SceneKit- 画中画效果实现方案

    let scene = SCNScene()
    
    // 创建照相机
    let cameraNode = SCNNode()
    cameraNode.camera = SCNCamera()
    cameraNode.camera?.automaticallyAdjustsZRange = true
    scene.rootNode.addChildNode(cameraNode)
    cameraNode.position = SCNVector3(x: 0, y: 10, z: 100)
    
    // 创建灯光
    let lightNode = SCNNode()
    lightNode.light = SCNLight()
    lightNode.light!.type = .omni
    lightNode.position = SCNVector3(x: 0, y: 10, z: 10)
    scene.rootNode.addChildNode(lightNode)
    
    let ambientLightNode = SCNNode()
    ambientLightNode.light = SCNLight()
    ambientLightNode.light!.type = .ambient
    ambientLightNode.light!.color = UIColor.darkGray
    scene.rootNode.addChildNode(ambientLightNode)
    
    // 设置相关属性
    let scnView = self.view as! SCNView
    scnView.scene = scene
    scnView.allowsCameraControl = true
    scnView.showsStatistics = true
    scnView.backgroundColor = UIColor.black
    
    
    // 创建一面墙
    let plane = SCNPlane(width: 50, height: 50)
    let planeNode = SCNNode(geometry: plane)
    planeNode.position = SCNVector3Make(0, 25, 0)
    scene.rootNode.addChildNode(planeNode)
    scnView.isPlaying = true
    
    
    // 创建一个地板
     let floorNode = SCNNode()
    floorNode.geometry = SCNFloor()
    floorNode.geometry?.firstMaterial?.diffuse.contents = "floor.jpg"
    scene.rootNode.addChildNode(floorNode)
    
    // 创建内画面
    let sceneShip = SCNScene(named: "art.scnassets/ship.scn")!
    let cameraNode1 = SCNNode()
    cameraNode1.camera = SCNCamera()
    sceneShip.rootNode.addChildNode(cameraNode1)
    cameraNode1.position = SCNVector3(x: 0, y: 0, z: 10)
    let ship = sceneShip.rootNode.childNode(withName: "ship", recursively: true)!
    ship.runAction(SCNAction.repeatForever(SCNAction.rotateBy(x: 0, y: 2, z: 0, duration: 1)))
    let view = SCNView(frame: CGRect(x: 0, y: 0, width: 1000, height: 1000))
    view.scene = sceneShip
    view.backgroundColor = UIColor.gray
    
    // 设置内画面视图为plane渲染的纹理
    plane.firstMaterial?.diffuse.contents = view