将 3D 对象添加到 ARGeoAnchor

如果这个问题不太好，请原谅我。我在 Apple 的 ARGeoAnchor 文档中遇到了一些障碍。

目前，ARGeoAnchor 仅在 AR 场景视图中显示一个蓝点。我正在尝试显示任何 3D 渲染或对象。

My code:

let coordinate = CLLocationCoordinate2D(latitude: lat, longitude: lng)
let geoAnchor = ARGeoAnchor(name: "Point 1", coordinate: coordinate)
    
let boxGeometry = SCNBox(width: 0.1, height: 0.1, length: 0.1, chamferRadius: 0)
let cube = SCNNode(geometry: boxGeometry)
geoAnchor.scene.rootNode.addChildNode(cube)
self.addGeoAnchor(geoAnchor)

我收到的错误：Value of type 'ARGeoAnchor' has no member 'scene'

我有多个 ARGeoAnchor，它们当前都显示蓝点。我如何让它们显示自定义 3D 对象？

谢谢参观！

首先你必须检查是否ARGeoTrackingConfiguration您的设备支持。

要求：您需要配备 A12+ 芯片并支持蜂窝 (GPS) 的设备。

import ARKit

@main class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, 
                       didFinishLaunchingWithOptions launchOptions: 
                                      [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        if !ARGeoTrackingConfiguration.isSupported {

            let sb = UIStoryboard(name: "Main", bundle: nil)

            window?.rootViewController = sb.instantiateViewController(withIdentifier:
                                                             "unsupportedConfiguration")
        }
        return true
    }
}

...然后检查您所在位置是否可以使用地理跟踪：

ARGeoTrackingConfiguration.checkAvailability { (available, error) in

    if !available {
        let errorDescription = error?.localizedDescription ?? ""
        let recommendation = "You need a place where geo tracking is supported."
        let restart = UIAlertAction(title: "Restart", style: .default) { (_) in
            self.restartSession()
        }
        self.alertUser(withTitle: "Geo tracking unavailable",
                         message: "\(errorDescription)\n\(recommendation)",
                         actions: [restart])
    }
}

供应之后Info.plist with camera and 位置权限。这里有一个全面的信息定位服务授权请求 https://developer.apple.com/documentation/corelocation/requesting_authorization_for_location_services包括：

• NSLocationWhenInUseUsageDescription
• NSLocationAlwaysAndWhenInUseUsageDescription
• NSLocationUsageDescription
• NSLocationAlwaysUsageDescription

目前仅支持美国、英国、澳大利亚、加拿大、日本和新加坡的几个城市......

支持 ARGeoTrackingConfiguration 的城市列表 https://developer.apple.com/documentation/arkit/argeotrackingconfiguration.

然后您必须运行地理配置：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    
    let config = ARGeoTrackingConfiguration()
    sceneView.session.run(config)
}

然后将参数化锚点添加到会话中：

@IBOutlet var sceneView: ARSCNView!

override func viewDidLoad() {
    super.viewDidLoad()
    sceneView.delegate = self
    sceneView.scene = SCNScene()
    
    let coordinate = CLLocationCoordinate2D(latitude: 40.730610, 
                                           longitude: -73.935242)

    let geoAnchor = ARGeoAnchor(name: "Geo Anchor",
                          coordinate: coordinate,
                            altitude: 33.0)
    
    sceneView.session.add(anchor: geoAnchor)
}

之后，您可以在 ARGeoAnchor 的帮助下添加模型：

extension ViewController: ARSCNViewDelegate {
    
    func renderer(_ renderer: SCNSceneRenderer,
                 didAdd node: SCNNode,
                  for anchor: ARAnchor) {
            
        guard let geoAnchor = anchor as? ARGeoAnchor,
                  geoAnchor.name == "Geo Anchor"
        else { return }
        
        print(geoAnchor.coordinate)
                
        let boxGeometry = SCNBox(width: 1.0,
                                height: 1.0,
                                length: 1.0,
                         chamferRadius: 0.1)

        boxGeometry.firstMaterial?.diffuse.contents = UIColor.red

        let cube = SCNNode(geometry: boxGeometry)
        
        node.addChildNode(cube)
    }
}

P.S.

如果您对 ARCore 中类似功能的工作原理感兴趣，请阅读我的文章地理空间API https://stackoverflow.com/questions/50382855/arcore-and-sceneform-with-geolocation/72213814#72213814.