玩家進入GameScene場景中 -> 通過GKStateMachine進入到指定的遊戲狀態GKState

在GameScene場景中 -> 根據不同的邏輯調用GKStateMachine -> 在各個不同的遊戲狀態GKState之間進行切換

源碼如下：

一、GameScene.swft

import SpriteKit
import GameplayKit

class GameScene: SKScene,SKPhysicsContactDelegate {
    
    //MARK: - StateMachine 場景中各個舞臺State
    lazy var stateMachine:GKStateMachine = GKStateMachine(states: [
        WaitingState(scene: self),
        PlayState(scene: self),
        GameOverState(scene: self)])

override func didMove(to view: SKView) {
 stateMachine.enter(MenuState.self) // 進入MenuState
}

   func restartGame(){
        let newScene = GameScene(fileNamed: "GameScene")!
        newScene.size = CGSize(width: SCENE_WIDTH, height: SCENE_HEIGHT)
        newScene.anchorPoint = CGPoint(x: 0, y: 0)
        newScene.scaleMode   = .aspectFill
        let transition = SKTransition.crossFade(withDuration: TimeInterval(0.5))
        view?.presentScene(newScene, transition:transition)
        //reload GameScene 直接進入遊戲狀態;
        newScene.stateMachine.enter(PlayState.self)
    }

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        guard let touch = touches.first else {
            return
        }
        // 當 physicsWorld.body(at: touchLocation)為nil時
        // 采用atPoint 取得場景中的的精靈
        let touchLocation = touch.location(in: self) ///獲得點擊的位置
        let nodeAtPoint = self.atPoint(touchLocation) //返回SKNode
        /// 判斷目前的GameScene場景舞臺是哪個state
        switch stateMachine.currentState {
        case is WaitingState:
            
            /// 判斷是否是點擊了PlayButton
            if nodeAtPoint.name == "playButton" {
                stateMachine.enter(PlayState.self)
            }
            
            if nodeAtPoint.name == "learnTemp" {
                print("weird")
                UIApplication.shared.open(URL(string: "http://www.iFIERO.com")!, options: convertToUIApplicationOpenExternalURLOptionsKeyDictionary([:]), completionHandler: { (error) in
                    print("jump to http://www.iFiero.com")
                })
            }
            
        case is PlayState:
            //挑戰：判斷是否是點擊了暫停按鈕 PauseButton
            //            if nodeAtPoint.name == "pauseButton" {
            //                stateMachine.enter(PauseState.self)
            //            }
            break;
        case is GameOverState:
            
            if nodeAtPoint.name == "tapToPlay" {
                restartGame()
            }
            
        default:
            break;
        }
    }

  //MARK: - 時時更新
    override func update(_ currentTime: TimeInterval) {
        /// 獲取時間差
        if lastUpdateTimeInterval == 0 {
            lastUpdateTimeInterval = currentTime
        }
        dt = currentTime - lastUpdateTimeInterval
        lastUpdateTimeInterval = currentTime
        stateMachine.update(deltaTime: dt)  // 調用所有State內的update方法
    }

}
 

二、MenuState.swft

//
//  MenuState.swift
//  Copyright © 2018 iFiero. All rights reserved.
//

import SpriteKit
import GameplayKit

class MenuState:GKState {
    
    // 必須引入場景(如:GameScene)
    unowned let scene:GameScene

    // 執行didEnter前，可在init()初始化代碼
    init(scene:SKScene){
        self.scene = scene as! GameScene
        super.init()
        print("Menu State")
    }
    // 進入當前狀態時觸發
    override func didEnter(from previousState: GKState?) {
        
    }
    // 離開當前狀態時觸發
    override func willExit(to nextState: GKState) {
        
    }
    /* 返回一個布爾值
     * 該值指示當前處於該狀態的狀態機是否允許轉換到指定狀態
     * 通俗點講就是：如果stateMachine(狀態機)的狀態是PlayState,那麽就從MenuState狀態轉到PlayState狀態
    */
    override func isValidNextState(_ stateClass: AnyClass) -> Bool {
        return stateClass is PlayState.Type
    }
    
    // Execute Update Per Frame,遊戲運行過程中的每一幀都會執行
    // 但須在GameScene update內調用stateMachine.update()
    override func update(deltaTime seconds: TimeInterval) {
        
    }
}


 

三、PlayingState.swft

import SpriteKit
import GameplayKit

class PlayState:GKState {
    unowned let scene:GameScene
    
    init(scene:SKScene){
        self.scene = scene as! GameScene
        super.init()
        print("Play State")
    }
    
    override func didEnter(from previousState: GKState?) {
        
    }

    // 挑戰:創建遊戲暫停GKState狀態 PauseState.swift
    // return (stateClass == PauseState.self) || (stateClass == GameOverState.self)
    override func isValidNextState(_ stateClass: AnyClass) -> Bool {
        return stateClass is GameOverState.Type
        
    }
    
    // Excute Update Per Frame
    override func update(deltaTime seconds: TimeInterval) {
        // update 用於判斷球的速度是否過快，如果太快了則設置linearDamping的阻力
    }
    
}

 

四、GameOverState.swft

import SpriteKit
import GameplayKit

class GameOverState:GKState {
    
    unowned let scene:GameScene
    init(scene:SKScene){
        self.scene = scene as! GameScene
        super.init()
    }
    
    override func didEnter(from previousState: GKState?) {
        print("GameOver State 遊戲結束")
    }
    
    override func isValidNextState(_ stateClass: AnyClass) -> Bool {
        return stateClass is PlayState.Type
       // return (stateClass == PlayState.self) || (stateClass == MenuState.self)
    }
}

更多遊戲教學：http://www.iFIERO.com -- 為遊戲開發深感自豪

源碼傳送門:https://github.com/apiapia/BreakOutGameVansVTutorial

GameplayKit的GKStateMachine用法與實例