<UnityEngine.XR.ARSubsystems.XRImageTrackingSubsystemDescriptor>.OnStart()
Exceptions
Type Condition
InvalidOperationException

Thrown if imageLibrary is null.

OnStop()

Stops the subsystem, that is, stops detecting and tracking images.

Declaration
protected override sealed void OnStop()
Overrides
UnityEngine.XR.ARSubsystems.XRSubsystem<UnityEngine.XR.ARSubsystems.XRImageTrackingSubsystemDescriptor>.OnStop()