ios - 从侧面生成敌人

Question

我正在开发我的游戏，但是当我尝试从说我只能从场景的顶部和底部生成敌人时我遇到了一个问题，我不知道为什么

这是我的计时器:

override func didMoveToView(view: SKView) {
    initialzeGame()
    NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("spawnEnemy"), userInfo: nil, repeats: true)
}

剩下的就是:

func randomBetweenNumbers(firstNum: CGFloat, secondNum: CGFloat) -> CGFloat {
    return CGFloat(arc4random()) / CGFloat(UINT32_MAX) * abs(firstNum + secondNum) + min(firstNum, secondNum)
}

func spawnEnemy() {
    //supposed to pick random point within the screen width

    let Pos = randomBetweenNumbers(0, secondNum: frame.height )
    //let PosTwo = randomBetweenNumbers(0, secondNum: frame.height )

    let enemy = SKSpriteNode(imageNamed: "zombie") //create a new enemy each time
    enemy.position = CGPointMake(CGFloat(Pos), self.frame.size.width/16)
    enemy.physicsBody = SKPhysicsBody(circleOfRadius: 7)
    enemy.physicsBody?.affectedByGravity = true
    enemy.physicsBody?.categoryBitMask = 0
    enemy.physicsBody?.contactTestBitMask = 1
    enemy.size = CGSize(width: 80, height: 70)
    let enmyact = SKAction.moveTo(hero.position, duration: 2)
    enemy.runAction(enmyact)
    addChild(enemy)
}

Answer 1

反转CGPointMake中的参数。

  enemy.position = CGPointMake(self.frame.size.width/16, CGFloat(Pos))