MultiSetCallback

Overview

MultiSetCallback is the protocol your app implements to receive SDK events: authentication, localization, object tracking, and mesh loading. The instance is passed to MultiSet.shared.initialize(config:callback:) and is held weakly by the SDK.

class MultiSetSDKDelegate: MultiSetCallback {
    func onSDKReady() { }
    func onAuthenticationSuccess() { }
    func onAuthenticationFailure(error: String) { }
    func onLocalizationSuccess(result: LocalizationResult) { }
    func onLocalizationFailure(error: String) { }
    func onTrackingStateChanged(state: TrackingState) { }
}

Only the six methods above are required. Every other method has a default no-op implementation, so existing integrations keep compiling when new callbacks are added.

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Required Methods

onSDKReady()

Called synchronously from initialize(config:callback:), before authentication starts.

This is not an authentication signal. Wait for onAuthenticationSuccess() before calling localize(). Attaching an ARSession here is safe, because the SDK applies it once authenticated.

onAuthenticationSuccess()

Authentication with the MultiSet servers succeeded. The SDK is ready to localize.

onAuthenticationFailure(error: String)

Authentication failed.

Parameter	Type	Description
error	String	Description of the failure

onLocalizationSuccess(result: LocalizationResult)

A pose was returned and accepted. The gizmo has moved and, if meshVisualization is enabled, the mesh is loading.

Parameter	Type	Description
result	LocalizationResult	See LocalizationResult

onLocalizationFailure(error: String)

The localization request failed, or no pose was found.

Parameter	Type	Description
error	String	Description of the failure

When firstLocalizationUntilSuccess is enabled, failures before the first success are retried silently and do not reach this callback.

onTrackingStateChanged(state: TrackingState)

ARKit tracking state changed.

Parameter	Type	Description
state	TrackingState	.tracking, .paused or .stopped

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Optional Methods

Each of these has a default empty implementation.

onLocalizationFalsePositive(info: FalsePositiveInfo)

The server returned a pose, but it contradicts the device's own AR trajectory, so the SDK discarded it. This fires instead of onLocalizationSuccess, and only when poseConsistencyCheck is enabled.

The request itself succeeded. The answer was wrong, most likely because the query image matched a visually similar part of the space. The AR scene is left untouched: the gizmo and mesh keep the last accepted pose.

Parameter	Type	Description
info	FalsePositiveInfo	Details of the discarded response, see below

func onLocalizationFalsePositive(info: FalsePositiveInfo) {
    print("Discarded: \(info.summary)")

    if info.consecutiveCount >= 3 {
        // Repeated rejections from one spot usually mean the user should move,
        // or that the reference itself is stale.
        showResetPrompt()
    }
}

There is no automatic fast retry after a false positive, because a retry from the same spot tends to produce the same wrong match. Prompt the user to move to a more distinctive viewpoint and localize again. If they insist the rejections are wrong, call MultiSet.shared.resetPoseConsistencyReference(), which makes the next result trusted and adopted as the new reference.

onMeshLoaded(mapCode: String)

A map mesh finished downloading and rendering.

Parameter	Type	Description
mapCode	String	Code of the map whose mesh was loaded

onMeshLoadError(error: String)

Mesh download or rendering failed. Localization itself is unaffected.

onObjectTrackingSuccess(objectCode: String, confidence: Double)

A tracked object was located and its outline mesh placed.

Parameter	Type	Description
objectCode	String	Code of the detected object
confidence	Double	Detection confidence (0.0 to 1.0)

onObjectTrackingFailure(error: String)

Object tracking failed or no object was matched.

onObjectMeshLoaded(objectCode: String)

An object mesh was loaded and rendered with the outline shader.

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FalsePositiveInfo

Details of a localization response that the pose consistency check discarded.

Property	Type	Description
jumpMeters	Float	How far the discarded response placed the map from where the last accepted fix placed it
thresholdMeters	Float	The tolerance that was in force, from poseConsistencyThreshold
consecutiveCount	Int	Consecutive false positives since the last accepted fix. 1 on the first one
mapCodes	[String]	Map codes the server reported for the discarded response
confidence	Float?	Server confidence of the discarded response, when reported
reason	String	Short machine-readable explanation, for logs
summary	String	One-line description of all of the above, ready to log

A high confidence on a discarded response is normal and is the point of the check. The server was sure about a match that the device's own motion rules out.

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Related

• MultiSetConfig

• LocalizationResult

• LandingView

• ARLocalizationView