如何使RealityKit仅显示CollisionComponents？

Question

我正在尝试在我的ARView上看到CollisionComponents。

我在调试选项中使用了.showPhysics，但是由于屏幕上有20个对象，所以所有法线都发了疯，并且CollisionComponents的颜色不清楚（某种奇怪的粉红色）。

没有人知道如何仅将CollisionComponents呈现为.showPhysics的一部分而没有任何额外数据吗？

Answer 1

您可以通过使用简单的Swift扩展来扩展RealityKit的ARView的标准功能：

import RealityKit
import ARKit

fileprivate extension ARView.DebugOptions {

    func showCollisions() -> ModelEntity {

        print("Code for visualizing collision objects goes here...")

        let vc = ViewController()

        let box = MeshResource.generateBox(size: 0.04)    
        let color = UIColor(white: 1.0, alpha: 0.15)    
        let colliderMaterial = UnlitMaterial(color: color)

        vc.visualCollider = ModelEntity(mesh: box,
                                   materials: [colliderMaterial])    
        return vc.visualCollider
    }
}

...，然后在点击屏幕时在ViewController中调用此方法：

class ViewController: UIViewController {

    @IBOutlet var arView: ARView!

    let anchor = AnchorEntity()
    var ballEntity = ModelEntity()
    var visualCollider = ModelEntity()
    var sphere: MeshResource?

    @IBAction func onTap(_ sender: UITapGestureRecognizer) {

        sphere = MeshResource.generateSphere(radius: 0.02)

        let material = SimpleMaterial(color: .systemPink,
                                 isMetallic: false)

        ballEntity = ModelEntity(mesh: sphere!,
                            materials: [material])

        let point: CGPoint = sender.location(in: arView)

        guard let query = arView.makeRaycastQuery(from: point,
                                              allowing: .estimatedPlane,
                                             alignment: .any)
        else { return }

        let result = arView.session.raycast(query)

        guard let raycastResult = result.first
        else { return }

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

        let showCollisions = arView.debugOptions.showCollisions()
        ballEntity.addChild(showCollisions)

        ballEntity.generateCollisionShapes(recursive: true)
    }
}