swift spritekit 随着时间的推移增加节点创建的频率答案

【问题标题】：swift spritekit increase frequency of node creation as time goes onswift spritekit 随着时间的推移增加节点创建的频率
【发布时间】：2016-12-22 07:27:05
【问题描述】：

我已经弄清楚如何每 x 秒连续生成一个节点。但是，我想随着游戏的进行减少等待创建节点的时间，以增加难度。比如我在didMoveToView中调用了这个函数：

func createSequentialEnemies(){
    runAction(SKAction.repeatActionForever(
        SKAction.sequence([
            SKAction.runBlock(createEnemy),
            SKAction.waitForDuration(2.0)
            ])
        ))
}

这会每 2 秒创建一个敌人，但我想任意减少此持续时间。例如，假设在玩了 30 秒后，我想现在每 1.5 秒生成一次敌人。如何动态更改持续时间？

【问题讨论】：

标签： swift skaction

【解决方案1】：

在您的场景类中创建 spawnDuration 属性和键引用。

class SomeClass: SKScene {

       private var spawnDuration: NSTimeInterval = 2.0
       private let spawnKey = "SpawnKey"

}

调整您的生成代码以使用此生成属性和密钥。在我看来，我还稍微更改了语法以使其更易读。

func createSequentialEnemies(){
      removeActionForKey(spawnKey) // remove previous action if running. This way you can adjust the spawn duration property and call this method again and it will cancel previous action.

      let spawnAction = SKAction.runBlock(createEnemy)
      let spawnDelay = SKAction.waitForDuration(spawnDuration)
      let spawnSequence = SKAction.sequence([spawnAction, spawnDelay])
      runAction(SKAction.repeatActionForever(spawnSequence), withKey: spawnKey) // run action with key so you can cancel it later
}

您必须添加一些关于何时更改您创建的生成持续时间属性的逻辑。

基于时间的函数可以是这样的函数，您也可以在 DidMoveToView 中调用一次

 func startDifficultyTimer() {

     let difficultyTimerKey = "DifficultyTimerKey"

     let action1 = SKAction.waitForDuration(30)
     let action2 = SKAction.runBlock { [unowned self] in

          guard self.spawnDuration > 0.2 else {  // set a min limit
              removeActionForKey(difficultyTimerKey) // if min duration has been reached than you might as well stop running this timer.
              return 
          } 

          self.spawnDuration -= 0.5 // reduce by half a second
          self.createSequentialEnemies() // spawn enemies again

     }
     let sequence = SKAction.sequence([action1, action2])
     runAction(SKAction.repeatActionForever(sequence), withKey: difficultyTimerKey)
 }

希望对你有帮助

【讨论】：