Testing memory build up of a SpriteKit scene when it is presented again and again.

MemoryBuildUp.swift

/**
 
 # SpriteKit Memory Buildup
 
 Testing memory build up of a SpriteKit scene when it is presented again and again.
 
 Achraf Kassioui
 Created 23 November 2024
 Updated 23 November 2024
 
 */

import SwiftUI
import SpriteKit

// MARK: SwiftUI

struct MemoryBuildUpView: View {
    let myScene = MemoryBuildUpScene()
    var body: some View {
        SpriteView(
            scene: myScene,
            debugOptions: [.showsFPS, .showsNodeCount, .showsDrawCount, .showsQuadCount]
        )
        .ignoresSafeArea()
        .background(Color(SKColor.black))
        .persistentSystemOverlays(.hidden)
    }
}

#Preview {
    MemoryBuildUpView()
}

class MemoryBuildUpScene: SKScene {
    
    // MARK: Scene Setup
    
    override func didMove(to view: SKView) {
        size = view.bounds.size
        scaleMode = .resizeFill
        anchorPoint = CGPoint(x: 0.5, y: 0.5)
        backgroundColor = .gray
        view.isMultipleTouchEnabled = true
        
        createSomeNodes()
        createButton()
    }
    
    // MARK: Create Something
    
    func createSomeNodes() {
        physicsWorld.gravity = CGVector(dx: 0, dy: 0)
        self.physicsBody = SKPhysicsBody(edgeLoopFrom: self.frame)
        
        for i in 1...300 {
            let sprite = SKSpriteNode(color: .systemYellow, size: CGSize(width: 10, height: 10))
            sprite.name = "NaNCandidate"
            sprite.physicsBody = SKPhysicsBody(rectangleOf: sprite.size)
            sprite.physicsBody?.charge = -0.5
            
            run(SKAction.wait(forDuration: Double(i) * 0.01)) {
                self.addChild(sprite)
            }
        }
        
        let field = SKFieldNode.electricField()
        field.position = CGPoint(x: -1, y: -1)
        field.minimumRadius = 100
        field.strength = 1
        addChild(field)
    }
    
    // MARK: Update
    
    override func update(_ currentTime: TimeInterval) {
        /// In some extreme cases, a physics simulation would make a node disappear from the scene. Even constraints wouldn't hold it in.
        /// Logging the disappearing node position returns a NaN value.
        /// This enumeration checks if the position is NaN, and brings back the node into view.
        enumerateChildNodes(withName: "//*NaNCandidate*", using: { node, stop in
            if node.position.x.isNaN || node.position.y.isNaN {
                print("position is absurd")
                node.physicsBody?.velocity = .zero
                node.physicsBody?.angularVelocity = 0
                node.position = CGPoint(x: 100, y: 100)
            }
        })
    }
    
    // MARK: Present Scene
    
    func presentSceneAgain() {
        guard let view = self.view else { return }
        print("presentSceneAgain MemoryBuildUpScene")
        view.presentScene(MemoryBuildUpScene())
    }
    
    // MARK: Buttons
    
    func createButton() {
        let shape = SKShapeNode(rectOf: CGSize(width: 200, height: 60), cornerRadius: 12)
        shape.name = "button"
        shape.lineWidth = 2
        shape.strokeColor = SKColor(white: 0, alpha: 0.6)
        shape.fillColor = SKColor(white: 0, alpha: 0.3)
        shape.position = CGPoint(x: 0, y: -330)
        addChild(shape)
        
        let label = SKLabelNode(text: "Present Scene")
        label.fontName = "Menlo-Bold"
        label.fontSize = 18
        label.verticalAlignmentMode = .center
        label.horizontalAlignmentMode = .center
        shape.addChild(label)
    }
    
    // MARK: Touch
    
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        for touch in touches {
            print("\ntouchesBegan MemoryBuildUpScene")
            
            let touchedNodes = nodes(at: touch.location(in: self))
            if let topNode = touchedNodes.max(by: { $0.zPosition > $1.zPosition}) {
                if topNode.name == "button" || topNode.inParentHierarchy(childNode(withName: "button")!) {
                    presentSceneAgain()
                }
            }
        }
    }
}