Tracker Events in Unity

Level: Intermediate

In Unity, you can listen to several events that are emitted by VisionLib to react to them.

List of available events

Event	Parameters	Description
TrackingManager.OnTrackerInitializing		Event which will be emitted once after calling the StartTracking function.
TrackingManager.OnTrackerInitialized		Event which will be emitted after the tracking configuration was loaded.
TrackingManager.OnTrackerRunning		Event which will be emitted once after the tracking was stopped or paused and is now running again.
TrackingManager.OnTrackerPaused		Event which will be emitted after the tracking was paused.
TrackingManager.OnTrackerStopped		Event which will be emitted after the tracking was stopped or the initialization of the tracker has failed.
TrackingManager.OnTrackingStates	TrackingState state	Event with the current tracking state of all tracked objects. This event will be emitted for each tracking frame. See also Tracking States in Unity.
TrackingManager.OnPerformanceInfo	PerformanceInfo state	Event with the current tracking performance. This Event will be emitted for each tracking frame.
TrackingManager.OnIssueTriggered	VLIssue issue	Event which will be emitted if an Issue was triggered.

Using Unity Events in the Inspector

The VisionLib SDK for Unity provides two components that help to react on certain events by registering to them through the Inspector without the need to write a custom script:

• The TrackerEventProvider component lets you react to OnTrackerInitialized and OnTrackerStopped
• The TrackingAnchor component lets you react to tracking state changes (Tracked, Tracking Critical, Tracking Lost) of the given object, see Tracking States in Unity

Register to Events in code

To react to VisionLib events in your own MonoBehaviour script, register to them like seen below:

using Visometry.VisionLib.SDK.Core;
 
...
 
void OnEnable() 
{
    TrackingManager.OnTrackerInitialized += HandleTrackingInitialized; 
}
 
void OnDisable() 
{
    TrackingManager.OnTrackerInitialized -= HandleTrackingInitialized; 
}
 
private void HandleTrackingInitialized() 
{
    // do something
}