SceneKit Tips

Zoom

func pinchWithGestureRecognizer(recognizer:UIPinchGestureRecognizer) {
  if lockCamera { return }
  SCNTransaction.begin()
  SCNTransaction.setAnimationTimingFunction(CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut))
  var fov = defaultFov
  var constraintFactor:CGFloat = 0
  if (recognizer.state == UIGestureRecognizerState.Ended || recognizer.state == UIGestureRecognizerState.Cancelled) {
    SCNTransaction.setAnimationDuration(0.5)
  }  else {
    SCNTransaction.setAnimationDuration(0.1)
    var scale:Float = Float(recognizer.scale)
    if scale < 0.4 { scale = 0.4 }
    scale = 1.0 + (Float(scale - 1) * 0.75)
    let zoom = 1.0 / scale
    fov *= Double(zoom)
    constraintFactor = min(1,(CGFloat(scale) - 1) * 0.75)
  }
  self.pointOfView!.camera!.xFov = fov
  if let constraints = self.pointOfView!.constraints {
    constraints[0].influenceFactor = constraintFactor
  }
  SCNTransaction.commit()
}