Hey,

Here's some code that will let you embed a SpriteKit SKScene in a SwiftUI view hierarchy.

Let's start off with a sample scene:

import SpriteKit

class GameScene: SKScene {
    override func didMove(to view: SKView) {
        backgroundColor = .darkGray
        physicsBody = SKPhysicsBody(edgeLoopFrom: frame)
    }

    override func mouseDown(with event: NSEvent) {
        let location = event.location(in: self)

        let size = CGSize(width: 40, height: 40)
        let cube = SKShapeNode(rectOf: size)
        cube.fillColor = .red
        cube.physicsBody = SKPhysicsBody(rectangleOf: size)
        cube.position = location

        addChild(cube)
    }
}

Here are the views that will allow you to use it in SwiftUI pre-Big-Sur:

struct GameView: View {
    let scene: SKScene

    var body: some View {
        GeometryReader { proxy in
            GameViewRepresentable(scene: scene, proxy: proxy)
        }
    }
}

struct GameViewRepresentable: NSViewRepresentable {
    let scene: SKScene
    let proxy: GeometryProxy

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

    func makeNSView(context: Context) -> SKView {
        scene.size = proxy.size
        context.coordinator.scene = scene

        let view = SKView()
        view.presentScene(scene)
        return view
    }

    func updateNSView(_ nsView: SKView, context: Context) {
        context.coordinator.resizeScene(proxy: proxy)
    }

    class Coordinator: NSObject {
        weak var scene: SKScene?

        func resizeScene(proxy: GeometryProxy) {
            scene?.size = proxy.size
        }
    }
}

These will size the scene properly for the view's size, and resize it when the view's size changes. You can use them by passing your SKScene to the init(scene:) initializer of GameView like this:

struct ContentView: View {
    var body: some View {
        GameView(scene: GameScene())
    }
}

Hope that helped!

--Jakub