ios - 如何将 SCNView 更改回 UIView？

Question

我正在尝试使用 Xcode 游戏示例中的代码作为 Swift Playground。该代码在 Xcode 版本中完美运行，但在 Playground 中，我收到错误:

Could not cast value of type 'UIView' (0x114debe38) to 'SCNView' (0x12521d3d0).

类的类型设置为UIViewController类型，所以我不确定为什么这仅在 Playground 上不起作用。我在应用程序和 Playground 中都有相同的文件。

我已经看过this question ，但该方法似乎已经内置了。

如果它是 SCNView，我还尝试将其转换回 UIView，并且我还尝试创建一个新 View ，将 subview 添加为 SCNView，然后将最终 View 设置为新 View 。我的尝试都没有成功。

class GameScene: UIViewController {

let finalView = UIView()

override func viewDidLoad() {
    super.viewDidLoad()

    // create a new scene
    let scene = SCNScene(named: "art.scnassets/ship.scn")!

    // create and add a camera to the scene
    let cameraNode = SCNNode()
    cameraNode.camera = SCNCamera()
    scene.rootNode.addChildNode(cameraNode)

    // place the camera
    cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)
    cameraNode.rotation = SCNVector4(0, 0, 0, 30)

    // create and add a light to the scene
    let lightNode = SCNNode()
    lightNode.light = SCNLight()
    lightNode.light!.type = .omni
    lightNode.position = SCNVector3(x: 0, y: 10, z: 10)
    scene.rootNode.addChildNode(lightNode)

    // create and add an ambient light to the scene
    let ambientLightNode = SCNNode()
    ambientLightNode.light = SCNLight()
    ambientLightNode.light!.type = .ambient
    ambientLightNode.light!.color = UIColor.darkGray
    scene.rootNode.addChildNode(ambientLightNode)

    // retrieve the shark node
    let shark = scene.rootNode.childNode(withName: "ship", recursively: true)!

    // animate the 3d object
    //shark.runAction(SCNAction.repeatForever(SCNAction.rotateBy(x: 0, y: 2, z: 0, duration: 1)))

    // retrieve the SCNView
    let scnView = self.view as! SCNView

    // set the scene to the view
    scnView.scene = scene

    // allows the user to manipulate the camera
    scnView.allowsCameraControl = true

    // show statistics such as fps and timing information
    scnView.showsStatistics = true

    // configure the view
    scnView.backgroundColor = UIColor.black

    // add a tap gesture recognizer
    let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(_:)))
    scnView.addGestureRecognizer(tapGesture)
}

@objc
func handleTap(_ gestureRecognize: UIGestureRecognizer) {
    // retrieve the SCNView
    let scnView = self.view as! SCNView

    finalView.addSubview(scnView)

    // check what nodes are tapped
    let p = gestureRecognize.location(in: scnView)
    let hitResults = scnView.hitTest(p, options: [:])
    // check that we clicked on at least one object
    if hitResults.count > 0 {
        // retrieved the first clicked object
        let result = hitResults[0]

        // get its material
        let material = result.node.geometry!.firstMaterial!

        // highlight it
        SCNTransaction.begin()
        SCNTransaction.animationDuration = 0.5

        // on completion - unhighlight
        SCNTransaction.completionBlock = {
            SCNTransaction.begin()
            SCNTransaction.animationDuration = 0.5

            material.emission.contents = UIColor.black

            SCNTransaction.commit()
        }

        material.emission.contents = UIColor.red

        SCNTransaction.commit()
    }

}

override var shouldAutorotate: Bool {
    return true
}

override var prefersStatusBarHidden: Bool {
    return true
}

override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
    if UIDevice.current.userInterfaceIdiom == .pad {
        return .allButUpsideDown
    } else {
        return .all
    }
}
}

PlaygroundSupport.PlaygroundPage.current.liveView = GameScene()

这应该显示一个 3D 模型和一个可以通过移动设备上的触摸来平移它的相机。

Answer 1

在您的示例中，UIViewController View 可能在界面生成器中设置为 SCNView。如果您不使用 Nib ，您可以通过重写 loadView 来完成此操作。

  override func loadView() {
    let scnView = SCNView(frame: UIScreen.main.bounds, options: nil)
    self.view = scnView
  }