在之前有過介紹一個視覺化有限狀態機編輯器外掛PlayerMaker

在這裡也可以在我們的程式碼中實現一個狀態機

首先建立一個指令碼，來管理我們的各個狀態

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Linq;

/// <summary>
/// 狀態ID
/// </summary>
public enum FSMStateID
{
    NullFSMStateID,
    PatrolFSMStateID,//巡邏狀態
    ChaseFSMStateID,//追逐狀態
}


/// <summary>
/// 狀態轉化條件
/// </summary>
public enum FSMTransition
{
    SeePlayer,//看到主角（目標）
    LeavePlayer,//遠離敵人（目標）
}

public class FSMSystem
{
    private FSMStateID mCurrentStateID;
    private FSMBaseState mCurrentState;

    private Dictionary<FSMStateID, FSMBaseState> mFSMStateDic = new Dictionary<FSMStateID, FSMBaseState>();


    public void AddFSMSate(FSMBaseState state)
    {
        if (state == null)
        {
            Debug.Log("角色狀態為空，無法新增");
            return;
        }
        if (mCurrentState == null)
        {
            //第一個新增的狀態被作為系統首個執行的狀態
            mCurrentStateID = state.mStateID;
            mCurrentState = state;
            mCurrentState.StateStart();
        }
        if (mFSMStateDic.ContainsValue(state))
        {
            Debug.Log("容器記憶體在該狀態");
            return;
        }
        mFSMStateDic.Add(state.mStateID, state);
    }

    public void DeleteFSMSate(FSMBaseState state)
    {
        if (state == null)
        {
            Debug.Log("角色狀態為空，無法新增");
            return;
        }
        if (!mFSMStateDic.ContainsValue(state))
        {
            Debug.Log("容器內不存在該狀態");
            return;
        }
        mFSMStateDic.Remove(state.mStateID);
    }

    //更新（執行）系統
    public void UpdateSystem()
    {
        if (mCurrentState != null)
        {
            mCurrentState.StateUpdate();
            mCurrentState.TransitionReason();
        }
    }

    //轉換狀態
    public void TransitionFSMState(FSMTransition transition)
    {
        FSMStateID stateID = mCurrentState.GetStateIdByTransition(transition);
        if (stateID != FSMStateID.NullFSMStateID)
        {
            mCurrentStateID = stateID;
            mCurrentState.StateEnd();
            //換狀態
            mCurrentState = mFSMStateDic.FirstOrDefault(q => q.Key == stateID).Value;
            mCurrentState.StateStart();
        }
    }
}
 

各個狀態（巡邏狀態、追逐狀態）抽象理解為一個物件

建立一個狀態基類，各個狀態子類中可以繼承重寫這個基類方法

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Linq;

public abstract class FSMBaseState
{
    public FSMStateID mStateID { get; set; }    //狀態ID
    public FSMSystem mFSMSystem { get; set; }   //該物件屬於在哪個狀態機

    public Dictionary<FSMTransition, FSMStateID> mFSMStateIdDic = new Dictionary<FSMTransition, FSMStateID>();

    public FSMBaseState(FSMSystem fsmSystem, FSMStateID stateID)
    {
        this.mFSMSystem = fsmSystem;
        this.mStateID = stateID;
    }

    public void AddTransition(FSMTransition transition, FSMStateID stateID)
    {
        if (mFSMStateIdDic.ContainsKey(transition))
        {
            Debug.Log("本狀態已經包含了該轉換條件");
            return;
        }
        mFSMStateIdDic.Add(transition, stateID);
    }

    public void DeleteTransition(FSMTransition transition)
    {
        if (!mFSMStateIdDic.ContainsKey(transition))
        {
            Debug.Log("容器中沒有該轉換條件");
            return;
        }
        mFSMStateIdDic.Remove(transition);
    }

    public FSMStateID GetStateIdByTransition(FSMTransition transition)
    {
        if (!mFSMStateIdDic.ContainsKey(transition))
        {
            Debug.Log("容器內沒有該轉換條件，無法獲取狀態");
            return FSMStateID.NullFSMStateID;
        }

        return mFSMStateIdDic.FirstOrDefault(q => q.Key == transition).Value;
    }

    public abstract void StateStart();
    public abstract void StateUpdate();
    public abstract void StateEnd();
    //轉化狀態條件
    public abstract void TransitionReason();
}
 

以下是巡邏狀態

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

public class FSMPatrolState : FSMBaseState
{
    //路徑點
    private List<Transform> mStargetPointTransform = new List<Transform>();
    //路徑點索引
    private int mPointIndex = 0;
    //士兵
    private GameObject mSliderObj { get; set; }
    //主角
    private GameObject mPlayerObj { get; set; }
    //士兵移動速度
    private float mMoveSpeed = 4f;

    public FSMPatrolState(FSMSystem fsmSystem) : base(fsmSystem, FSMStateID.PatrolFSMStateID) { }

    public override void StateStart()
    {
        //獲取路徑點
        Transform[] transforms = GameObject.Find("Points").GetComponentsInChildren<Transform>();
        foreach (var m_transform in transforms)
        {
            if (m_transform != GameObject.Find("Points").transform)
            {
                mStargetPointTransform.Add(m_transform);
                Debug.Log(m_transform.position);
            }
        }

        //獲取士兵物件
        mSliderObj = GameObject.Find("Slider");
        //獲取主角物件
        mPlayerObj = GameObject.Find("Player");
    }

    public override void StateUpdate()
    {
        //確實目標點並移動  
        mSliderObj.transform.LookAt(this.mStargetPointTransform[this.mPointIndex].position);
        mSliderObj.transform.Translate(Vector3.forward * Time.deltaTime * mMoveSpeed);

        if (Vector3.Distance(mSliderObj.transform.position, this.mStargetPointTransform[this.mPointIndex].position) < 0.5f)
        {
            //切換目標點
            this.mPointIndex++;
            if (this.mPointIndex >= this.mStargetPointTransform.Count)
            {
                this.mPointIndex = 0;
            }    
        }
    }

    public override void StateEnd()
    {
        
    }

    public override void TransitionReason()
    {
        if (Vector3.Distance(mSliderObj.transform.position, mPlayerObj.transform.position) <= 2.0f)
        {
            //轉化狀態
            if (this.mFSMSystem == null)
            {
                Debug.Log("目標狀態機為空");
                return;
            }
            mFSMSystem.TransitionFSMState(FSMTransition.SeePlayer);
        }
    }
}
 

以下是追逐狀態

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

public class FSMChaseState : FSMBaseState
{
    private GameObject mPlayerObj { get; set; }
    private GameObject mSliderObj { get; set; }
    private float mSliderMoveSpeed = 6.0f;

    public FSMChaseState(FSMSystem fsmSystem) : base(fsmSystem, FSMStateID.ChaseFSMStateID) { }

    public override void StateStart()
    {
        mPlayerObj = GameObject.Find("Player");
        mSliderObj = GameObject.Find("Slider");
    }

    public override void StateUpdate()
    {
        if (Vector3.Distance(mPlayerObj.transform.position, mSliderObj.transform.position) <= 10.0f)
        {
            //開始面向主角
            mSliderObj.transform.LookAt(mPlayerObj.transform.position);
            //開始追逐
            mSliderObj.transform.Translate(Vector3.forward * Time.deltaTime * mSliderMoveSpeed);
        }
    }

    public override void StateEnd()
    {
        
    }

    public override void TransitionReason()
    {
        //當主角遠離敵人
        if (Vector3.Distance(mPlayerObj.transform.position, mSliderObj.transform.position) > 10.0f)
        {
            //轉化狀態
            if (this.mFSMSystem == null)
            {
                Debug.Log("目標狀態機為空");
                return;
            }
            mFSMSystem.TransitionFSMState(FSMTransition.LeavePlayer);
        }
    }
}

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

public class Slider : MonoBehaviour
{
    private FSMSystem fsmSystem { get; set; }

	void Start ()
    {
        fsmSystem = new FSMSystem();

        //巡邏狀態，在構造引數傳一個系統引數，確定該狀態是在哪個狀態系統中管理的，狀態轉換的時候呼叫
        FSMBaseState patrolState = new FSMPatrolState(fsmSystem);
        patrolState.AddTransition(FSMTransition.SeePlayer, FSMStateID.ChaseFSMStateID);//巡邏狀態轉化條件

        //追逐狀態
        FSMBaseState chaseState = new FSMChaseState(fsmSystem);
        chaseState.AddTransition(FSMTransition.LeavePlayer, FSMStateID.PatrolFSMStateID);
        
        fsmSystem.AddFSMSate(patrolState);
        fsmSystem.AddFSMSate(chaseState);
	}
	
	void Update ()
    {
        fsmSystem.UpdateSystem();	
	}
}