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

TrackingSubsystem<XRTrackedImage, XRImageTrackingSubsystemDescriptor>.GetChanges(Allocator)

XRSubsystem<XRImageTrackingSubsystemDescriptor>.running

XRSubsystem<XRImageTrackingSubsystemDescriptor>.OnDestroy()

XRSubsystem<XRImageTrackingSubsystemDescriptor>.Start()

XRSubsystem<XRImageTrackingSubsystemDescriptor>.Stop()

Subsystem<XRImageTrackingSubsystemDescriptor>.SubsystemDescriptor

Subsystem.Destroy()

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

currentMaxNumberOfMovingImages

The current maximum number of moving images to track. This may be different from requestedMaxNumberOfMovingImages.

Declaration

public int currentMaxNumberOfMovingImages { get; }

Property Value

Type	Description
Int32

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

OnStart()

OnStop()

XRReferenceImageLibrary

MutableRuntimeReferenceImageLibrary

provider

The provider created by the implementation that contains the required image tracking functionality.

Declaration

protected XRImageTrackingSubsystem.Provider provider { get; }

Property Value

Type	Description
XRImageTrackingSubsystem.Provider

requestedMaxNumberOfMovingImages

The requested maximum number of moving images to track.

Declaration

public int requestedMaxNumberOfMovingImages { get; set; }

Property Value

Type	Description
Int32

Exceptions

Type	Condition
NotSupportedException	Thrown if the subsystem does not support tracking moving images. Check for support of this feature with supportsMovingImages.

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

RuntimeReferenceImageLibrary

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 sealed override 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 sealed override void OnStop()

Overrides

UnityEngine.XR.ARSubsystems.XRSubsystem<UnityEngine.XR.ARSubsystems.XRImageTrackingSubsystemDescriptor>.OnStop()