SpriteKit-Coordinate-Conversion

Coordinate-Conversion.swift

import SpriteKit
import SwiftUI
import Combine



enum ControlUpdate {
    case tap(UITapGestureRecognizer) // print SpriteKit coordinate
    case doubleTap // reset camera
    case pan(UIPanGestureRecognizer) // move camera
    
}

struct ExampleView: View {
    @State var isPaused = false
    
    var messages = PassthroughSubject<ControlUpdate, Never>()

    var body: some View {
        GeometryReader { geo in
            SpriteKitView(isPaused: $isPaused,
                   size: geo.size,
                   messages: messages)
            .overlay(gestures)
        }
    }
    
    @ViewBuilder var gestures: some View {
        ExampleGestureRepresentable(messages: messages)
            .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}

struct SpriteKitView: View {
    @Binding var isPaused: Bool

    let size: CGSize
    let messages:  PassthroughSubject<ControlUpdate, Never>

    var scene: SKScene{
        let scene = ExampleScene(size: size,
                                 messages: messages)
        scene.size = size
        scene.scaleMode = .fill
        return scene
    }

    var body: some View {
        SpriteView(scene: scene,
                   isPaused: isPaused)
                    .frame(width: size.width, height: size.height)
    }
}

struct ExampleGestureRepresentable: UIViewRepresentable {
    let messages:  PassthroughSubject<ControlUpdate, Never>
    
    func makeUIView(context: Context) -> some UIView {
        let v = UIView(frame: .zero)
        
        let tap = UITapGestureRecognizer(target: context.coordinator, action: #selector(Coordinator.tap))
        v.addGestureRecognizer(tap)

        let pan = UIPanGestureRecognizer(target: context.coordinator, action: #selector(Coordinator.pan))
        v.addGestureRecognizer(pan)
        
        let doubleTap = UITapGestureRecognizer(target: context.coordinator, action: #selector(Coordinator.doubleTap))
        doubleTap.numberOfTapsRequired = 2
        v.addGestureRecognizer(doubleTap)

        return v
    }
    
    class Coordinator: NSObject, UIGestureRecognizerDelegate {
        let messages:  PassthroughSubject<ControlUpdate, Never>

        init(messages: PassthroughSubject<ControlUpdate, Never>) {
            self.messages = messages
        }
        
        @objc func tap(gesture: UITapGestureRecognizer) {
            messages.send(.tap(gesture))
        }
         
        @objc func doubleTap(gesture: UITapGestureRecognizer) {
            messages.send(.doubleTap)
        }
        
        
        @objc func pan(gesture: UIPanGestureRecognizer) {
            messages.send(.pan(gesture))
        }
    }
    
    func makeCoordinator() -> Coordinator {
        Coordinator(messages: messages)
    }
    
    func updateUIView(_ uiView: UIViewType, context: Context) {}
}

class ExampleScene: SKScene {
    let messages:  PassthroughSubject<ControlUpdate, Never>
    
    init(size: CGSize,
         messages: PassthroughSubject<ControlUpdate, Never>) {
        self.messages = messages
        
        super.init(size: size)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func sceneDidLoad() {
        super.sceneDidLoad()
        setup()
    }
    
    var cancellables = Set<AnyCancellable>()
    
    private func  setup() {
        messages
            .sink(receiveValue: handle)
            .store(in: &cancellables)
        
        // setup nodes

        let shape: CGPath = .init(roundedRect: .init(origin: .zero,
                                                     size: .init(width: 50,height: 50)),
                                  cornerWidth: 12,
                                  cornerHeight: 12,
                                  transform: nil)
                        
        
        
        let tapNode = SKShapeNode(path: shape, centered: true)
        self.shapeNode = tapNode
        self.shapeNode?.position = origin
        self.shapeNode?.fillColor = .blue
        addChild(tapNode)

        let node = SKShapeNode(path: shape, centered: true)
        node.position = origin
        node.fillColor = .orange
        addChild(node)

        
        camera = sceneCamera
        sceneCamera.position = origin
        addChild(sceneCamera)
    }
    
    var sceneCamera: SKCameraNode = SKCameraNode()
    var shapeNode: SKShapeNode? = nil
    
    var origin: CGPoint {
        CGPoint(x: size.width / 2.0, y: size.height / 2.0)
    }
    
    var dragOrigin: CGPoint = .zero

    private func handle(_ message: ControlUpdate) {
        switch message {
        case .tap(let gesture):
            let location = gesture.location(in: gesture.view)
            let point = convertPoint(fromView: location)
            
            moveNode(node: shapeNode,
                     to: point,
                     at: 0.3,
                     with: .easeOut)
            
        case .pan(let  pan):
            switch pan.state {
            case .began:
                dragOrigin = self.camera?.position ?? .zero
            case .changed:
                let translation = pan.translation(in: pan.view)
                let point =  CGPoint(x: dragOrigin.x - translation.x,
                                     y: dragOrigin.y + translation.y)
                
                moveNode(node: sceneCamera,
                         to: point)
            case .ended, .cancelled:
                dragOrigin = .zero
                
            default: break
            }
            break
            
        case .doubleTap:
            moveNode(node: sceneCamera,
                     to: origin,
                     at: 0.3,
                     with: .easeInEaseOut)
            break
        }
    }
    
    func moveNode(node: SKNode?,
                  to point: CGPoint,
                    at  duration: CGFloat = 0.0,
                    with timing: SKActionTimingMode = .linear) {
        let move = SKAction.move(to: point, duration: duration)
        move.timingMode = timing
        
        node?.run(move, withKey: "moveNode")
    }
}

I've created an Xcode project and put the code in ContentView.swift and replaced all the ContentView with ExampleView.
The preview is running. I usually try across iPhones and iPads to make sure that the code is responsive. I want to avoid any layout or positioning that is tied to a specific screen or ratio.

Could you please elaborate on what is the code supposed to do so I can match the intent with the code?

Right now, I can:

• Drag with one or two fingers to pan the camera
• Tap anywhere to move a blue square toward the tap position
• Double tap to reset the camera position

Thank you!