GARSession(CloudAnchors)

Category adding Cloud Anchor functionality to GARSession.

Summary

Public methods
`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.
`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`.
`resolveCloudAnchorWithIdentifier:error:`	`nullable GARAnchor *` Resolves a Cloud Anchor with a given identifier.

Public methods

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.

Extends class GARSession.

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.

Extends class GARSession.

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.

Extends class GARSession.

resolveCloudAnchorWithIdentifier:error:

- (nullable GARAnchor *)resolveCloudAnchorWithIdentifier:
(NSString *) identifier
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.

Extends class GARSession.