Question

寻找一种每隔30秒在屏幕中心生成一个新精灵的方法。它必须受到重力的影响。

我已设法生成精灵，但在尝试将affectedByGravity设置为true时，游戏崩溃了。

＆＃34;致命错误：在展开可选值时意外发现nil＆＃34;

这是我得到的代码：

  self.timer = NSTimer.scheduledTimerWithTimeInterval(2.0, target: self, selector: "spawningCars", userInfo: nil, repeats: true)

func spawningCars() {

    let enemyTowardsTexture = SKTexture(imageNamed: "player")
    let enemyTowards = SKSpriteNode(texture: enemyTowardsTexture)
    enemyTowards.position = ourCamera.position
    enemyTowards.physicsBody!.affectedByGravity = true
    self.addChild(enemyTowards)

    print("spawning car right")
    timer.invalidate()
    resetTimer()

}


    func resetTimer() {

        self.timer = NSTimer.scheduledTimerWithTimeInterval(5.0, target: self, selector: "spawningCars", userInfo: nil, repeats: true)
    }

Answer 1

你需要在调用sprite之前为它创建一个物理体：

enemyTowards.physicsBody = SKPhysicsBody(texture: enemyTowardsTexture, size: enemyTowardsTexture.size())

Swift 2：每30秒产生一个新的精灵

1 个答案: