在同步非隔离上下文中调用主参与者隔离实例方法

Question

我正在 Swift 中开发一个 ARKit 项目，我试图接收 AR 锚点并在 AR 场景中每个检测到的锚点处放置一个小球体。我有一个符合 ARSessionDelegate 的 AppModel 类，它管理 AR 会话和场景内容。

我收到以下错误：

Call to main actor-isolated instance method ‘createSphereEntity(radius:)’ in a synchronous nonisolated context

如何解决？

import Foundation
import RealityAR
import SwiftUI
import ARKit
import RealityKit

@MainActor
@Observable
class AppModel: NSObject, ARSessionDelegate {
    
    let session = ARSession()
//    let sceneRecostruction = SceneReconstructionProvider()
//    let handTracking = HandTrackingProvider()
    
    var arView: ARView!
    var objectInScene = Entity()
    
    override init() {
        super.init()
        setupARView()
    }
    
    func setupARView() {
        // Initialize the ARView
        arView = ARView(frame: .zero)
        arView.session.delegate = self  // Set ARSessionDelegate
        
        // Create AR session configuration
        let configuration = ARWorldTrackingConfiguration()
        configuration.planeDetection = [.horizontal, .vertical]
        
        // Enable scene reconstruction if needed
        if ARWorldTrackingConfiguration.supportsSceneReconstruction(.mesh) {
            configuration.sceneReconstruction = .mesh
        }
        
        // Run AR session
        arView.session.run(configuration)
        print("Session running")
    }
    
    func loadModel() async {
        // Add the initial RealityKit content
        if let person = try? await Entity(named: "person", in: realityARBundle) {
            let radians = 180.0 * Float.pi / 180.0
            person.transform.rotation = simd_quatf(angle: radians,axis: SIMD3<Float>(0,1,0))
            person.scale = SIMD3(0.5, 0.5, 0.5)
            person.components.set(GroundingShadowComponent(castsShadow: true))
            let anchor = AnchorEntity(.plane(.horizontal, classification: .table, minimumBounds: SIMD2(0.5, 0.5)))
            anchor.addChild(person)
            arView.scene.addAnchor(anchor)
        } else {
            print("Couldn't load the character")
        }
    }
   
    // Helper function to create a sphere entity
    func createSphereEntity(radius: Float) -> ModelEntity {
        let mesh = MeshResource.generateSphere(radius: radius)
        let material = SimpleMaterial(color: .blue, isMetallic: false)
        return ModelEntity(mesh: mesh, materials: [material])
    }
    
    nonisolated func session(_ session: ARSession, didAdd anchors: [ARAnchor]) {
        let spere = createSphereEntity(radius: 0.1) // <------ error here 
        
    }
    
}

Answer 1

您的调用位于显式标记为

nonisolated

的函数内部，但该函数与主线程隔离，因此您必须异步调用它。

    
nonisolated func session(_ session: ARSession, didAdd anchors: [ARAnchor]) async {
        let spere = await createSphereEntity(radius: 0.1)
}