在RealityKit中是否可以为对象提供基于位置的锚点？

如何解决在RealityKit中是否可以为对象提供基于位置的锚点？

我创建了一个运行良好的AR应用程序，但我并不是每次都在镜头前产生的物体的拥护者。我宁愿让它们在此区域中生成，并朝相机更远的方向并面向预定方向。例如，我希望每次都有一辆汽车在相同的停车场内产生，所以当我走进停车场时，无论我从哪个方向走，都可以看到那辆车停在那儿就像我离开了车。 / p>

如何根据对象的位置生成对象？我认为这与用纬度和经度坐标替换平面检测有关，但是我不知道该怎么做。 任何帮助将不胜感激！

import UIKit
import RealityKit
import ARKit

class ViewController: UIViewController {

@IBOutlet var arView: ARView!

override func viewDidLoad() {
    super.viewDidLoad()
 
    arView.session.delegate = self
    
    showModel()
    overlayCoachingView()
    setupARView()
    
    arView.addGestureRecognizer(UITapGestureRecognizer(target: self,action: #selector(handleTap(recognizer:))))
    
}

func showModel(){
    
    let anchorEntity = AnchorEntity(plane: .horizontal,minimumBounds:[0.2,0.2])
    
    let entity = try! Entity.loadModel(named: "COW_ANIMATIONS")
    entity.setParent(anchorEntity)
    
    arView.scene.addAnchor(anchorEntity)
    
}
func overlayCoachingView () {
    
    let coachingView = ARCoachingOverlayView(frame: CGRect(x: 0,y: 0,width: arView.frame.width,height: arView.frame.height))
    
    coachingView.session = arView.session
    coachingView.activatesAutomatically = true
    coachingView.goal = .horizontalPlane
    
    view.addSubview(coachingView)
    
}
    
    // Load the "Box" scene from the "Experience" Reality File
   // let boxAnchor = try! Experience.loadBox()
    
    // Add the box anchor to the scene
    //arView.scene.anchors.append(boxAnchor)

func setupARView(){
    arView.automaticallyConfigureSession = false
    let configuration = ARWorldTrackingConfiguration()
    configuration.planeDetection = [.horizontal,.vertical]
    configuration.environmentTexturing = .automatic
    arView.session.run(configuration)
}

//object placement

@objc
func handleTap(recognizer: UITapGestureRecognizer){
    let location = recognizer.location(in:arView)
    
    let results = arView.raycast(from: location,allowing: .estimatedPlane,alignment: .horizontal)
    
    if let firstResult = results.first {
        let anchor = ARAnchor(name: "COW_ANIMATIONS",transform: firstResult.worldTransform)
        arView.session.add(anchor: anchor)
    } else {
        print("Object placement failed - couldn't find surface.")
    }
}

func placeObject(named entityName: String,for anchor: ARAnchor)  {
    let entity = try! ModelEntity.loadModel(named: entityName)
    
    entity.generateCollisionShapes(recursive: true)
    arView.installGestures([.rotation,.translation],for: entity)
    
    
    let anchorEntity = AnchorEntity(anchor: anchor)
    anchorEntity.addChild(entity)
    arView.scene.addAnchor(anchorEntity)
    
    
  }
 }
 extension ViewController: ARSessionDelegate {
  func session( session: ARSession,didAdd anchors: [ARAnchor]) {
  for anchor in anchors {
    if let anchorName = anchor.name,anchorName == "COW_ANIMATIONS" {
        placeObject(named: anchorName,for: anchor)
    }  }
}
}

解决方法

对于地理位置，Apple制作了ARGeoTrackingConfiguration和相应的ARGeoAnchors。

let location = CLLocationCoordinate2D(latitude: -18.9137,longitude: 47.5361)
let geoAnchor = ARGeoAnchor(name: "Tana",coordinate: location,altitude: 1250)
arView.session.add(anchor: geoAnchor)
let realityKitAnchor = AnchorEntity(anchor: geoAnchor)
arView.scene.anchors.append(realityKitAnchor)

目前它正在current cities and areas中工作。

您还可以使用getGeoLocation(forPoint:completionHandler:)实例方法，将框架的本地坐标系中的位置转换为GPS纬度，经度和海拔高度。

arView.session.getGeoLocation(forPoint: xyzWorld) { (coord,alt,error) in
    let anchor = ARGeoAnchor(coordinate: coord,altitude: alt)
}