MapViewController.swift

extension MapViewController: SensorDispatchHandler {
    
    /* 
       After initializing a WearableDeviceSession and calling sensorDispatch.handler = self in viewDidLoad(),
       Your view controllers can receive raw heading information with the receivedRotation delegate method.
       We use this information to render a custom vision cone on screen.
    */
    
    func receivedRotation(quaternion: Quaternion, accuracy: QuaternionAccuracy, timestamp: SensorTimestamp) {

        // 1. Convert raw heading data to degrees
        let qMap = Quaternion(ix: 1, iy: 0, iz: 0, r: 0)
        let qResult = quaternion * qMap
        let yaw: Double = (-qResult.zRotation).toDegrees()
        
        // 2. Get user location from the Mapbox MapView
        guard let userLocation = mapView.userLocation?.location, userLocation.horizontalAccuracy > 0 else {
            return
        }
        
        // 3. Convert degrees to magnetic degreees (0°-360°)
        let magneticDegrees: Double = (yaw < 0) ? 360 + yaw : yaw
        
        // 4. Update the direction of a custom vision cone to show user heading in the UI
        vision.updateVisionPath(center: userLocation.coordinate, orientation: 360 - magneticDegrees)
        locationManager.visionPolygon(for: userLocation.coordinate, orientation: 360 - magneticDegrees)
    }
  
}