【跟我一起学Unity3D】做一个2D的90坦克大战之AI系统

标签：unity3d   ai   

对于AI，我的初始想法很简单，首先他要能动，并且是在地图里面动， 懂得撞墙后转弯，然后懂得射击，其他的没有了，基于这个想法，我首先创建了一个MyTank类，用于管理玩家的坦克的活动，然后创建AITank类，AITank类继承MyTank类，这样的话，在AITank类上，只需要增加AI就可以了，具体的状态机实现，就放到MyTank类上即可。

首先来分析一下MyTank这个类，就从有限状态机开始吧。

一辆坦克的状态有下面几个：

    protected enum State
    {
        Idle,
        LeftWalk,
        RightWalk,
        UpWalk,
        DownWalk,
        Fire
    };

然后就是分别实现每个状态，首先是转向：

    protected void UpdateRotate(State state)
    {
        switch (state)
        {
            case State.LeftWalk:
                this.transform.rotation = Quaternion.identity;
                this.transform.Rotate(Vector3.forward * m_fAngle);
                m_curAngle = Vector3.left;
                break;
            case State.RightWalk:
                this.transform.rotation = Quaternion.identity;
                this.transform.Rotate(Vector3.forward * -m_fAngle);
                m_curAngle = Vector3.right;
                break;
            case State.UpWalk:
                this.transform.rotation = Quaternion.identity;
                m_curAngle = Vector3.up;
                break;
            case State.DownWalk:
                this.transform.rotation = Quaternion.identity;
                this.transform.Rotate(Vector3.forward * m_fAngle * 2);
                m_curAngle = Vector3.down;
                break;
        }
    }

    public virtual void UpdateState()
    {
        Debug.Log(m_sName + ":UpdateState()");
        switch (m_curState)
        {
            case State.Idle:
                break;
            case State.LeftWalk:
                this.transform.position += Vector3.left * Time.deltaTime * m_fMoveSpeed;
                break;
            case State.UpWalk:
                this.transform.position += Vector3.up * Time.deltaTime * m_fMoveSpeed;
                break;
            case State.DownWalk:
                this.transform.position += Vector3.down * Time.deltaTime * m_fMoveSpeed;
                break;
            case State.RightWalk:
                this.transform.position += Vector3.right * Time.deltaTime * m_fMoveSpeed;
                break;
            case State.Fire:
                doFire();
                break;
        }
    }

    protected virtual void doFire()
    {
        GameObject bullet = Instantiate(m_gBullet) as GameObject;
        bullet.name = m_sName + "Bullet";
        bullet.GetComponent<CBullet>().m_vDirection = m_curAngle;
        bullet.GetComponent<CBullet>().m_fMoveSpeed = m_fMoveSpeed + 1.0f;
        bullet.transform.position = new Vector3(this.transform.position.x, this.transform.position.y,0);
        Destroy(bullet, 5.0f);
    }

    void Update()
    {
        SetCurState(State.Idle);
        //转向
        if (Input.GetKey(KeyCode.A))
        {
            UpdateRotate(State.LeftWalk);
            SetCurState(State.LeftWalk);
        }
        if (Input.GetKey(KeyCode.W))
        {
            UpdateRotate(State.UpWalk);
            SetCurState(State.UpWalk);
        }
        if (Input.GetKey(KeyCode.S))
        {
            UpdateRotate(State.DownWalk);
            SetCurState(State.DownWalk);
        }
        if (Input.GetKey(KeyCode.D))
        {
            UpdateRotate(State.RightWalk);
            SetCurState(State.RightWalk);
        }
        if (Input.GetKeyDown(KeyCode.K))
        {
            SetCurState(State.Fire);
        }
        UpdateState();
    }

    protected void SetCurState(State curState)
    {
        if (curState != m_curState)
            m_lastState = m_curState;
        m_curState = curState;
    }

    void OnTriggerEnter2D(Collider2D other)
    {
        Debug.Log(m_sName + " OnTriggerEnter : " + other.gameObject.name);
        //被打中了
        if (other.gameObject.name == "AIBullet")
        {
            Destroy(other.gameObject);
            if (Camera.main.GetComponent<CCamera>().ReduceMyLeft() > 0)
            {
                GameObject temp = Instantiate(m_BoomAnimation, this.gameObject.transform.position, Quaternion.identity) as GameObject;
                Destroy(temp, 0.5f);
                string name = this.gameObject.name;
                GameObject temp_tank = Instantiate(this.gameObject, m_initPosition, Quaternion.identity) as GameObject;
                temp_tank.name = name;
            }
            else
            {
                //你输了
                Camera.main.GetComponent<CCamera>().m_bIsLose = true;
            }
            Destroy(this.gameObject);

        }
    }

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下面到了AITank的实现，AITank主要是添加一些触发器，例如检测到碰撞就转弯，每隔两秒就发射子弹等等，作为一个非常简单的AI，就不需要考虑那么多。首先是碰撞检测：

    void OnCollisionEnter2D(Collision2D coll)
    {
        Debug.Log(m_sName + " OnCollisionEnter2D : " + coll.gameObject.name);
        ChangeStateFromWall();
    }

    void ChangeStateFromWall()
    {
        switch (m_curState)
        {
            case State.Idle:
                SetCurState(State.DownWalk);
                break;
            case State.LeftWalk:
                SetCurState(State.UpWalk);
                break;
            case State.UpWalk:
                SetCurState(State.RightWalk);
                break;
            case State.DownWalk:
                SetCurState(State.LeftWalk);
                break;
            case State.RightWalk:
                SetCurState(State.DownWalk);
                break;
            case State.Fire:
                SetCurState(m_lastState);
                break;
        }
        this.UpdateRotate(m_curState);
    }
}

然后到开火，开火的设定非常简单，调用到一个函数：InvokeRepeating，这个是一个重复定时器，函数原型为：

void InvokeRepeating (string methodName,float time,float repeatRate) 

我们需要的是在AI坦克生成后一秒发射子弹 然后周期是每隔两秒发射一次，所以在Start函数中应该这么写：

        //每隔2秒开一次火
        InvokeRepeating("doFire", 1, 2);

    protected override void doFire()
    {
        base.doFire();
    }

上面就是AI的基本功能了，以后可以慢慢优化它，使它成为一个强大的AI。

【跟我一起学Unity3D】做一个2D的90坦克大战之AI系统

标签：unity3d   ai   

原文地址：http://blog.csdn.net/nxshow/article/details/40677851