FactoryMethodパターンでリファクタリングすると、ゲーム開発がどう便利になるのかをSwiftコードで学ぶ：iOS SDKとSwiftで始めるゲーム作成入門（6）（1/4 ページ）

import UIKit
import SpriteKit
 
class Button: SKSpriteNode {
    let afterTap: () -> ()
 
    init(text: String, rect: CGRect, afterTap: () -> ()) {
        self.afterTap = afterTap
        super.init(texture: nil, color: UIColor.clearColor(), size: rect.size)
        position = rect.origin
 
        let button = SKShapeNode(rect: CGRect(origin: CGPoint(), size: rect.size),
                                 cornerRadius: 4.0)
        button.fillColor = UIColor.darkGrayColor()
        button.strokeColor = UIColor.clearColor()
        addChild(button)
        let myLabel = SKLabelNode(fontNamed: "HiraginoSans-W6")
        myLabel.text = text
        myLabel.fontSize = 18
        myLabel.position = CGPoint(
            x:rect.width/2,
            y:rect.height/2-myLabel.frame.height/2+1)
        addChild(myLabel)
    }
 
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

import UIKit
import SpriteKit
 
class SetCharScene: SKScene {
    override func didMoveToView(view: SKView) {
        physicsWorld.gravity = CGVectorMake(0, 0)
        let fieldImageLength = view.frame.width / 10
        let field = FieldFactory().createField(view.frame.size, fieldImageLength: fieldImageLength)
        field.nodes.forEach {
            addChild($0)
        }
 
        let buttonRect = CGRect(x: CGRectGetMaxX(self.frame) - 115,
                                y: CGRectGetMaxY(self.frame) - 49,
                                width: 110, height: 34)
        let button = Button(text: "ゲーム開始", rect: buttonRect, afterTap: {
            let scene = GameScene(fileNamed: "GameScene")
            scene?.scaleMode = .ResizeFill
            view.presentScene(scene)
        })
        addChild(button)
    }
}

class GameViewController: UIViewController {
 
    override func viewDidLoad() {
        super.viewDidLoad()
 
        let scene = SetCharScene()
        // Configure the view.
        let skView = self.view as! SKView
        skView.showsFPS = true
        skView.showsNodeCount = true
 
        /* Sprite Kit applies additional optimizations to improve rendering performance */
        skView.ignoresSiblingOrder = true
        /* Set the scale mode to scale to fit the window */
        scene.scaleMode = .ResizeFill
 
        skView.presentScene(scene)
    }
 
    // 省略
}