SwiftUI –将数据从SwiftUIView传递到SceneKit [英] SwiftUI – Passing data from SwiftUIView to SceneKit

问题描述

目标: 使用Scenekit(UIViewRepresentable)控制SwiftUI视图的SwiftUI切换按钮

Goal: SwiftUI toggle button that controls a SwiftUI View with Scenekit (UIViewRepresentable)

//显示诸如fps和定时信息之类的统计信息

// show statistics such as fps and timing information

我做了什么: 这是UIViewRepresentable ScenekitView

What I did: This is the UIViewRepresentable ScenekitView

import SwiftUI
import SceneKit

struct ScenekitView : UIViewRepresentable {
    let scene = SCNScene(named: "art.scnassets/ship.scn")!

    func makeUIView(context: Context) -> SCNView {
        // create and add a camera to the scene
        let cameraNode = SCNNode()
        cameraNode.camera = SCNCamera()
        scene.rootNode.addChildNode(cameraNode)

        // place the camera
        cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)

        // create and add a light to the scene
        let lightNode = SCNNode()
        lightNode.light = SCNLight()
        lightNode.light!.type = .omni
        lightNode.position = SCNVector3(x: 0, y: 10, z: 10)
        scene.rootNode.addChildNode(lightNode)

        // create and add an ambient light to the scene
        let ambientLightNode = SCNNode()
        ambientLightNode.light = SCNLight()
        ambientLightNode.light!.type = .ambient
        ambientLightNode.light!.color = UIColor.darkGray
        scene.rootNode.addChildNode(ambientLightNode)

        // retrieve the ship node
        let ship = scene.rootNode.childNode(withName: "ship", recursively: true)!

        // animate the 3d object
        ship.runAction(SCNAction.repeatForever(SCNAction.rotateBy(x: 0, y: 2, z: 0, duration: 1)))

        // retrieve the SCNView
        let scnView = SCNView()
        return scnView
    }

    func updateUIView(_ scnView: SCNView, context: Context) {
        scnView.scene = scene

        // allows the user to manipulate the camera
        scnView.allowsCameraControl = true

        // show statistics such as fps and timing information

        scnView.showsStatistics = true

        // configure the view
        scnView.backgroundColor = UIColor.black

 }

}
struct ScenekitView_Previews: PreviewProvider {
    static var previews: some View {
        ScenekitView()
    }
}

这是控制Scenekit的菜单

This is the Menu to control Scenekit

import SwiftUI


struct Menu: View {

 @State var showstats = false


    var body: some View {

        HStack {

        Form {
            Toggle(isOn:) {
               Text("Stats")
            }
        }
        .frame(width: 200.0)

            Spacer()
    }
  }
 }
struct Menu_Previews: PreviewProvider {
    static var previews: some View {
        Menu()
    }
}

这是Main Scene，在Scenekit顶部有Menu:

And this is Main Scene, with Menu on top of Scenekit:

import SwiftUI

struct MainView: View {
    var body: some View {

        ZStack {
        ScenekitView()
        Menu()
        }


    }
}

问题:如何将数据从ScenekitView传递到菜单，以便可以切换和显示/隐藏统计信息?

Question: How can I pass data from ScenekitView to Menu, so I can toggle and show/hide stats?

我尝试了ObservableObject，但无法使其正常工作.还调查了其他SO线程，但没有一个对我有用.

I tried ObservableObject but could not make it work. Also looked into other SO threads, but none worked for me.

非常感谢您的帮助！

为所有人欢呼

推荐答案

已更新: 2020年3月11日 .

Updated: March 11, 2020.

要将数据传递到 updateNSView(_:context:) 或 updateUIView(_:context:) 实例方法，您需要创建@State和@Binding属性.

使用以下代码来查找操作方法:

我已经为macOS编写了此代码，但是您可以为iOS轻松更改它:

I've written this code for macOS but you can easily change it for iOS:

import SwiftUI
import SceneKit

struct ContentView: View {

    @State var stats: Bool = true

    var body: some View {
        HStack {
            ScenekitView(showStats: $stats)
            VStack {
                Button(action: {
                    self.stats.toggle()
                }, label: {
                    Text(self.stats ? "ON" : "OFF")
                })
            }
            .frame(width: 150.0)
        }
    }
}

struct ScenekitView: NSViewRepresentable {

    @Binding var showStats: Bool
    let sceneView = SCNView(frame: .zero)
    let scene = SCNScene(named: "art.scnassets/ship.scn")!

    func scnScene(stat: Bool, context: Context) -> SCNView {
        sceneView.scene = scene
        sceneView.showsStatistics = stat
        return sceneView
    }

    func makeNSView(context: Context) -> SCNView {
        scnScene(stat: true, context: context)
    }

    func updateNSView(_ uiView: SCNView, context: Context) {
        uiView.allowsCameraControl = true
        uiView.backgroundColor = NSColor.black
        uiView.showsStatistics = showStats        
    }
}

此外，您可以在此协调器中使用Coordinator对象和delegate，以使用control属性切换对象并在renderer()方法内以60 fps更新任何内容.(例如).

Additionally you can use Coordinator object and delegate to this coordinator for switching objects using control property and for updating anything at 60 fps inside renderer() method (for example).

在这种情况下，您无需使用updateNSView()或updateUIView()方法:

In this case you do not need to use updateNSView() or updateUIView() method:

struct ScenekitView: NSViewRepresentable {

    @Binding var showStats: Bool
    let sceneView = SCNView(frame: .zero)
    let scene = SCNScene(named: "art.scnassets/ship.scn")!

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    final class Coordinator: NSObject, SCNSceneRendererDelegate {
        var control: ScenekitView

        init(_ control: ScenekitView) {
            self.control = control
        }

        func renderer(_ renderer: SCNSceneRenderer,
               updateAtTime time: TimeInterval) {

            control.sceneView.showsStatistics = control.showStats

            for i in 0...255 {
                control.sceneView.backgroundColor = NSColor(
                                  red: CGFloat(arc4random_uniform(UInt32(i))),
                                green: CGFloat(arc4random_uniform(UInt32(i))),
                                 blue: CGFloat(arc4random_uniform(UInt32(i))),
                                alpha: 1.0)
            }
        }
    }

    func scnScene(stat: Bool, context: Context) -> SCNView {
        sceneView.scene = scene
        sceneView.showsStatistics = stat
        sceneView.delegate = context.coordinator
        return sceneView
    }

    func makeNSView(context: Context) -> SCNView {
        scnScene(stat: true, context: context)
    }

    func updateNSView(_ uiView: SCNView, context: Context) { }
}

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