Question

我正在尝试创建一个场景，让不同的用户可以显示不同的汽车。当用户首次登录应用程序时，他们会获得uid，用户名等信息。当他们选择汽车时，汽车模型将具有汽车的类型以及用于识别它们的用户对象。

我可以创建一辆汽车，并实施hitTest来找出那辆被挖掘的汽车。我不知道如何为被窃听的汽车分配数据模型，以便知道谁是谁？

到目前为止，我在节点上发现的唯一属性是node.name，我可以将userId附加到该属性上，然后遍历一系列用户以找出谁是谁，但是那不是；如果我有很多用户。删除节点时，我还需要该属性：

sceneView.session.pause()
sceneView.scene.rootNode.enumerateChildNodes { (node, _) in
    // this would actually remove all the ferraries on the scene but this is just an example
    if node.name == "ferrari" {
        node.removeFromParentNode()
    }
}

如何将数据模型附加到SCNNode？

class User { var userId: String? var username: String? } class RaceCar { var user: User? var type: String? } // user creates an account and picks a ferrari let raceCar = RaceCar() let type = raceCar.type! switch type { case "ferrari": createFerrariAndAddItToScene(raceCar) case "bmw": ...etc } func createFerrariAndAddItToScene(_ raceCar: RaceCar) { let image = art.scnassests/"\(raceCar.typ!e).jpg" let material = SCNMaterial() material.diffuse.contents = image let plane = SCNPlane(width: 0.1, height: 0.1) plane.materials = [material] let node = SCNNode() node.name = raceCar.type! node.geometry = plane node.position = SCNVector(0.0, 0.0, -0.2) sceneView.scene.rootNode.addChildNode(node) } @objc func nodeWasTapped(_ sender: UITapGestureRecognizer) { guard let sceneView = sender.view as? ARSCNView else { return } let touchLocation = sender.location(in: sceneView) let hitResults = sceneView.hitTest(touchLocation, options: [:]) if !hitResults.isEmpty { guard let hitResult = hitResults.first else { return } let node = hitResult.node print(node.name) // I need to get some info from the dataModel here like node.raceCar.user.username or node.raceCar.user.userId } }

Answer 1

您可以继承SCNNode并为其添加所需的任何数据模型：

class CarNode: SCNNode {
  var raceCar: RaceCar?

  init(raceCar: RaceCar, geometry: SCNGeometry) {
    super.init()

    self.geometry = geometry

    self.raceCar = raceCar
  }

  required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }
}

要创建新节点，只需使用以下新类：

func createFerrariAndAddItToScene(_ raceCar: RaceCar) {
  ...
  let node = CarNode(raceCar: raceCar, geometry: plane)
  ...
}

要访问数据模型，您可以这样做：

@objc func nodeWasTapped(_ sender: UITapGestureRecognizer) {
  ...
  if let node = hitResult.node as? CarNode {
    print(node.raceCar.user.username)
  }
}

如何将结构或类对象附加到SCNNode

1 个答案: