Subscribing to Gesture Recognition Hooks

To start recognizing gestures, drag a PrehensionManager into your scene (from the plugin’s Prefabs folder). It’ll need a reference to your PrehensionConfig (which should be in Assets/PrehensionData) and your Head transform (for Meta/Oculus, this should be CenterEyeAnchor in the Camera Rig). You can then reference the PrehensionManager in any of your other scripts, and use it to hook into gesture information. There are two main hooks/events you can subscribe to:

Gesture Recognized

public void SubscribeToGestureRecognized(OnGestureRecognized func)

// Example
public void NewGestureRecognized(string gestureName)
{
		Debug.Log($"Gesture {gestureName} was recognized!");
}

public PrehensionManager prehension;
prehension.SubscribeToGestureRecognized(NewGestureRecognized);

A function subscribed this way will be called any time the model has identified a gesture as having been performed.

New Gesture Candidate

public void SubscribeToGestureCandidate(OnGestureCandidate func)

// Example
public void NewGestureCandidate(string gestureName)
{
		Debug.Log($"Gesture {gestureName} is now a candidate gesture");
}

public PrehensionManager prehension;
prehension.SubscribeToGestureCandidate(NewGestureCandidate);

A function subscribed this way will be called whenever the model recognizes a new gesture candidate. Internally, the model outputs a ‘most likely gesture’ at every frame. When that gesture switches (say from ‘User likely doing nothing’ to ‘User likely swiping right’) a new candidate gesture is registered (in this case ‘Swipe Right’). If the model continues to say the user is likely performing that gesture, it will eventually be fully recognized and the OnGestureRecognized event will fire.

This is useful for looking back in time to when a gesture started, for example when determining what a user was pointing at with their hand before they started swiping right.

Gesture Released

public void SubscribeToGestureReleased(OnGestureReleased func)

// Example
public void OnGestureReleased(string gestureName)
{
		Debug.Log($"Gesture {gestureName} has been released");
}

public PrehensionManager prehension;
prehension.SubscribeToGestureReleased(OnGestureReleased);

A function subscribed this way will be called whenever a gesture designated in the config as ‘Fire and Hold’ (see Gesture Config Options) is released. Note that this event will not fire if the gesture isn’t marked as such.

This is useful for gestures that you expect the player to maintain for an indefinite amount of time.