Wikitude SDK API Reference

API Docs for: 7.1.0
Show:

InstantTracker Class

Extends ARchitectObject
Module: AR

An InstantTracker represents the instant tracking algorithm. It does not require any pre-existing target information, but can immediately start tracking. Minimally it can be instantiated without any parameters.

Trackers can be enabled and disabled. Only one Tracker can be active at a time. The current enabled/disabled state of a Tracker is reflected in the enabled property. Should there be multiple Trackers used in the ARchitect file, the following logic applies to specify the currently active Tracker:

  • When a new Tracker is created, it is automatically set to the active one, unless it was created with enabled set to false.
  • When a specific Tracker is enabled, it is automatically set to the active one. The previously active Tracker is disabled by the system.
In case a Tracker is disabled by the system, the developer will be notified via the onDisabled trigger.

Instant tracking minimal example:

this.tracker = new AR.InstantTracker();

Instant tracking example:

this.tracker = new AR.InstantTracker({
    onChangedState:  function onChangedStateFn(state) {
        // react to a change in tracking state here
    },
    // device height needs to be as accurate as possible to have an accurate scale
    // returned by the Wikitude SDK
    deviceHeight: 1.0,

 // The initial orientation at which the instant tracking plane should be displayed in degrees.
 // Default value is AR.CONST.INITIAL_INSTANT_TRACKING_PLANE_ORIENTATION.HORIZONTAL (0°).
    trackingPlaneOrientation: 45.0
});

Constructor

InstantTracker

(
  • options
)

Parameters:

  • options Object optional

    Setup-Parameters to customize additional object properties.

    Accepted options-properties are

Methods

destroy

()

Inherited from ARchitectObject

Destroys the object.

Properties

destroyed

Boolean

Inherited from ARchitectObject

Indicates if the object has already been destroyed.

deviceHeight

Number

The device height used in the scale estimation of the instant tracking algorithm in meters.

enabled

Boolean

The current activity state of the Tracker. This property might by changed automatically by the system, in case another Tracker is enabled, causing this Tracker to be disabled. The onDisabled trigger will be called in this case.

state

Number

The current internal state of the Tracker. Can either be AR.InstantTrackerState.INITIALIZING or AR.InstantTrackerState.TRACKING.

trackingPlaneOrientation

Number

The initial orientation at which the instant tracking plane should be displayed in degrees.

Default values is AR.CONST.INITIAL_INSTANT_TRACKING_PLANE_ORIENTATION.HORIZONTAL (0°)

Events

onChangedState

The trigger fires when the Tracker changes its internal state.

The trigger is null by default, and will thus result in no action executed when the trigger fires. A developer can add custom functionality by assigning a custom function to onChangedState.

onDisabled

The trigger fires when the Tracker has been disabled by the system. It does not fire when enabled is set to false manually.

The trigger is null by default, and will thus result in no action executed when the trigger fires. A developer can add custom functionality by assigning a custom function to onDisabled.

onError

The trigger fires when the Tracker could not be instantiated by the engine.

The trigger is null by default, and will thus result in no action executed when the trigger fires. A developer can add custom functionality by assigning a custom function to onError.