Swift - 跳跃吃苹果游戏开发（SpriteKit游戏开发）

import SpriteKit
 
class AppleFactory:SKNode{
    //定义苹果纹理
    let appleTexture = SKTexture(imageNamed: "apple")
    //游戏场景的狂赌
    var sceneWidth :CGFloat = 0.0
    //定义苹果数组
    var arrApple = [SKSpriteNode]()
    //定时器
    var timer = NSTimer()
     
    func onInit(width:CGFloat) {
        self.sceneWidth = width
        //启动的定时器
        timer = NSTimer.scheduledTimerWithTimeInterval( 0.2, target: self,
            selector: "createApple", userInfo: nil, repeats: true)
    }
     
    //创建苹果类
    func createApple(){
        //通过随机数来随机生成苹果
        //算法是，随机生成0-9的数，当随机数大于8的时候声称苹果
        //也就是说，有1/10的几率生成苹果
        //这样游戏场景中的苹果就不会整整齐齐以相同间隔出现了
        let random = arc4random() % 10
        if random > 8 {
            //生成苹果
            let apple = SKSpriteNode(texture: appleTexture)
            //设置物理体
            apple.physicsBody = SKPhysicsBody(rectangleOfSize: apple.size)
            //弹性设为0
            apple.physicsBody?.restitution = 0
            //物理体标识
            apple.physicsBody?.categoryBitMask = BitMaskType.apple
            //不受物理效果影响
            apple.physicsBody?.dynamic = false
            //设置中心点
            apple.anchorPoint = CGPointMake(0, 0)
            //z轴深度
            apple.zPosition = 40
            //设定位置
            let theY = CGFloat(arc4random()%200 + 200)
            apple.position  = CGPointMake(sceneWidth+apple.frame.width , theY)
            //加入数组
            arrApple.append(apple)
            //加入场景
            self.addChild(apple)
        }
    }
     
    //苹果移动方法
    func move(speed:CGFloat){
        for apple in arrApple {
            apple.position.x -= speed
        }
        //移出屏幕外时移除苹果
        if arrApple.count > 0 && arrApple[0].position.x < -20{
            arrApple[0].removeFromParent()
            arrApple.removeAtIndex(0)
        }
    }
     
    //重置方法
    func reSet(){
        //移除所有子对象
        self.removeAllChildren()
        //清空苹果数组
        arrApple.removeAll(keepCapacity: false)
    }
}

import SpriteKit
 
class Panda: SKSpriteNode {
    //定义纹理
    let pandaTexture = SKTexture(imageNamed: "panda")
     
    init() {
        //执行父类的构造方法
        super.init(texture:pandaTexture,color:SKColor.whiteColor(),size:pandaTexture.size())
        //设置中心点
        self.anchorPoint = CGPointMake(0, 0)
         
        self.physicsBody = SKPhysicsBody(rectangleOfSize:pandaTexture.size())
        self.physicsBody?.dynamic = true
        self.physicsBody?.allowsRotation = false
         
        //弹性
        self.physicsBody?.restitution = 0
        self.physicsBody?.categoryBitMask = BitMaskType.panda
        self.physicsBody?.contactTestBitMask = BitMaskType.scene|BitMaskType.apple
        self.physicsBody?.collisionBitMask = BitMaskType.scene
    }
     
    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
     
    //跳
    func jump (){
        //施加一个向上的力，让小人跳起来
        self.physicsBody?.velocity = CGVectorMake(0, 700)
    }
}

class BitMaskType {
    class var panda:UInt32{
        return 1<<0
    }
    class var apple:UInt32{
        return 1<<1
    }
    class var scene:UInt32{
        return 1<<2
    }
}

import SpriteKit
 
class GameScene: SKScene,SKPhysicsContactDelegate {
    lazy var appleFactory = AppleFactory()
    lazy var panda = Panda()
     
    //移动速度
    var moveSpeed:CGFloat = 15
    //吃到的苹果数
    var appleNum = 0
     
    override func didMoveToView(view: SKView) {
        //物理世界代理
        self.physicsWorld.contactDelegate = self
        //重力设置
        self.physicsWorld.gravity = CGVectorMake(0, -5)
        //设置物理体
        self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
        //设置种类标示
        self.physicsBody?.categoryBitMask = BitMaskType.scene
        //是否响应物理效果
        self.physicsBody?.dynamic = false
         
        //场景的背景颜色
        let skyColor = SKColor(red:113/255,green:197/255,blue:207/255,alpha:1)
        self.backgroundColor = skyColor
         
        //给小人定一个初始位置
        panda.position = CGPointMake(200, 400)
        //将小人显示在场景中
        self.addChild(panda)
         
        //苹果工厂
        appleFactory.onInit(self.frame.width)
        self.addChild( appleFactory )
    }
     
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        panda.jump()
    }
    
    override func update(currentTime: CFTimeInterval) {
        appleFactory.move(moveSpeed)
    }
     
    //碰撞检测方法
    func didBeginContact(contact: SKPhysicsContact) {
        //熊猫和苹果碰撞
        if (contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask)
            == (BitMaskType.apple | BitMaskType.panda){
                //苹果计数加1
                self.appleNum++
                //如果碰撞体A是苹果，隐藏碰撞体A，反之隐藏碰撞体B
                //（因为苹果出了屏幕都会被移除，所以这里隐藏就可以了）
                if contact.bodyA.categoryBitMask == BitMaskType.apple {
                    contact.bodyA.node?.hidden = true
                }else{
                    contact.bodyB.node?.hidden = true
                }
        }
    }
}