在运行时使用AVCaptureDevice创建SCNMaterial会挂3秒？

Question

我正在尝试使用AVCaptureDevice创建具有SCNMaterialProperty的SCNNode。但是，当我在运行时执行此操作时，该应用程序将随机挂起3到5秒钟？兄弟有没有尝试过这些？以及如何解决？

@IBAction func tapBack(_ sender: Any) {


        if let cam = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back){

            let scene = SCNScene()

            let box = SCNBox(width: 1.0, height: 1.0, length: 1.0, chamferRadius: 0)
            box.materials.first?.diffuse.contents = cam
            let boxNode = SCNNode(geometry: box)

            let cameraNode = SCNNode()
            cameraNode.camera = SCNCamera()
            cameraNode.position = SCNVector3(0, 0, 10)


            scene.rootNode.addChildNode(boxNode)
            scene.rootNode.addChildNode(cameraNode)

            SCNTransaction.begin()
            self.sceneView.scene = scene
            SCNTransaction.commit()
        }

    }