SpriteKit遊戲開發 Challenge 2: An invincible zombie 問題的另一種解決方案

SpriteKit遊戲開發 Challenge 2: An invincible zombie 問題的另一種解決方案

該挑戰的目的是殭屍碰到敵人時,將其設定為無敵模式,具體要求如下:

1 You should create a variable property to track whether or not the zombie is invincible.
2 If the zombie is invincible, you shouldn’t bother enumerating the scene’s cat ladies.
3 If the zombie collides with a cat lady, don’t remove the cat lady from the scene. Instead, set the zombie as invincible. Next, run a sequence of actions that first makes the zombie blink 10 times over three seconds, then runs the block of code described below.
4 Theblockofcodeshouldsethiddentofalseonthezombie,makingsurehe’s visible at the end no matter what, and set the zombie as no longer invincible.

書上的實現如下:

func zombieHitEnemy(enemy: SKSpriteNode) {    enemy.removeFromParent()    runAction(enemyCollisionSound)    invincible = true    let blinkTimes = 10.0    let duration = 3.0    let blinkAction = SKAction.customActionWithDuration(duration) { node, elapsedTime in      let slice = duration / blinkTimes      let remainder = Double(elapsedTime) % slice      node.hidden = remainder > slice / 2    }    let setHidden = SKAction.runBlock() {      self.zombie.hidden = false      self.invincible = false    }    zombie.runAction(SKAction.sequence([blinkAction, setHidden]))  }func checkCollisions(){        if invincible {      return    }    var hitEnemies: [SKSpriteNode] = []    enumerateChildNodesWithName("enemy") { node, _ in      let enemy = node as! SKSpriteNode      if CGRectIntersectsRect(        CGRectInset(node.frame, 20, 20), self.zombie.frame) {        hitEnemies.append(enemy)      }    }    for enemy in hitEnemies {      zombieHitEnemy(enemy)    }}

我覺得有幾點可以完善的地方:

每次都需要建立blinkAction,有點浪費.可以使用共用Action 殭屍變為無敵後,如果敵人出現夠快還是會刪除其他敵人

我把blinkAction設定為lazy的計算屬性,然後直接在情境子節點枚舉中處理與敵人的碰撞,然後直接跳出遍曆,這可以保證只會刪除第一個碰撞的敵人:

lazy var blinkAction:SKAction = {        let blinkTimes = 10.0        let duration = 3.0        let blinkAction = SKAction.customActionWithDuration(duration){node,elapsedTime in            let slice = duration/blinkTimes            let remainder = Double(elapsedTime) % slice            node.hidden = remainder > slice / 2        }        return blinkAction    }()func checkCollisions(){        if zombieInvincible{            return        }        var hitEnemies:[SKSpriteNode] = []        enumerateChildNodesWithName("enemy"){node,stop in            let enemy = node as! SKSpriteNode            if CGRectIntersectsRect(CGRectInset(enemy.frame, 20, 20), self.zombie.frame){                hitEnemies.append(enemy)                self.zombieInvincible = true                let seq = SKAction.sequence([self.blinkAction,SKAction.runBlock(){                        self.zombie.hidden = false                        self.zombieInvincible = false                    }])                self.zombie.runAction(seq)                stop.memory = true            }        }        for enemy in hitEnemies{            zombieHitEnemy(enemy)        }    }