游戏开发中的设计模式——状态模式

Siki学院——游戏开发中的设计模式

状态模式—— 菜鸟篇个人学习笔记

案例开发——应用于场景转换

由StartState场景，自动跳转到MainMenuState场景，点击按钮后，跳转到BattleState场景

 GameLoop

采用了脚本和游戏物体分离的开发模式

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.EventSystems;

public class GameLoop : MonoBehaviour {

    private SceneStateControl controller = null;

    void Awake() {
        DontDestroyOnLoad(this.gameObject);
    }


	void Start () {
        controller = new SceneStateControl();
        controller.SetState(new StartState(controller),false);//设置默认状态 为开始状态,不需要加载场景
	}
	

	void Update () {
        controller.StateUpdate();
	}
}

SceneStateControl

using System;
using System.Collections.Generic;
using System.Text;
using UnityEngine;
using UnityEngine.SceneManagement;

public class SceneStateControl
{
    private ISceneState mState;
    private AsyncOperation mAO;
    private bool mIsRunStart = false;
    /// <summary>
    /// 设置状态（场景）
    /// </summary>
    /// <param name="state"></要设置的状态，即却换到那个状态>
    /// <param name="isLoadScene"></增加判断是否需要加载场景>
    public void SetState(ISceneState state,bool isLoadScene=true) //增加判断是否需要加载场景
    { 
        if(mState!=null)
        {
            mState.StateEnd();//让上一个场景做一下清理工作    
        }
        mState = state;      //设置新状态
        if(isLoadScene)
        {
            mAO = SceneManager.LoadSceneAsync(mState.SceneName);//异步加载，返回一个AsyncOperation
            //mState.StateStart();//若LoadScene直接写在这里，可能出现场景还没加载完成，就执行了例如夹杂组件之类的操作，会出现问题
            mIsRunStart = false;
        }
        else
        {
            mState.StateStart();    //执行进入状态方法
            mIsRunStart = true ;
        }
       
    }

    public void StateUpdate() {
        if (mAO != null && mAO.isDone == false) return;

        if (mIsRunStart==false&& mAO != null && mAO.isDone == true)
        {
            mState.StateStart();    //执行进入状态方法
            mIsRunStart = true;
        }
        if (mState!=null)
        {
            mState.StateUpdate();
        }
    }
}

 ISceneState

using System;
using System.Collections.Generic;
using System.Text;
using UnityEngine;

public  class ISceneState
{
    private string mSceneName;
    protected SceneStateControl mControler;

    public ISceneState(string  sceneName, SceneStateControl controller) {
        mSceneName = sceneName;
        mControler = controller;
    }

    public string SceneName {
        get { return mSceneName; }
    }

    public virtual void StateStart() { }//进入状态时--例：得到场景中的组件
    public virtual void StateEnd() { }//离开状态时--例：销毁游戏物体
    public virtual void StateUpdate() { }//状态中的操作
}

具体状态（StartState、MainState、AttackState） 

StartState

using UnityEngine.UI;
using UnityEngine;

public  class StartState:ISceneState
{
    public StartState(SceneStateControl controller): base("01StartScene",controller)
    { 
        
    }

    private Image mLogo;
    private int mSmothTime=1;
    private float mWaitTime = 2;

    public override void StateStart()
    {
        mLogo = GameObject.Find("BG").GetComponent<Image>();
        mLogo.color = Color.black;
    }

    public override void StateUpdate()
    {
        mLogo.color = Color.Lerp(mLogo.color,Color.white,mSmothTime*Time.deltaTime);
        mWaitTime -= Time.deltaTime;
        if (mWaitTime<=0)
        {
            mControler.SetState(new MainState(mControler));
        }

    }
}

MainState

using System;
using System.Collections.Generic;
using System.Text;
using UnityEngine;
using UnityEngine.UI;


public  class MainState:ISceneState
{
    public MainState(SceneStateControl controller): base("02MainScene", controller)
    { 
        
    }

    public override void StateStart()
    {
        GameObject.Find("StartButton").GetComponent<Button>().onClick.AddListener(OnStartBtnClick);
    }

    private void OnStartBtnClick() 
    {
        mControler.SetState(new AttackState(mControler));
    }
}

 AttackState

using System;
using System.Collections.Generic;
using System.Text;

public  class AttackState:ISceneState
{
    public AttackState(SceneStateControl controller): base("03AttackScene", controller)
    { 
        
    }
}