如何使SceneView的背景透明？

Question

我想打开一个3D模型并使其背景透明，这样我就可以看到SceneView后面的UI。我试过这个代码，但是sceneView变成白色，而不是透明的。

struct ModelView: View {
    var body: some View {
        ZStack {
            Text("Behind Text Behind Text Behind Text")
            SceneView(
                scene: { () -> SCNScene in
                    let scene = SCNScene()
                    scene.background.contents = UIColor.clear
                    return scene
                }(),
                pointOfView: { () -> SCNNode in
                    let cameraNode = SCNNode()
                    cameraNode.camera = SCNCamera()
                    cameraNode.position = SCNVector3(x: 0, y: 0, z: 10)
                    return cameraNode
                }(),
                options: [
                    .allowsCameraControl,
                    .temporalAntialiasingEnabled,
                ]
            )
        }
    }
}

我使用XCode 12.5和IPhone 8。

编辑1：

感谢下面的评论，我决定尝试新的方法，但它们仍然不起作用。

方法#1

首先，我尝试通过UIViewRepresentable使用SCNView创建一个MySceneView：

struct MySceneView: UIViewRepresentable {
    typealias UIViewType = SCNView
    typealias Context = UIViewRepresentableContext<MySceneView>

    func updateUIView(_ uiView: UIViewType, context: Context) {}
    func makeUIView(context: Context) -> UIViewType {
        let view = SCNView()
        view.allowsCameraControl = true
        view.isTemporalAntialiasingEnabled = true
        view.autoenablesDefaultLighting = true
        view.scene = MySceneView.scene
        return view
    }
    
    static let scene: SCNScene = {
        let scene = SCNScene(named: "art.scnassets/man.obj")!
        scene.background.contents = UIColor.clear
        let cameraNode = SCNNode()
        cameraNode.camera = SCNCamera()
        cameraNode.position = SCNVector3(x: 0, y: 0, z: 10)
        scene.rootNode.addChildNode(cameraNode)
        return scene
    }()
}

方法#2我尝试使用SpriteView，下面是代码：

        ZStack {
            Text("Behind Text Behind Text Behind Text")
            SpriteView(scene: { () -> SKScene in
                let scene = SKScene()
                scene.backgroundColor = UIColor.clear
                let model = SK3DNode(viewportSize: .init(width: 200, height: 200))
                model.scnScene = MySceneView.scene
                scene.addChild(model)
                return scene
            }(), options: [.allowsTransparency])
}

Answer 1

更新：

更简单的解决方案是使用UIViewRepresentable，创建SCNView并将backgroundColor设置为clear

旧的：

谢谢George_E，你和SpriteKit的想法工作得很好。代码如下：

SpriteView(scene: { () -> SKScene in
    let scene = SKScene()
    scene.backgroundColor = UIColor.clear
    let model = SK3DNode(viewportSize: .init(width: 200, height: 200))
    model.scnScene = {
        let scene = SCNScene(named: "art.scnassets/man.obj")!
        scene.background.contents = UIColor.clear
        let cameraNode = SCNNode()
        cameraNode.camera = SCNCamera()
        cameraNode.position = SCNVector3(x: 0, y: 0, z: 10)
        scene.rootNode.addChildNode(cameraNode)
        return scene
    }()
    scene.addChild(model)
    return scene
}(), options: [.allowsTransparency])