I have a class that contains an ARSCNView:

class ARSessionCameraView: NSObject {

    var delegate: ARViewWrapperDelegate?
    var arKitView: ARSCNView = ARSCNView()

    // Sets the frame of the ARKit view
    func setupViews(arFrame: CGRect) {
        arKitView = ARSCNView(frame: arFrame)
        self.delegate?.viewsDidCreate(arKitView: arKitView)
    }

    // Sets the session delegate
    func setupARSession(position: AVCaptureDevice.Position) {
        if position == .back {
            let configuration = ARWorldTrackingConfiguration()
            configuration.planeDetection = [.horizontal]
            configuration.userFaceTrackingEnabled = true
            self.arKitView.session.run(configuration)
        } else if position == .front {
            let configuration = ARFaceTrackingConfiguration()
            configuration.isWorldTrackingEnabled = true
            self.arKitView.session.run(configuration)
        }
        self.arKitView.session.delegate = self
   ...
}

I'm able to receive delegate update calls from ARSessionDelegate:

extension ARSessionCameraView: ARSessionDelegate {
    // Called whenever there is a new ARFrame from the ARSession
    func session(_ session: ARSession, didUpdate frame: ARFrame) {
    }

    func session(_ session: ARSession, cameraDidChangeTrackingState camera: ARCamera) {
        print(camera.trackingState)
    }

    func sessionWasInterrupted(_ session: ARSession) {
        // Inform the user that the session has been interrupted, for example, by presenting an overlay.
    }
}

But, for some reason can't receive delegate updates from these ARSCNViewDelegate methods:

extension ARSessionCameraView: ARSCNViewDelegate {

    /// - Tag: PlaceARContent
    func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
        // Place content only for anchors found by plane detection.
        guard let planeAnchor = anchor as? ARPlaneAnchor else { return }

    }

    /// - Tag: UpdateARContent
    func renderer(_ renderer: SCNSceneRenderer, didUpdate node: SCNNode, for anchor: ARAnchor) {
        // Update only anchors and nodes set up by `renderer(_:didAdd:for:)`.
        guard let planeAnchor = anchor as? ARPlaneAnchor
        else { return }

    }

}

CodePudding user response：

You never set the delegate property on your ARSCNView instance.

func setupViews(arFrame: CGRect) {
    arKitView = ARSCNView(frame: arFrame)
    arKitView.delegate = self // Add this line
    self.delegate?.viewsDidCreate(arKitView: arKitView)
}

And you most likely also need to add arKitView to a parent view in order for those delegate methods to be called.