节点名被USDZ模型覆盖

Question

我目前正在开发一个iOS应用程序，它使用ARKit和SceneKit来实现增强现实。在将.usdz模型加载到场景中时，我遇到了问题。我可以正确地将它加载到场景中，但是，当我尝试在点击后得到节点名称(在其中加载了.usdz模型)，它返回的是.usdz名称，而不是我给它的名称。

用于加载.usdz模型的代码是：

let mdlAsset = MDLAsset(url: urlPath)
mdlAsset.loadTextures()
let asset = mdlAsset.object(at: 0) // extract first object
var assetNode = SCNNode(mdlObject: asset)
assetNode = SCNNode(mdlObject: asset)
assetNode.name = "Node-2"
sceneView.scene.rootNode.addChildNode(assetNode)

要捕获节点上的抽头，代码是：

@objc func handleTap(recognizer: UITapGestureRecognizer){
       
    let location = recognizer.location(in: sceneView)
    let results = sceneView.hitTest(location, options: nil)

    guard recognizer.state == .ended else { return }

    if results.count > 0 {
        let result = results[0] as SCNHitTestResult
        let node = result.node  
        print(node.name)    
    }     
}

正如我前面提到的，当我点击对象时，它会打印“0")值，这个值可以在右上角的模型详细信息页中找到。我所期望的正确值是"Node-2“。

Answer 1

USDZ模型的名称不会被覆盖。这是SceneKit命中测试和场景层次结构的特点.执行命中测试搜索时，SceneKit沿着指定的射线查找SCNGeometry对象(而不是主节点)。因此，一旦命中测试完成，您所需要做的就是找到相应的父节点。

试试下面的代码：

import SceneKit.ModelIO

class GameViewController: UIViewController {
    
    var sceneView: SCNView!
        
    override func viewDidLoad() {
        super.viewDidLoad()
        
        sceneView = (self.view as! SCNView)
        let scene = SCNScene(named: "art.scnassets/ship.scn")!
        sceneView.scene = SCNScene()
        sceneView.backgroundColor = .black
        
        let recog = UITapGestureRecognizer(target: self, action: #selector(tap))
        sceneView.addGestureRecognizer(recog)
        
        // ASSET
        let mdlAsset = MDLAsset(scnScene: scene)
        let asset = mdlAsset.object(at: 0)
        let node = SCNNode(mdlObject: asset.children[0])
        node.name = "Main-Node-Name"                       // former "ship"
        node.childNodes[0].name = "SubNode-Name"           // former "shipMesh"
        node.childNodes[0].childNodes[0].name = "Geo-Name" // former "Scrap_MeshShape"
        sceneView.scene?.rootNode.addChildNode(node)
    }
}

你的命中测试方法：

extension GameViewController {
    
    @objc func tap(recognizer: UITapGestureRecognizer) {
           
        let location = recognizer.location(in: sceneView)
        let results = sceneView.hitTest(location)

        guard recognizer.state == .ended else { return }

        if results.count > 0 {
            let result = results[0] as SCNHitTestResult
            let node = result.node
            
            print(node.name!)                            // Geo-Name
            print(node.parent!.name!)                    // SubNode-Name
            print(node.parent!.parent!.name!)            // Main-Node-Name
        }
    }
}