Class XRAnchorSubsystem

This subsystem provides information regarding anchors. An anchor is a pose (position and rotation) in the physical environment that is tracked by an XR device. Anchors are updated as the device refines its understanding of the environment, allowing you to reliably place virtual content at a real-world pose.

Inheritance

object

SubsystemWithProvider

SubsystemWithProvider<XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>

TrackingSubsystem<XRAnchor, XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>

XRAnchorSubsystem

SimulationAnchorSubsystem

Implements

ISubsystem

Inherited Members

TrackingSubsystem<XRAnchor, XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>.GetChanges(Allocator)

SubsystemWithProvider<XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>.OnCreate()

SubsystemWithProvider<XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>.OnStart()

SubsystemWithProvider<XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>.OnStop()

SubsystemWithProvider<XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>.OnDestroy()

SubsystemWithProvider<XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>.subsystemDescriptor

SubsystemWithProvider<XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>.provider

SubsystemWithProvider.Start()

SubsystemWithProvider.OnStart()

SubsystemWithProvider.Stop()

SubsystemWithProvider.OnStop()

SubsystemWithProvider.Destroy()

SubsystemWithProvider.OnDestroy()

SubsystemWithProvider.running

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: UnityEngine.XR.ARSubsystems

Assembly: Unity.XR.ARSubsystems.dll

Syntax

public class XRAnchorSubsystem : TrackingSubsystem<XRAnchor, XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>, ISubsystem

Remarks

This is a base class with an abstract provider type to be implemented by provider plug-in packages. This class itself does not implement anchor tracking.

Constructors

XRAnchorSubsystem()

Do not invoke this constructor directly.

Declaration

public XRAnchorSubsystem()

Remarks

If you are implementing your own custom subsystem Lifecycle management, use the SubsystemManager to enumerate the available XRAnchorSubsystemDescriptors, then call XRAnchorSubsystemDescriptor.Register() on the desired descriptor.

Methods

GetChanges(Allocator)

Get the changes to anchors (added, updated, and removed) since the last call to this method.

Declaration

public override TrackableChanges<XRAnchor> GetChanges(Allocator allocator)

Parameters

Type	Name	Description
Allocator	allocator	An allocator to use for the NativeArrays in TrackableChanges<T>.

Returns

Type	Description
TrackableChanges<XRAnchor>	Changes since the last call to this method.

Overrides

TrackingSubsystem<XRAnchor, XRAnchorSubsystem, XRAnchorSubsystemDescriptor, XRAnchorSubsystem.Provider>.GetChanges(Allocator)

TryAddAnchor(Pose, out XRAnchor)

Attempts to create a new anchor at the given pose.

Declaration

public bool TryAddAnchor(Pose pose, out XRAnchor anchor)

Parameters

Type	Name	Description
Pose	pose	The pose, in session space, of the new anchor.
XRAnchor	anchor	The new anchor. Only valid if this method returns true.

Returns

Type	Description
bool	true if the output anchor was added. Otherwise, false.

See Also

supportsSynchronousAdd

TryAddAnchorAsync(Pose)

Attempts to create a new anchor at the given pose.

Declaration

public Awaitable<Result<XRAnchor>> TryAddAnchorAsync(Pose pose)

Parameters

Type	Name	Description
Pose	pose	The pose, in session space, of the new anchor.

Returns

Type	Description
Awaitable<Result<XRAnchor>>	The result of the async operation. You are responsible to await this result.

TryAttachAnchor(TrackableId, Pose, out XRAnchor)

Attempts to create a new anchor "attached" to the trackable with id trackableToAffix. The behavior of the anchor depends on the type of trackable to which this anchor is attached.

Declaration

public bool TryAttachAnchor(TrackableId trackableToAffix, Pose pose, out XRAnchor anchor)

Parameters

Type	Name	Description
TrackableId	trackableToAffix	The id of the trackable to which to attach.
Pose	pose	The pose, in session space, of the anchor to create.
XRAnchor	anchor	The new anchor. Only valid if this method returns true.

Returns

Type	Description
bool	true if the new anchor was added. Otherwise, false.

TryEraseAnchorAsync(SerializableGuid, CancellationToken)

Attempts to erase the persistent saved data associated with an anchor given its persistent anchor GUID.

Declaration

public Awaitable<XRResultStatus> TryEraseAnchorAsync(SerializableGuid savedAnchorGuid, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
SerializableGuid	savedAnchorGuid	A persistent anchor GUID created by TrySaveAnchorAsync(TrackableId, CancellationToken).
CancellationToken	cancellationToken	An optional CancellationToken that you can use to cancel the operation in progress if the loaded provider supportsAsyncCancellation.

Returns

Type	Description
Awaitable<XRResultStatus>	The result of the async operation. You are responsible to await this result.

See Also

supportsEraseAnchor

TryEraseAnchorsAsync(NativeArray<SerializableGuid>, Allocator, CancellationToken)

Attempts to erase the persistent saved data associated with a batch of anchors given their persistent anchor GUIDs.

Declaration

public Awaitable<NativeArray<XREraseAnchorResult>> TryEraseAnchorsAsync(NativeArray<SerializableGuid> savedAnchorGuids, Allocator allocator, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
NativeArray<SerializableGuid>	savedAnchorGuids	The persistent anchor GUIDs created by TrySaveAnchorAsync(TrackableId, CancellationToken) or TrySaveAnchorsAsync(NativeArray<TrackableId>, Allocator, CancellationToken).
Allocator	allocator	The allocator of the returned NativeArray.
CancellationToken	cancellationToken	An optional CancellationToken that you can use to cancel the operation in progress if the loaded provider supportsAsyncCancellation.

Returns

Type	Description
Awaitable<NativeArray<XREraseAnchorResult>>	The result of the async operation. You are responsible to await this result.

Exceptions

Type	Condition
NotSupportedException	Thrown if supportsEraseAnchor is false for this provider.

TryGetSavedAnchorIdsAsync(Allocator, CancellationToken)

Attempts to get a NativeArray containing all saved persistent anchor GUIDs.

Declaration

public Awaitable<Result<NativeArray<SerializableGuid>>> TryGetSavedAnchorIdsAsync(Allocator allocator, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
Allocator	allocator	The allocation strategy to use for the resulting NativeArray.
CancellationToken	cancellationToken	An optional CancellationToken that you can use to cancel the operation in progress if the loaded provider supportsAsyncCancellation.

Returns

Type	Description
Awaitable<Result<NativeArray<SerializableGuid>>>	The result of the async operation, containing a NativeArray of persistent anchor GUIDs allocated with the given allocator if the operation succeeded. You are responsible to await this result.

See Also

supportsGetSavedAnchorIds

TryLoadAnchorAsync(SerializableGuid, CancellationToken)

Attempts to load an anchor given its persistent anchor GUID.

Declaration

public Awaitable<Result<XRAnchor>> TryLoadAnchorAsync(SerializableGuid savedAnchorGuid, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
SerializableGuid	savedAnchorGuid	A persistent anchor GUID created by TrySaveAnchorAsync(TrackableId, CancellationToken).
CancellationToken	cancellationToken	An optional CancellationToken that you can use to cancel the operation in progress if the loaded provider supportsAsyncCancellation.

Returns

Type	Description
Awaitable<Result<XRAnchor>>	The result of the async operation, containing the newly added anchor if the operation succeeded. You are responsible to await this result.

See Also

supportsLoadAnchor

TryLoadAnchorsAsync(NativeArray<SerializableGuid>, Allocator, Action<NativeArray<XRLoadAnchorResult>>, CancellationToken)

Attempts to load a batch of anchors given their persistent anchor GUIDs.

Declaration

public Awaitable<NativeArray<XRLoadAnchorResult>> TryLoadAnchorsAsync(NativeArray<SerializableGuid> savedAnchorGuidsToLoad, Allocator allocator, Action<NativeArray<XRLoadAnchorResult>> incrementalResultsCallback, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
NativeArray<SerializableGuid>	savedAnchorGuidsToLoad	The persistent anchor GUIDs to load that were created by TrySaveAnchorsAsync(NativeArray<TrackableId>, Allocator, CancellationToken) or TrySaveAnchorAsync(TrackableId, CancellationToken).
Allocator	allocator	The allocator used for the returned NativeArray.
Action<NativeArray<XRLoadAnchorResult>>	incrementalResultsCallback	A callback method that will be called when any requested anchors are loaded. Pass a null argument for this parameter to ignore it. The NativeArray passed to you uses Allocation.Temp.
CancellationToken	cancellationToken	An optional CancellationToken that you can use to cancel the operation in progress if the loaded provider supportsAsyncCancellation.

Returns

Type	Description
Awaitable<NativeArray<XRLoadAnchorResult>>	The result of the async operation. You are responsible to await this result.

Remarks

The order in which anchors are loaded may not match the enumeration order of savedAnchorGuidsToLoad. To check if an anchor loaded successfully, check the resultStatus.

Exceptions

Type	Condition
NotSupportedException	Thrown if supportsLoadAnchor is false for this provider.

TryRemoveAnchor(TrackableId)

Attempts to remove an existing anchor with TrackableId anchorId.

Declaration

public bool TryRemoveAnchor(TrackableId anchorId)

Parameters

Type	Name	Description
TrackableId	anchorId	The id of an existing anchor to remove.

Returns

Type	Description
bool	true if the anchor was removed. Otherwise, false.

TrySaveAnchorAsync(TrackableId, CancellationToken)

Attempts to persistently save the given anchor so that it can be loaded in a future AR session. Use the SerializableGuid returned by this method as an input parameter to TryLoadAnchorAsync(SerializableGuid, CancellationToken) or TryEraseAnchorAsync(SerializableGuid, CancellationToken).

Declaration

public Awaitable<Result<SerializableGuid>> TrySaveAnchorAsync(TrackableId anchorId, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
TrackableId	anchorId	The TrackableId of the anchor to save.
CancellationToken	cancellationToken	An optional CancellationToken that you can use to cancel the operation in progress if the loaded provider supportsAsyncCancellation.

Returns

Type	Description
Awaitable<Result<SerializableGuid>>	The result of the async operation, containing a new persistent anchor GUID if the operation succeeded. You are responsible to await this result.

See Also

supportsSaveAnchor

TrySaveAnchorsAsync(NativeArray<TrackableId>, Allocator, CancellationToken)

Attempts to persistently save the given anchors so that they can be loaded in a future AR session. Use the SerializableGuids returned from this method as an input to TryLoadAnchorsAsync(NativeArray<SerializableGuid>, Allocator, Action<NativeArray<XRLoadAnchorResult>>, CancellationToken) or TryEraseAnchorsAsync(NativeArray<SerializableGuid>, Allocator, CancellationToken).

Declaration

public Awaitable<NativeArray<XRSaveAnchorResult>> TrySaveAnchorsAsync(NativeArray<TrackableId> anchorIdsToSave, Allocator allocator, CancellationToken cancellationToken = default)

Parameters

Type	Name	Description
NativeArray<TrackableId>	anchorIdsToSave	The TrackableIds of the anchors to save. You can create an anchor using TryAddAnchorAsync(Pose).
Allocator	allocator	The allocator used for the returned NativeArray of saved anchor GUIDs.
CancellationToken	cancellationToken	An optional CancellationToken that you can use to cancel the operation in progress if the loaded provider supportsAsyncCancellation.

Returns

Type	Description
Awaitable<NativeArray<XRSaveAnchorResult>>	The result of the async operation. You are responsible to await this result.

Exceptions

Type	Condition
NotSupportedException	Thrown if supportsSaveAnchor is false for this provider.

Implements

ISubsystem