subtraction wall

ViewController.swift

//
//  ViewController.swift
//  SubtractionWall
//
//  Created by MizushimaYusuke on 8/18/15.
//  Copyright (c) 2015 MizushimaYusuke. All rights reserved.
//

import UIKit
import SpriteKit

class ViewController: UIViewController {

    weak var scene : SKScene?
    var cars = Array<SKNode>()
    var walls = Array<SKNode>()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setupScene()
        createBoxes()
        createGoal()
        
        // label 
        let question = "8 - 3 = ?"
        let qLabel = SKLabelNode(text: question)
        qLabel.fontSize = 60
        qLabel.position = CGPoint(x: CGRectGetMidX(view.bounds), y: 140)
        scene?.addChild(qLabel)
    }

    func setupScene() {
        let sv = SKView(frame: view.bounds)
        let s = SKScene(size: sv.frame.size)
        s.backgroundColor = UIColor(hue: 0.25, saturation: 0.3, brightness: 0.7, alpha: 1)
        sv.presentScene(s)
        view.addSubview(sv)
        
        s.physicsWorld.gravity = CGVector(dx: 0, dy: 0)
        
        scene = s
    }
    
    func createBoxes() {
        
        func makeBox(p:CGPoint, name:String) -> SKNode {
            let box = SKSpriteNode(color: UIColor(white: 0.9, alpha: 1), size: CGSize(width: 30, height: 30))
            box.name = name
            box.position = p
            self.scene?.addChild(box)
            return box
        }
        
        for i in 0...9 {
            cars.append(makeBox(CGPoint(x: 70, y: i * 40 + 230), "car box"))
            walls.append(makeBox(CGPoint(x: CGRectGetMidX(self.view.bounds), y: CGFloat(i) * 40 + 230), "wall box"))
        }
    }
    
    func createGoal() {
        let goal = SKCropNode()
        goal.maskNode = SKSpriteNode(color: UIColor.whiteColor(), size: CGSize(width: 60, height: 390))
        goal.position = CGPoint(x: CGRectGetMaxX(view.bounds) - 70, y: 210 + 40 * 5)
        scene?.addChild(goal)
        
        goal.addChild(SKSpriteNode(color: UIColor.whiteColor(), size: CGSize(width: 60, height: 390)))
        for i in 0..<20 {
            let tile = SKSpriteNode(color: UIColor(white: 0.7, alpha: 1), size: CGSize(width: 30, height: 20))
            tile.position = CGPoint(x: (i%2 == 0) ? -15 : 15, y: 190 - 20 * i)
            goal.addChild(tile)
        }
    }
    
    func showCars(box : SKNode) {
        var show = true
        for (i, b) in enumerate(cars) {
            b.removeAllChildren()
            if show {
                let car = SKSpriteNode(color: UIColor(hue: CGFloat(i) * 0.1, saturation: 1, brightness: 0.8, alpha: 1), size: CGSize(width: 30, height: 20))
                car.name = "touch disabled"
                b.addChild(car)
            }
            if b == box { show = false }
        }
    }
    
    func showWall(box: SKNode) {
        var show = true
        for (i, b) in enumerate(walls) {
            b.removeAllChildren()
            if show {
                let wall = SKSpriteNode(color: UIColor.brownColor(), size: CGSize(width: 10, height: 30))
                wall.name = "touch disabled"
                b.addChild(wall)
            }
            if b == box { show = false }
        }
    }
    
    func start() {
        cars
            .filter {($0 as SKNode).children.count > 0}
            .map { n -> SKNode in
                return n.children.first as! SKNode
            }
            .each {n in
                n.position = n.parent!.position
                n.removeFromParent()
                self.scene?.addChild(n)
                n.physicsBody = SKPhysicsBody(rectangleOfSize: n.frame.size)
                n.physicsBody?.linearDamping = 1.0
                n.physicsBody?.restitution = 0
                n.physicsBody?.applyImpulse(CGVector(dx: 6.5, dy: 0))
            }
        walls
            .filter {($0 as SKNode).children.count > 0}
            .map { n -> SKNode in
                return n.children.first as! SKNode
            }
            .each {n in
                n.position = n.parent!.position
                n.removeFromParent()
                self.scene?.addChild(n)
                n.physicsBody = SKPhysicsBody(rectangleOfSize: n.frame.size)
                n.physicsBody?.restitution = 0
                n.physicsBody?.dynamic = false
        }
        
    
    }

    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        if let touch = touches.first as? UITouch {
            let p = touch.locationInNode(self.scene)
            var hit = scene?.nodeAtPoint(p)
            if hit!.name == "touch disabled" { hit = hit!.parent }
            if let name = hit?.name {
                if name.hasPrefix("car box") { self.showCars(hit!) }
                else if name.hasPrefix("wall box") { self.showWall(hit!) }
            } else { start() }
        }
    }
}

extension Array {
    func each(doit:T -> Void) {for i in self {doit(i)}}
}