eye color illusion

ViewController.swift

//
//  ViewController.swift
//  EyeColorIllusion
//
//  Created by MizushimaYusuke on 8/6/15.
//  Copyright (c) 2015 MizushimaYusuke. All rights reserved.
//

//
// my blog : http://lepetit-prince.net/ios/?p=4217
//
// 参考にしたサイト： 色の恒常性 <http://www.psy.ritsumei.ac.jp/~akitaoka/colorconstancy.html>[Accessed 6 August 2015]
//

import UIKit
import SpriteKit

class ViewController: UIViewController {
    
    weak var scene : SKScene?
    weak var selected : SKSpriteNode?
    var colorA = UIColor.cyanColor()
    var colorB = UIColor.redColor()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setupScene();
        createFace();
        createCellophane();
    }
    
    func setupScene() {
        let sv = SKView(frame: view.bounds)
        let s = SKScene(size: sv.frame.size)
        s.backgroundColor = UIColor.lightGrayColor()
        sv.presentScene(s)
        view.addSubview(sv)
        
        scene = s
    }
    
    let eyeOuter = UIBezierPath(ovalInRect: CGRectMake(-30, -30, 60, 60))
    let eyeInner = UIBezierPath(arcCenter: CGPointZero, radius: 5, startAngle: 0, endAngle: CGFloat(M_PI) * 2.0, clockwise: false)
    
    func createFace() {
        let face = SKShapeNode(circleOfRadius: 120)
        face.fillColor = UIColor(white: 0.9, alpha: 1)
        face.lineWidth = 4
        face.strokeColor = UIColor.darkGrayColor()
        face.position = CGPoint(x:CGRectGetMaxX(view.bounds) * 0.75, y:CGRectGetMidY(view.bounds))
        scene?.addChild(face)
        
        for i in 0...1 {
            let eye = SKShapeNode(path: eyeOuter.CGPath)
            eye.position = CGPoint(x: i==0 ? -50 : 50, y: 10)
            eye.strokeColor = face.strokeColor
            eye.fillColor = colorA
            eye.lineWidth = face.lineWidth
            
            let black = SKShapeNode(path: eyeInner.CGPath)
            black.fillColor = UIColor.darkGrayColor()
            black.strokeColor = face.strokeColor
            eye.addChild(black)
            
            face.addChild(eye)
        }
        
        let mouth = SKSpriteNode(color: UIColor.darkGrayColor(), size: CGSize(width: 30, height: 4))
        mouth.position = CGPoint(x: 0, y: -50)
        face.addChild(mouth)
    }
    
    func createCellophane() {
        let cellophane = SKSpriteNode()
        cellophane.name = "cellophane"
        scene?.addChild(cellophane)
        
        let partA = SKSpriteNode(color: colorB.colorWithAlphaComponent(0.5), size: CGSize(width: CGRectGetMidX(view.bounds), height: CGRectGetMaxY(view.bounds)))
        partA.position = CGPoint(x: 0, y: 0)
        cellophane.addChild(partA)
        
        let path = UIBezierPath(CGPath: eyeOuter.CGPath)
        path.usesEvenOddFillRule = true
        path.appendPath(eyeInner)
        
        let partEye = SKShapeNode(path: path.CGPath)
        partEye.fillColor = colorB.colorWithAlphaComponent(0.5)
        partEye.lineWidth = 0
        partEye.position = CGPoint(x: CGRectGetMidX(view.bounds) * 0.5 + 50, y: 10);
        cellophane.addChild(partEye)
    }
    
    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        if let touch = touches.first as? UITouch {
            let p = touch.locationInNode(scene)
            let n = scene?.nodeAtPoint(p)
            if n?.parent?.name == "cellophane" {
                self.selected = n?.parent as? SKSpriteNode
                self.selected?.position = p
            }
        }
    }
    
    override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
        if let touch = touches.first as? UITouch {
            let p = touch.locationInNode(scene)
            self.selected?.position = p
        }
    }
}