GARSession

ARCore session class.

Adds ARCore features to an app using ARKit. All NSError's returned by methods in this class have domain GARSessionErrorDomain and code a value of GARSessionErrorCode. For Augmented Faces, see GARAugmentedFaceSession. See categories of this class for other features. Each feature must be turned on by using setConfiguration:error: (GARSession) prior to use.

Summary

Inheritance

Inherits from: NSObject

Properties
currentFramePair	GARFramePair * The most recent frame pair, containing the most recent ARFrame passed into update:error: and the corresponding returned GARFrame.
delegate	id< GARSessionDelegate > The delegate for receiving callbacks about the GARSession.
delegateQueue	dispatch_queue_t The dispatch queue on which the delegate receives calls.

Public static methods
sessionWithAPIKey:bundleIdentifier:error:	nullable instancetype Creates a GARSession with an API key and bundle identifier.
sessionWithError:	nullable instancetype Creates a GARSession.

Public methods
checkVPSAvailabilityAtCoordinate:completionHandler:	GARVPSAvailabilityFuture * Gets the availability of the Visual Positioning System (VPS) at a specified horizontal position.
createAnchorOnStreetscapeGeometry:transform:error:	nullable GARAnchor * Creates an anchor at the given transform in the world coordinate space, attached to this GARStreetscapeGeometry, and acquires a reference to it.
createAnchorWithCoordinate:altitude:eastUpSouthQAnchor:error:	nullable GARAnchor * Creates a Geospatial anchor at the specified geodetic location and orientation relative to the Earth.
createAnchorWithCoordinate:altitudeAboveRooftop:eastUpSouthQAnchor:completionHandler:error:	nullable GARCreateAnchorOnRooftopFuture * Asynchronously creates a Rooftop anchor at the specified horizontal position and altitude relative to the horizontal position's rooftop.
createAnchorWithCoordinate:altitudeAboveTerrain:eastUpSouthQAnchor:completionHandler:error:	nullable GARCreateAnchorOnTerrainFuture * Asynchronously creates a Terrain anchor at a specified horizontal position and altitude relative to the horizontal position's terrain.
createAnchorWithCoordinate:altitudeAboveTerrain:eastUpSouthQAnchor:error:	nullable GARAnchor * Creates a Terrain anchor at the specified geodetic location, altitude relative to the horizontal position’s terrain and orientation relative to the Earth.
estimateFeatureMapQualityForHosting:error:	GARFeatureMapQuality Estimates the quality of the visual features seen by ARCore in the preceding few seconds and visible from the provided camera transform.
geospatialTransformFromTransform:error:	nullable GARGeospatialTransform * Converts the provided transform to a GARGeospatialTransform with respect to the Earth.
hostCloudAnchor:TTLDays:completionHandler:error:	nullable GARHostCloudAnchorFuture * Uses the transform and other data from anchor to host a new Cloud Anchor.
hostCloudAnchor:TTLDays:error:	nullable GARAnchor * This will create a new Cloud Anchor with a given lifetime in days, using the transform of the provided anchor.
hostCloudAnchor:error:	nullable GARAnchor * Hosts a new Cloud Anchor based on an ARAnchor.
isGeospatialModeSupported:	BOOL Determines whether the given geospatial mode is supported on the current device and OS version.
isSemanticModeSupported:	BOOL Determines whether the given GARSemanticMode is supported on the current device and OS version.
raycastStreetscapeGeometry:direction:error:	nullable NSArray< GARStreetscapeGeometryRaycastResult * > * Performs a raycast against Streetscape Geometry loaded by the scene.
removeAnchor:	void Removes an anchor from the session.
resolveCloudAnchorWithIdentifier:completionHandler:error:	nullable GARResolveCloudAnchorFuture * Attempts to resolve a Cloud Anchor using the provided identifier.
resolveCloudAnchorWithIdentifier:error:	nullable GARAnchor * Resolves a Cloud Anchor with a given identifier.
setAuthToken:	void Provide an auth token to use when authenticating with Google Cloud Services.
setConfiguration:error:	void Sets the configuration for the session.
transformFromGeospatialCoordinate:altitude:eastUpSouthQTarget:error:	matrix_float4x4 Converts the provided Earth specified horizontal position, altitude and rotation with respect to an east-up-south coordinate frame to a local transform in world coordinate space.
update:error:	nullable GARFrame * Updates the GARSession with an ARFrame.

Properties

currentFramePair

@property(atomic, readonly, nullable) GARFramePair *currentFramePair;

The most recent frame pair, containing the most recent ARFrame passed into update:error: and the corresponding returned GARFrame.

delegate

@property(atomic, weak, nullable) id delegate;

The delegate for receiving callbacks about the GARSession.

delegateQueue

@property(atomic, nullable) dispatch_queue_t delegateQueue;

The dispatch queue on which the delegate receives calls.

If nil, callbacks happen on the main thread.

Public static methods

sessionWithAPIKey:bundleIdentifier:error:

+ (nullable instancetype)sessionWithAPIKey:
(NSString *) apiKey
bundleIdentifier:
(nullable NSString *) bundleIdentifier
error:
(NSError **) error

Creates a GARSession with an API key and bundle identifier.

Details
Parameters	apiKey Your API key for Google Cloud Services. bundleIdentifier The bundle identifier associated to your API key. If nil, defaults to [[NSBundle mainBundle] bundleIdentifier]. error Out parameter for an NSError. Possible errors: GARSessionErrorCodeDeviceNotCompatible - this device or OS version is not currently supported. GARSessionErrorCodeInvalidArgument - API key is nil or empty.
Returns	The new GARSession, or nil if there is an error.

sessionWithError:

+ (nullable instancetype)sessionWithError:
(NSError **) error

Creates a GARSession.

To authenticate with Google Cloud Services, use setAuthToken:.

Details
Parameters	error Out parameter for an NSError. Possible errors: GARSessionErrorCodeDeviceNotCompatible - this device or OS version is not currently supported.
Returns	The new GARSession, or nil if there is an error.

Public methods

checkVPSAvailabilityAtCoordinate:completionHandler:

- (GARVPSAvailabilityFuture *)checkVPSAvailabilityAtCoordinate:
(CLLocationCoordinate2D) coordinate
completionHandler:
(void(^)(GARVPSAvailability availability)) completionHandler

Gets the availability of the Visual Positioning System (VPS) at a specified horizontal position.

The availability of VPS in a given location helps to improve the quality of Geospatial localization and tracking accuracy.

This launches an asynchronous operation used to query the Google Cloud ARCore API. See GARFuture for information on obtaining results and cancelling the operation.

Your app must be properly set up to communicate with the Google Cloud ARCore API in order to obtain a result from this call. See Check VPS Availability for more details on setup steps and usage examples.

Details
Parameters	coordinate The coordinate at which to check availability. completionHandler Completion handler to be invoked on the Main thread, if not nil.
Returns	A handle to the async operation that can be polled or cancelled.

Provided by category GARSession(Geospatial).

createAnchorOnStreetscapeGeometry:transform:error:

- (nullable GARAnchor *)createAnchorOnStreetscapeGeometry:
(GARStreetscapeGeometry *) g
eometry
transform:
(matrix_float4x4) transform
error:
(NSError **) error

Creates an anchor at the given transform in the world coordinate space, attached to this GARStreetscapeGeometry, and acquires a reference to it.

Details
Parameters	geometry The object that this anchor will be attached to. transform The local transform in world coordinate space. error Out param for an NSError. Possible error codes: GARSessionErrorCodeIllegalState - current geospatial mode is disabled, or Streetscape Geometry mode is disabled. GARSessionErrorCodeNotTracking - Earth, Session or geometry's ARTrackingState is not GARTrackingStateTracking.
Returns	The new anchor, or nil if there was an error.

Provided by category GARSession(Geospatial).

createAnchorWithCoordinate:altitude:eastUpSouthQAnchor:error:

- (nullable GARAnchor *)createAnchorWithCoordinate:
(CLLocationCoordinate2D) coordinate
altitude:
(CLLocationDistance) altitude
eastUpSouthQAnchor:
(simd_quatf) eastUpSouthQAnchor
error:
(NSError **
) error

Creates a Geospatial anchor at the specified geodetic location and orientation relative to the Earth.

Latitude and longitude are defined by the WGS84 specification, and altitude values are defined as the elevation above the WGS84 ellipsoid in meters.

The rotation provided by eastUpSouthQAnchor is a rotation with respect to an east-up-south coordinate frame. An identity rotation will have the anchor oriented such that X+ points to the east, Y+ points up away from the center of the earth, and Z+ points to the south.

An anchor's GARAnchor.trackingState will be GARTrackingStatePaused while GAREarth is GARTrackingStatePaused. The tracking state will permanently become GARTrackingStateStopped if the GARSession configuration is set to GARGeospatialModeDisabled.

Creating anchors near the north pole or south pole is not supported. If the latitude is within 0.1° of the north pole or south pole (90° or -90 °), this function will output GARSessionErrorCodeInvalidArgument and the anchor will fail to be created.

Details
Parameters	coordinate The latitude and longitude associated with the location, specified using the WGS84 reference frame. This must not be within .1° of the North or South pole (i.e. +- 90°). altitude Altitude in reference to the WGS 84 ellipsoid, in meters. Positive values indicate altitudes above approximate sea level. Negative values indicate altitudes below approximate sea level. eastUpSouthQAnchor Represents the quaternion from the anchor to East-Up-South (EUS) coordinates (i.e., +X points East, +Y points up, and +Z points South). error Out param for an NSError. Possible error codes: GARSessionErrorCodeIllegalState - current Geospatial mode is disabled or earth has trackingState GARTrackingStateStopped. GARSessionErrorCodeInvalidArgument - latitude is not within range.
Returns	The new anchor, or nil if there was an error.

Provided by category GARSession(Geospatial).

createAnchorWithCoordinate:altitudeAboveRooftop:eastUpSouthQAnchor:completionHandler:error:

- (nullable GARCreateAnchorOnRooftopFuture *)createAnchorWithCoordinate:
(CLLocationCoordinate2D) coordinate
altitudeAboveRooftop:
(CLLocationDistance) altitudeAboveRooftop
eastUpSouthQAnchor:
(simd_quatf) eastUpSouthQAnchor
completionHandler:
(void(^)(GARAnchor *_Nullable anchor,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   GARRooftopAnchorState rooftopState)) completionHandler
error:
(NSError **) error

Asynchronously creates a Rooftop anchor at the specified horizontal position and altitude relative to the horizontal position's rooftop.

See the Rooftop anchors developer guide for more information.

The specified altitudeAboveRooftop is interpreted to be relative to the top of a building at the given horizontal location, rather than relative to the WGS84 ellipsoid. If there is no building at the given location, then the altitude is interpreted to be relative to the terrain instead. Specifying an altitude of 0 will position the anchor directly on the rooftop whereas specifying a positive altitude will position the anchor above the rooftop, against the direction of gravity.

This launches an asynchronous operation used to query the Google Cloud ARCore API. See GARFuture for information on obtaining results and cancelling the operation.

You may resolve multiple anchors at a time, but a session cannot be tracking more than 100 Rooftop or Terrain anchors at time. Attempting to resolve more than 100 Rooftop or Terrain anchors will result in GARSessionErrorCodeResourceExhausted.

Latitude and longitude are defined by the WGS84 specification, and altitude values are defined as the elevation above the WGS84 ellipsoid in meters.

The rotation provided by eastUpSouthQAnchor is a rotation with respect to an east-up-south coordinate frame. An identity rotation will have the anchor oriented such that X+ points to the east, Y+ points up away from the center of the earth, and Z+ points to the south.

An anchor's GARAnchor.trackingState will be GARTrackingStateTracking while GAREarth is GARTrackingStateTracking. The tracking state will permanently become GARTrackingStateStopped if the GARSession configuration is set to GARGeospatialModeDisabled.

Creating anchors near the north pole or south pole is not supported. If the latitude is within 0.1° of the north pole or south pole (90° or -90°), this function will output GARSessionErrorCodeInvalidArgument and the anchor will fail to be created.

Details
Parameters	coordinate The latitude and longitude associated with the location, specified using the WGS84 reference frame. This must not be within .1° of the North or South pole (i.e. +- 90°). altitudeAboveRooftop Altitude above Earth's rooftop or terrain, in meters. eastUpSouthQAnchor Represents the quaternion from the anchor to East-Up-South (EUS) coordinates (i.e., +X points East, +Y points up, and +Z points South). completionHandler Completion handler to be invoked on the Main thread, if not nil. error Out param for an NSError. Possible error codes: GARSessionErrorCodeIllegalState - current Geospatial mode is disabled or earth has trackingState GARTrackingStateStopped. GARSessionErrorCodeInvalidArgument - latitude is not within range. GARSessionErrorCodeResourceExhausted - tried to create too many Rooftop or Terrain anchors.
Returns	A handle to the async operation that can be polled or cancelled.

Provided by category GARSession(Geospatial).

createAnchorWithCoordinate:altitudeAboveTerrain:eastUpSouthQAnchor:completionHandler:error:

- (nullable GARCreateAnchorOnTerrainFuture *)createAnchorWithCoordinate:
(CLLocationCoordinate2D) coordinate
altitudeAboveTerrain:
(CLLocationDistance) altitudeAboveTerrain
eastUpSouthQAnchor:
(simd_quatf) eastUpSouthQAnchor
completionHandler:
(void(^)(GARAnchor *_Nullable anchor,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   GARTerrainAnchorState terrainState)) completionHandler
error:
(NSError **) error

Asynchronously creates a Terrain anchor at a specified horizontal position and altitude relative to the horizontal position's terrain.

See the Terrain anchors developer guide for more information.

The specified altitudeAboveTerrain is interpreted to be relative to the Earth's terrain (or floor) at the specified latitude/longitude geodetic coordinates, rather than relative to the WGS-84 ellipsoid. Specifying an altitudeAboveTerrain of 0 will position the anchor directly on the terrain whereas specifying a positive altitudeAboveTerrain will position the anchor above the terrain, against the direction of gravity.

This launches an asynchronous operation used to query the Google Cloud ARCore API. See GARFuture for information on obtaining results and cancelling the operation.

You may resolve multiple anchors at a time, but a session cannot be tracking more than 100 Rooftop or Terrain anchors at time. Attempting to resolve more than 100 Rooftop or Terrain anchors will result in GARSessionErrorCodeResourceExhausted.

Latitude and longitude are defined by the WGS84 specification, and altitude values are defined as the elevation above the WGS84 ellipsoid in meters.

The rotation provided by eastUpSouthQAnchor is a rotation with respect to an east-up-south coordinate frame. An identity rotation will have the anchor oriented such that X+ points to the east, Y+ points up away from the center of the earth, and Z+ points to the south.

An anchor's GARAnchor.trackingState will be GARTrackingStateTracking while GAREarth is GARTrackingStateTracking. The tracking state will permanently become GARTrackingStateStopped if the GARSession configuration is set to GARGeospatialModeDisabled.

Creating anchors near the north pole or south pole is not supported. If the latitude is within 0.1° of the north pole or south pole (90° or -90°), this function will output GARSessionErrorCodeInvalidArgument and the anchor will fail to be created.

Details
Parameters	coordinate The latitude and longitude associated with the location, specified using the WGS84 reference frame. This must not be within .1° of the North or South pole (i.e. +- 90°). altitudeAboveTerrain Altitude above Earth's terrain, in meters. eastUpSouthQAnchor Represents the quaternion from the anchor to East-Up-South (EUS) coordinates (i.e., +X points East, +Y points up, and +Z points South). completionHandler Completion handler to be invoked on the Main thread, if not nil. error Out param for an NSError. Possible error codes: GARSessionErrorCodeIllegalState - current Geospatial mode is disabled or earth has trackingState GARTrackingStateStopped. GARSessionErrorCodeInvalidArgument - latitude is not within range. GARSessionErrorCodeResourceExhausted - tried to create too many Rooftop or Terrain anchors.
Returns	A handle to the async operation that can be polled or cancelled.

Provided by category GARSession(Geospatial).

createAnchorWithCoordinate:altitudeAboveTerrain:eastUpSouthQAnchor:error:

- (nullable GARAnchor *)createAnchorWithCoordinate:
(CLLocationCoordinate2D) coordinate
altitudeAboveTerrain:
(CLLocationDistance) altitudeAboveTerrain
eastUpSouthQAnchor:
(simd_quatf) eastUpSouthQAnchor
error:
(NSError **
) error

Creates a Terrain anchor at the specified geodetic location, altitude relative to the horizontal position’s terrain and orientation relative to the Earth.

Terrain means the ground, or ground floor inside a building with VPS coverage.

The specified altitudeAboveTerrain is interpreted to be relative to the Earth's terrain (or floor) at the specified latitude/longitude geodetic coordinates, rather than relative to the WGS-84 ellipsoid. Specifying an altitudeAboveTerrain of 0 will position the anchor directly on the terrain (or floor) whereas specifying a positive altitudeAboveTerrain will position the anchor above the terrain (or floor), against the direction of gravity.

This function schedules a task to resolve the anchor's pose using the given parameters. You may resolve multiple anchors at a time, but a session cannot be tracking more than 100 Terrain anchors at time. Attempting to resolve more than 100 Terrain anchors will result in GARSessionErrorCodeResourceExhausted.

If this function returns error nil, the terrain anchor's GARAnchor.terrainState will be GARTerrainAnchorStateTaskInProgress, and its tracking state will be GARTrackingStatePaused. This anchor remains in this state until its pose has been successfully resolved. If the resolving task results in an error, the tracking state will be set to GARTrackingStateStopped.

Latitude and longitude are defined by the WGS84 specification, and altitude values are defined as the elevation above the WGS84 ellipsoid in meters.

The rotation provided by eastUpSouthQAnchor is a rotation with respect to an east-up-south coordinate frame. An identity rotation will have the anchor oriented such that X+ points to the east, Y+ points up away from the center of the earth, and Z+ points to the south.

An anchor's GARAnchor.trackingState will be GARTrackingStateTracking while GAREarth is GARTrackingStateTracking. The tracking state will permanently become GARTrackingStateStopped if the GARSession configuration is set to GARGeospatialModeDisabled.

Creating anchors near the north pole or south pole is not supported. If the latitude is within 0.1° of the north pole or south pole (90° or -90°), this function will output GARSessionErrorCodeInvalidArgument and the anchor will fail to be created.

Details
Parameters	coordinate The latitude and longitude associated with the location, specified using the WGS84 reference frame. This must not be within .1° of the North or South pole (i.e. +- 90°). altitudeAboveTerrain Altitude above Earth's terrain, in meters. eastUpSouthQAnchor Represents the quaternion from the anchor to East-Up-South (EUS) coordinates (i.e., +X points East, +Y points up, and +Z points South). error Out param for an NSError. Possible error codes: GARSessionErrorCodeIllegalState - current Geospatial mode is disabled or earth has trackingState GARTrackingStateStopped. GARSessionErrorCodeInvalidArgument - latitude is not within range. GARSessionErrorCodeResourceExhausted - tried to create too many Rooftop or Terrain anchors.
Returns	The new anchor, or nil if there was an error.

Provided by category GARSession(Geospatial).

estimateFeatureMapQualityForHosting:error:

- (GARFeatureMapQuality)estimateFeatureMapQualityForHosting:
(simd_float4x4) transform
error:
(NSError **) error

Estimates the quality of the visual features seen by ARCore in the preceding few seconds and visible from the provided camera transform.

Cloud Anchors hosted using higher quality features will generally result in easier and more accurately resolved Cloud Anchor transforms.

Details
Parameters	transform The camera transform to use in estimating the quality. error Out parameter for an NSError. Possible errors: GARSessionErrorCodeNotTracking - bad current ARTrackingState. GARSessionErrorCodeIllegalState - current cloud anchor mode is disabled.
Returns	The estimated quality of the visual features seen by ARCore in the preceding few seconds and visible from the provided camera transform.

Provided by category GARSession(CloudAnchors).

geospatialTransformFromTransform:error:

- (nullable GARGeospatialTransform *)geospatialTransformFromTransform:
(matrix_float4x4) transform
error:
(NSError **
) error

Converts the provided transform to a GARGeospatialTransform with respect to the Earth.

Its heading will be zero for a GARGeospatialTransform returned from this method.

Details
Parameters	transform The local transform in world coordinate space. error Out param for an NSError. Possible error codes: GARSessionErrorCodeIllegalState - current Geospatial mode is disabled or earth has trackingState GARTrackingStateStopped. GARSessionErrorCodeNotTracking - Earth's or Session's ARTrackingState is not GARTrackingStateTracking.
Returns	GARGeospatialTransform, or nil if there was an error.

Provided by category GARSession(Geospatial).

hostCloudAnchor:TTLDays:completionHandler:error:

- (nullable GARHostCloudAnchorFuture *)hostCloudAnchor:
(ARAnchor *)
 anchor
TTLDays:
(NSInteger) TTLDays
completionHandler:
(void(^)(NSString *_Nullable cloudIdentifier,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   GARCloudAnchorState cloudState)) completionHandler
error:
(NSError **) error

Uses the transform and other data from anchor to host a new Cloud Anchor.

A Cloud Anchor is assigned an identifier that can be used to create an GARAnchor in the same position in subsequent sessions across devices using resolveCloudAnchorWithIdentifier:completionHandler:error: (GARSession(CloudAnchors)). See the Cloud Anchors developer guide for more information.

The duration that a Cloud Anchor can be resolved for is specified by TTLDays. When using Token authorization, the maximum allowed value is 365 days. When using an API Key to authenticate with the ARCore API, the maximum allowed value is 1 day.

This launches an asynchronous operation used to query the Google Cloud ARCore API. See GARFuture for information on obtaining results and cancelling the operation.

Cloud Anchors requires a GARSessionConfiguration with GARCloudAnchorModeEnabled set on this session. Use GARSessionConfiguration.cloudAnchorMode to set the Cloud Anchor API mode and setConfiguration:error: to configure the session.

Hosting a Cloud Anchor works best when ARCore is able to create a good feature map around the ARAnchor. Use estimateFeatureMapQualityForHosting:error: (GARSession(CloudAnchors)) to determine the quality of visual features seen by ARCore in the preceding few seconds. Cloud Anchors hosted using higher quality features will generally result in quicker and more accurately resolved Cloud Anchor transforms.

ARCore can have up to 40 simultaneous Cloud Anchor operations, including resolved anchors and active hosting operations.

Details
Parameters	anchor The ARAnchor with the desired transform to be used to create a hosted Cloud Anchor. TTLDays The lifetime of the anchor in days. Must be positive. completionHandler The completion block to execute on the Main thread when the operation is complete, unless the operation is cancelled. error Out parameter for an NSError. Possible errors: GARSessionErrorCodeInvalidArgument - invalid (nil) anchor or invalid TTL. GARSessionErrorCodeNotTracking - bad current ARTrackingState. GARSessionErrorCodeResourceExhausted - tried to create too many Cloud Anchors. GARSessionErrorCodeIllegalState - current GARCloudAnchorMode is disabled.
Returns	A handle to the async operation that can be polled or cancelled.

Provided by category GARSession(CloudAnchors).

hostCloudAnchor:TTLDays:error:

- (nullable GARAnchor *)hostCloudAnchor:
(ARAnchor *)
 anchor
TTLDays:
(NSInteger) TTLDays
error:
(NSError **) error

This will create a new Cloud Anchor with a given lifetime in days, using the transform of the provided anchor.

The cloud state of the returned anchor will be set to GARCloudAnchorStateTaskInProgress and the initial transform will be set to the transform of the provided anchor. However, the returned anchor is completely independent of the original anchor, and the two transforms might diverge over time.

Hosting requires an active session for which the tracking state is ARTrackingStateNormal, as well as a working internet connection. ARCore will continue to retry silently in the background if it is unable to establish a connection to the ARCore API service.

Details
Parameters	anchor The ARAnchor with the desired transform to be used to create a hosted Cloud Anchor. TTLDays The lifetime of the anchor in days. Must be positive. The maximum allowed value is 1 if using an API Key to authenticate with the ARCore API service, otherwise the maximum allowed value is 365. error Out parameter for an NSError. Possible errors: GARSessionErrorCodeInvalidArgument - invalid (nil) anchor or invalid TTL. GARSessionErrorCodeNotTracking - bad current ARTrackingState. GARSessionErrorCodeResourceExhausted - tried to create too many Cloud Anchors. GARSessionErrorCodeIllegalState - current cloud anchor mode is disabled.
Returns	The new GARAnchor, or nil if there is an error.

Provided by category GARSession(CloudAnchors).

hostCloudAnchor:error:

- (nullable GARAnchor *)hostCloudAnchor:
(ARAnchor *)
 anchor
error:
(NSError **) error

Hosts a new Cloud Anchor based on an ARAnchor.

The new anchor will have a cloud state of GARCloudAnchorStateTaskInProgress and its initial transform will be set to that of the passed-in anchor. However, the two transforms may differ over time.

Details
Parameters	anchor The ARAnchor to host. error Out parameter for an NSError. Possible errors: GARSessionErrorCodeInvalidArgument - invalid (nil) anchor. GARSessionErrorCodeNotTracking - bad current ARTrackingState. GARSessionErrorCodeResourceExhausted - tried to create too many Cloud Anchors. GARSessionErrorCodeIllegalState - current cloud anchor mode is disabled.
Returns	The new GARAnchor, or nil if there is an error.

Provided by category GARSession(CloudAnchors).

isGeospatialModeSupported:

- (BOOL)isGeospatialModeSupported:
(GARGeospatialMode) geospatialMode

Determines whether the given geospatial mode is supported on the current device and OS version.

If this returns NO, then configuring the session with the given geospatial mode will fail with the error code GARSessionErrorCodeConfigurationNotSupported. A device may be incompatible with a given mode due to insufficient sensor capabilities.

Details
Parameters	geospatialMode The Geospatial mode.
Returns	YES if the geospatialMode is supported, NO otherwise.

Provided by category GARSession(Geospatial).

isSemanticModeSupported:

- (BOOL)isSemanticModeSupported:
(GARSemanticMode) semanticMode

Determines whether the given GARSemanticMode is supported on the current device and OS version.

If this returns NO, then using setConfiguration:error: with the given semantic mode will fail with the error code GARSessionErrorCodeConfigurationNotSupported. A device may be incompatible with a given mode due to insufficient sensor capabilities or compute performance.

Details
Parameters	semanticMode The Scene Semantics mode.
Returns	YES if the semanticMode is supported, NO otherwise.

Provided by category GARSession(Semantics).

raycastStreetscapeGeometry:direction:error:

- (nullable NSArray< GARStreetscapeGeometryRaycastResult * > *)raycastStreetscapeGeometry:
(simd_float3) origin
direction:
(simd_float3) direction
error:
(NSError **) error

Performs a raycast against Streetscape Geometry loaded by the scene.

The raycast result contains the transform of the hit as well as the GARStreetscapeGeometry that was hit.

Requires both GARSessionConfiguration.streetscapeGeometryMode to be set to GARStreetscapeGeometryModeEnabled and for GARSessionConfiguration.geospatialMode to be set to GARGeospatialModeEnabled.

Details
Parameters	origin World space origin of the ray. direction World space direction of the ray. error Out param for an NSError. Possible error codes: GARSessionErrorCodeIllegalState - current geospatial mode is disabled, or Streetscape Geometry mode is disabled, or earth has trackingState GARTrackingStateStopped. GARSessionErrorCodeNotTracking - Earth, Session, or the geometry's tracking state is not GARTrackingStateTracking.
Returns	The list of raycast hits, or nil if there was an error.

Provided by category GARSession(Geospatial).

removeAnchor:

- (void)removeAnchor:
(GARAnchor *) anchor

Removes an anchor from the session.

Details
Parameters	anchor The anchor to remove.

resolveCloudAnchorWithIdentifier:completionHandler:error:

- (nullable GARResolveCloudAnchorFuture *)resolveCloudAnchorWithIdentifier:
(NSString *) ide
ntifier
completionHandler:
(void(^)(GARAnchor *_Nullable anchor,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   GARCloudAnchorState cloudState)) completionHandler
error:
(NSError **) error

Attempts to resolve a Cloud Anchor using the provided identifier.

The Cloud Anchor must previously have been hosted by hostCloudAnchor:TTLDays:completionHandler:error: (GARSession(CloudAnchors)) or another Cloud Anchor hosting method within the allotted TTLDays. See the Cloud Anchors developer guide for more information.

This launches an asynchronous operation used to query the Google Cloud ARCore API. See GARFuture for information on obtaining results and cancelling the operation.

When resolving a Cloud Anchor, the ARCore API periodically compares visual features from the scene against the anchor's 3D feature map to pinpoint the user's position and orientation relative to the anchor. When it finds a match, the task completes.

Cloud Anchors requires a GARSessionConfiguration with GARCloudAnchorModeEnabled set on this session. Use GARSessionConfiguration.cloudAnchorMode to set the Cloud Anchor API mode and setConfiguration:error: to configure the session.

ARCore can have up to 40 simultaneous Cloud Anchor operations, including resolved anchors and active hosting operations.

Details
Parameters	identifier The Cloud Anchor identifier for the anchor. completionHandler Completion handler to be invoked on the Main thread, if not nil. error Out parameter for an NSError. Possible errors: GARSessionErrorCodeInvalidArgument - invalid (nil or empty) identifier. GARSessionErrorCodeResourceExhausted - tried to create too many Cloud Anchors. GARSessionErrorCodeIllegalState - current GARCloudAnchorMode is disabled.
Returns	A handle to the async operation that can be polled or cancelled.

Provided by category GARSession(CloudAnchors).

resolveCloudAnchorWithIdentifier:error:

- (nullable GARAnchor *)resolveCloudAnchorWithIdentifier:
(NSString *) ide
ntifier
error:
(NSError **) error

Resolves a Cloud Anchor with a given identifier.

The new anchor is immediately added to the session and returned, but without a valid transform. You don’t need to wait for a call to resolve a Cloud Anchor to complete before initiating another call. A session can be resolving up to 40 Cloud Anchors at a given time. If resolving fails, the anchor will be automatically removed from the session.

Details
Parameters	identifier The Cloud Anchor identifier for the anchor. error Out parameter for an NSError. Possible errors: GARSessionErrorCodeInvalidArgument - invalid (nil or empty) identifier. GARSessionErrorCodeResourceExhausted - tried to create too many Cloud Anchors. GARSessionErrorCodeIllegalState - current cloud anchor mode is disabled.
Returns	The new GARAnchor, or nil if there is an error.

Provided by category GARSession(CloudAnchors).

setAuthToken:

- (void)setAuthToken:
(NSString *) authToken

Provide an auth token to use when authenticating with Google Cloud Services.

If the session was created with an API Key, the token will be ignored and an error will be logged. Otherwise, the most recent valid auth token passed in will be used. Call this method each time you refresh your token.

Details
Parameters	authToken Token to use when authenticating with Google Cloud Services. This must be a nonempty ASCII string with no spaces or control characters. This will be used until another token is passed in. See documentation for supported token types.

setConfiguration:error:

- (void)setConfiguration:
(GARSessionConfiguration *) configuration
error:
(NSError **) error

Sets the configuration for the session.

Details
Parameters	configuration The new configuration to use. error Out param for an NSError.

transformFromGeospatialCoordinate:altitude:eastUpSouthQTarget:error:

- (matrix_float4x4)transformFromGeospatialCoordinate:
(CLLocationCoordinate2D) coordinate
altitude:
(CLLocationDistance) altitude
eastUpSouthQTarget:
(simd_quatf) eastUpSouthQTarget
error:
(NSError **) error

Converts the provided Earth specified horizontal position, altitude and rotation with respect to an east-up-south coordinate frame to a local transform in world coordinate space.

Details
Parameters	coordinate The latitude and longitude associated with the location, specified using the WGS84 reference frame. This must not be within .1° of the North or South pole (i.e. +- 90°). altitude Altitude in reference to the WGS 84 ellipsoid, in meters. Positive values indicate altitudes above approximate sea level. Negative values indicate altitudes below approximate sea level. eastUpSouthQTarget Represents the quaternion from the target to East-Up-South (EUS) coordinates (i.e., +X points East, +Y points up, and +Z points South). error Out param for an NSError. Possible error codes: GARSessionErrorCodeIllegalState - current Geospatial mode is disabled or earth has trackingState GARTrackingStateStopped. GARSessionErrorCodeNotTracking - Earth's or Session's ARTrackingState is not GARTrackingStateTracking. GARSessionErrorCodeInvalidArgument - latitude is not within range.
Returns	a local transform in world coordinate space.

Provided by category GARSession(Geospatial).

update:error:

- (nullable GARFrame *)update:
(ARFrame *
) frame
error:
(NSError **) error

Updates the GARSession with an ARFrame.

Call this method with every ARFrame to keep the sessions synced. Can be called on any thread. Normally, this should be called from your ARSessionDelegate's session:didUpdateFrame: method.

Details
Parameters	frame The next ARFrame from ARKit. error Out parameter for NSError. Possible errors: GARSessionErrorCodeInvalidArgument - invalid (nil) frame. GARSessionErrorCodeFrameOutOfOrder - frame has a smaller timestamp than previous.
Returns	The GARFrame corresponding to the ARFrame passed in, or nil if there is an error.