CollisionEvent没有在RealityKit场景中开火的原因？

Question

事件订阅已添加到ARView的ARView的RealityKit中。

arView.scene.subscribe(to: CollisionEvents.Began.self) { event in
    print("Some collision occured")
}

Entities在scene中视觉上发生了碰撞，但是CollisionEvent没有被触发。下面是两个明显冲突的对象的示例层次结构：

__RKPhysics▿‘篮板’，孩子们:1

...⟐PhysicsMotionComponent

...⟐变换

...⟐CollisionComponent

...⟐SynchronizationComponent

...⟐PhysicsBodyComponent

...▿'simpBld_root‘：ModelEntity

......⟐变换

......⟐ModelComponent

......⟐SynchronizationComponent

用CollisionComponent

CollisionComponent(形状: RealityKit.ShapeResource，模式: RealityKit.CollisionComponent.Mode.default，过滤器:RealityKit.CollisionFilter(组: RealityKit.CollisionGroup(rawValue: 1)，掩码: RealityKit.CollisionGroup(rawValue: 1)

ModelEntity ...⟐变换▿'ball‘

...⟐CollisionComponent

...⟐ModelComponent

...⟐SynchronizationComponent

...⟐PhysicsBodyComponent

用CollisionComponent

CollisionComponent(形状: RealityKit.ShapeResource，模式: RealityKit.CollisionComponent.Mode.default，过滤器:RealityKit.CollisionFilter(组: RealityKit.CollisionGroup(rawValue: 1)，掩码: RealityKit.CollisionGroup(rawValue: 4294967295)

已将名为Entities的内容作为AnchorEntity的一部分添加到

let anchorEntity = AnchorEntity(anchor: anchor)
anchorEntity.addChild(backboardEntity)
anchorEntity.addChild(ballEntity)
arView.scene.anchors.append(anchorEntity)

为什么没有CollisionEvents不被解雇？

Answer 1

此代码不言自明：

import RealityKit
import Combine

class ViewController: UIViewController {
    
    @IBOutlet var arView: ARView!
    var subscriptions: [Cancellable] = []
    
    override func viewDidLoad() {
        super.viewDidLoad()            
        let modelOne = ModelEntity(mesh: .generateSphere(radius: 0.04)) 
                               as (Entity & HasCollision & HasPhysicsBody)
        let modelTwo = ModelEntity(mesh: .generateSphere(radius: 0.04)) 
                               as (Entity & HasCollision & HasPhysicsBody)
        
        modelOne.position.y = 0.75
        modelOne.physicsBody = .init()
        modelOne.physicsBody?.mode = .dynamic
        modelOne.generateCollisionShapes(recursive: false)            
        modelTwo.physicsBody = .init()
        modelTwo.physicsBody?.mode = .static
        modelTwo.generateCollisionShapes(recursive: false)
        
        let sub = arView.scene.subscribe(to: CollisionEvents.Began.self, 
                                on: modelOne) { _ in print("OCCURED!") }
        subscriptions.append(sub)
        
        let anchor = AnchorEntity()
        anchor.addChild(modelOne)
        anchor.addChild(modelTwo)
        arView.scene.anchors.append(anchor)
    }
}