ARKit & Reality composer - 如何使用图像坐标锚定场景

Question

我编写了代码来初始化 3 个 Reality Composer 场景中的一个，当按下按钮时，根据月份中的哪一天进行。

一切正常。

Reality Composer 场景使用图像检测将对象放置在环境中，但目前只要图像离开相机视图，对象就会消失。

我想将场景锚定在第一次检测到图像的根节点处，以便用户可以环顾场景，即使图像触发器不在相机视图中，也可以维护对象。

我尝试在下面传入一个 func 渲染器代码，但我收到错误消息说视图控制器类没有 .planeNode

 func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
            guard let imageAnchor = anchor as? ARImageAnchor else { return }
            let referenceImage = imageAnchor.referenceImage

                // Create a plane to visualize the initial position of the detected image.
                let plane = SCNPlane(width: referenceImage.physicalSize.width,
                                 height: referenceImage.physicalSize.height)
                plane.materials.first?.diffuse.contents = UIColor.blue.withAlphaComponent(0.20)
                self.planeNode = SCNNode(geometry: plane)

                self.planeNode?.opacity = 1

                /*
                 `SCNPlane` is vertically oriented in its local coordinate space, but
                 `ARImageAnchor` assumes the image is horizontal in its local space, so
                 rotate the plane to match.
                 */
                self.planeNode?.eulerAngles.x = -.pi / 2

                /*
                 Image anchors are not tracked after initial detection, so create an
                 animation that limits the duration for which the plane visualization appears.
                 */

                // Add the plane visualization to the scene.
                if let planeNode = self.planeNode {
                    node.addChildNode(planeNode)
                }

                if let imageName = referenceImage.name {
                    plane.materials = [SCNMaterial()]
                    plane.materials[0].diffuse.contents = UIImage(named: imageName)
                }

这是我的代码

import UIKit
import RealityKit
import ARKit
import SceneKit



class ViewController: UIViewController {



@IBOutlet var move: ARView!
    @IBOutlet var arView: ARView!

    var ARBorealAnchor3: ARboreal.ArBoreal3!

    var ARBorealAnchor2: ARboreal.ArBoreal2!

    var ARBorealAnchor: ARboreal.ArBoreal!

    var Date1 = 1




    override func viewDidLoad() {
        super.viewDidLoad()



        func getSingle() {
            let date = Date()
            let calendar = Calendar.current
            let day = calendar.component(.day, from: date)
            Date1 = day
        }

     getSingle()

      ARBorealAnchor = try! ARboreal.loadArBoreal()

        ARBorealAnchor2 = try!
        ARboreal.loadArBoreal2()

        ARBorealAnchor3 = try!
              ARboreal.loadArBoreal3()



        if Date1 == 24 {
            arView.scene.anchors.append(ARBorealAnchor)
        }
        if Date1 == 25 {
            arView.scene.anchors.append(ARBorealAnchor2)
        }
        if Date1 == 26 {
            arView.scene.anchors.append(ARBorealAnchor3)
        }
    }
}

任何帮助将不胜感激。

干杯， 丹尼尔·萨维奇

Answer 1

发生的情况是，当图像锚点离开视野时，AnchorEntity 变得未锚定，RealityKit 将停止渲染它及其所有后代。

解决此问题的一种方法可能是将您的图像锚点和您要渲染的内容分开，在代码中手动添加图像锚点，然后当第一次检测到图像锚点时，将您的内容添加到不同的场景中世界锚。当图像锚点变换更新时，更新您的世界锚点以匹配。

这样，您可以在图像锚点可见时使用它来获取最新的转换，但当它消失时，内容的渲染不会与之绑定。如下所示（您必须创建一个名为 ARTest 的 AR 资源组并向其中添加一个名为“test”的图像才能使锚点工作）：

import ARKit
import SwiftUI
import RealityKit
import Combine

struct ContentView : View {
    var body: some View {
        return ARViewContainer().edgesIgnoringSafeArea(.all)
    }
}

let arDelegate = SessionDelegate()

struct ARViewContainer: UIViewRepresentable {

  func makeUIView(context: Context) -> ARView {

    let arView = ARView(frame: .zero)

    arDelegate.set(arView: arView)
    arView.session.delegate = arDelegate

    // Create an image anchor, add it to the scene. We won't add any
    // rendering content to the anchor, it will be used only for detection
    let imageAnchor = AnchorEntity(.image(group: "ARTest", name: "test"))
    arView.scene.anchors.append(imageAnchor)

    return arView
  }

  func updateUIView(_ uiView: ARView, context: Context) {}
}

final class SessionDelegate: NSObject, ARSessionDelegate {
  var arView: ARView!
  var rootAnchor: AnchorEntity?

  func set(arView: ARView) {
    self.arView = arView
  }

  func session(_ session: ARSession, didAdd anchors: [ARAnchor]) {

    // If we already added the content to render, ignore
    if rootAnchor != nil {
       return
    }

    // Make sure we are adding to an image anchor. Assuming only
    // one image anchor in the scene for brevity.
    guard anchors[0] is ARImageAnchor else {
      return
    }

    // Create the entity to render, could load from your experience file here
    // this will render at the center of the matched image
    rootAnchor = AnchorEntity(world: [0,0,0])
    let ball = ModelEntity(
      mesh: MeshResource.generateBox(size: 0.01),
      materials: [SimpleMaterial(color: .red, isMetallic: false)]
    )
    rootAnchor!.addChild(ball)

    // Just add another model to show how it remains in the scene even
    // when the tracking image is out of view.
    let ball2 = ModelEntity(
      mesh: MeshResource.generateBox(size: 0.10),
      materials: [SimpleMaterial(color: .orange, isMetallic: false)]
    )
    ball.addChild(ball2)
    ball2.position = [0, 0, 1]

    arView.scene.addAnchor(rootAnchor!)
  }

  func session(_ session: ARSession, didUpdate anchors: [ARAnchor]) {
    guard let rootAnchor = rootAnchor else {
      return
    }

    // Code is assuming you only have one image anchor for brevity
    guard let imageAnchor = anchors[0] as? ARImageAnchor else {
      return
    }

    if !imageAnchor.isTracked {
      return
    }

    // Update our fixed anchor to image transform
    rootAnchor.transform = Transform(matrix: imageAnchor.transform)
  }

}

#if DEBUG
struct ContentView_Previews : PreviewProvider {
  static var previews: some View {
    ContentView()
  }
}
#endif

注意：当您四处走动时，ARImageAnchor 的变换似乎会频繁更新，因为 ARKit 正在尝试计算准确的图像平面（例如，内容可能看起来在正确的位置，但 z 值不准确） ，请确保您的图像尺寸在 AR 资源组中准确，以便图像获得更好的跟踪。