在嵌入Spritekit场景的Scenekit场景中使用SCNLookAtConstraint

Question

我有一个spritekit场景，其中嵌入了一个小Scenekit场景。 即使我在相机上添加了SCNLookAtConstraint，它似乎也不指向盒子的中央。然后，每次单击时，我都会在x-z平面中将摄像机绕一个圆圈移动，因此我希望看到立方体在旋转，但是它会离开屏幕。有人知道我可能做错了吗？

代码如下：

import SpriteKit
import GameplayKit

class GameScene: SKScene {
    var clicks: Int = 0
    var cubeNodes = SCNNode()
    var cameraNode = SCNNode()
    var node = SK3DNode()
    override func didMove(to view: SKView) {
        let backgroundSquare = SKShapeNode(rectOf: CGSize(width: 400, height: 400))
        backgroundSquare.position = CGPoint(x: 0, y: 0)
        backgroundSquare.fillColor = UIColor.black
        backgroundSquare.zPosition = 1
        self.addChild(backgroundSquare)
        let scnScene: SCNScene = SCNScene()
        let cubeGeometrys = SCNBox(width: 2, height: 2, length: 2, chamferRadius: 0.0)
        cubeGeometrys.name = "cubesG"
        cubeGeometrys.firstMaterial?.diffuse.contents = UIColor.red
        cubeNodes = SCNNode(geometry: cubeGeometrys)
        cubeNodes.position = SCNVector3(0, 0, 0)
        cubeNodes.name = "cubesN"
        scnScene.rootNode.addChildNode(cubeNodes)
        node = SK3DNode(viewportSize: CGSize(width: 400, height: 400))
        node.scnScene = scnScene
        node.position = CGPoint(x: 0, y: 0)
        node.name = "3dnode"
        let camera = SCNCamera()
        let cameraNode = SCNNode()
        cameraNode.camera = camera
        node.pointOfView = cameraNode
        let constraint = SCNLookAtConstraint(target: cubeNodes)
        constraint.isGimbalLockEnabled = true
        node.pointOfView?.constraints = [ constraint ]
        node.pointOfView?.position = SCNVector3(x: 5*sin(0), y: 1, z: 5*cos(0))
        node.zPosition = 2
        self.addChild(node)
    }
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        node.pointOfView?.position.x = 5*sin(Float(clicks)/4)
        node.pointOfView?.position.z = 5*cos(Float(clicks)/4)
        clicks = clicks + 1
    }
}