Unity 2d 鼠标右键实现瞄准并发射子弹

把鼠标放在小怪的方向上，按下右键发射

瞄准精度如图开挂

效果

部分脚本

        //按下鼠标左键，开枪
        if (Input.GetMouseButtonDown(1) && curBulletCount > 0)
        {
            RaycastHit2D raycast = Physics2D.Raycast(Camera.main.ScreenToWorldPoint(Input.mousePosition), Vector2.zero);
            Vector2 hitPoint = new Vector2(raycast.point.x, raycast.point.y);
            Vector2 curposition = new Vector2(gameObject.transform.position.x, gameObject.transform.position.y);
            Vector2 ShootDirection = hitPoint - curposition;
            ChangeBulletCount(-1);
            anim.SetTrigger("Launch");
            AudioManager.instance.AudioPlay(launchClip);
            GameObject bullet = Instantiate(bulletPrefab, rbody.position + Vector2.up * 0.5f, Quaternion.identity);
            BulletControl bc = bullet.GetComponent<BulletControl>();
            if (bc != null)
            {
                bc.Shoot(ShootDirection, 300);//lookDirection
            }
        }

完整脚本

using System.Collections;
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;

public class PlayerControl : MonoBehaviour
{
    //主角速度
    public float speed = 8f;
    //定义2d刚体
    Rigidbody2D rbody;
    //定义动画
    Animator anim;
    //初始向x看
    Vector2 lookDirection = new Vector2(1, 0);

    //定义一个机器人对象
    GameObject robotObj;
    //最大健康值
    private int maxHealth = 2;//改为2;
    //当前健康值
    private int currentHealth;
    //其他脚本可获取最大健康值
    public int MyMaxHealth { get { return maxHealth; } }
    //其他脚本可获取当前健康值
    public int MyCurrentHealth { get { return currentHealth; } }

    //无敌时间
    private float wuditime = 2f;
    //无敌计时器
    private float wuditimer;
    //无敌状态
    private bool isWudi;

    //子弹数量
    [SerializeField]
    private int curBulletCount=1;

    private int maxBulletCount=6;

    public int MyCurBulletCount { get { return curBulletCount; } }
    public int MyMaxBulletCount { get { return maxBulletCount; } }
    //子弹预制体
    public GameObject bulletPrefab;

    //敌人剩余数量
    public static int enemyleft;
    //public int curEnemyleft { get { return enemyleft; } }

    //游戏结束提示
    public GameObject GameOver;
    //指定为主角并销毁
    public GameObject GameOverPlayer;
    //任务完成提示
    public GameObject MissionCompleted;
    //无法实现在其他脚本中销毁提示，故在此脚本中限时销毁
    public float showTime = 4;
    private float showTimer;

    //任务完成标记，显示标志，一场游戏中只显示一次
    public static int showflag=0;

    //玩家音效
    public AudioClip hitClip;
    public AudioClip launchClip;

    // Start is called before the first frame update
    void Start()
    {
        //任务完成状态的初始化
        showflag = 0;
        //隐藏任务完成提示
        MissionCompleted.SetActive(false);
        //提示计时器设置为负值
        showTimer = -1;
        //开始游戏后初始化敌人数量
        SetEnemyNum();


        //获取2d刚体
        rbody = GetComponent<Rigidbody2D>();
        //获取动画组件
        anim = GetComponent<Animator>();


        //初始化生命值
        currentHealth = 1;
        //初始化无敌时间
        wuditimer = 0;
        //更新生命条与子弹数量
        UIManager.instance.UpdateHealthBar(currentHealth, maxHealth);
        UIManager.instance.UpdateBulletCount(curBulletCount, maxBulletCount);
    }

    // Update is called once per frame
    void Update()
    {
        //任务完成显示 计时器
        showTimer -= Time.deltaTime;

        //超过时间就取消显示任务完成
        if (showTimer < 0)
        {   
            MissionCompleted.SetActive(false);
        }

        //敌人数量为0，并且是第一次达到0，之前没有完成任务，任务完成
        if (enemyleft==0 && showflag != 1)
        {
            //给倒计时器赋值，以此显示提示
            showTimer = showTime;
            //已经完成任务了，标记一下，之后不再显示
            showflag = 1;
            //显示任务完成提示
            MissionCompleted.SetActive(true);
        }
        
        //如果生命值为0，显示游戏结束字样，并销毁主角
        if (currentHealth==0)
        {
            GameOver.SetActive(true);
            Destroy(GameOverPlayer);
        }
        
        //获取运动矢量
        float moveX = Input.GetAxisRaw("Horizontal");
        float moveY = Input.GetAxisRaw("Vertical");

        Vector2 moveVector = new Vector2(moveX, moveY);

        if(moveX!=0||moveY!=0)
        {
            lookDirection = moveVector;
        }

        Vector2 position = transform.position;
        position.x += moveX * speed * Time.deltaTime;
        position.y += moveY * speed * Time.deltaTime;

        transform.position = new Vector2(position.x, position.y);
        //用刚体移动可以消除画面抖动
        rbody.MovePosition(position);

        //为动画集赋值
        //状态集的切换由运动矢量决定
        anim.SetFloat("move X",lookDirection.x);
        anim.SetFloat("move Y",lookDirection.y);
        anim.SetFloat("runspeed", moveVector.magnitude);
        //赋值必须与状态集命名一样

        
        //如果处于无敌状态，就计时
        if(isWudi)
        {
            wuditimer -= Time.deltaTime;
            //计时器归0，就不处于无敌状态了
            if(wuditimer<0)
            {
                isWudi = false;
            }
        }
        
        //当按下J，并且子弹大于0，开火
        if(Input.GetKeyDown(KeyCode.J) && curBulletCount>0)
        {
            ChangeBulletCount(-1);
            anim.SetTrigger("Launch");
            AudioManager.instance.AudioPlay(launchClip);
            GameObject bullet = Instantiate(bulletPrefab, rbody.position+Vector2.up*0.5f, Quaternion.identity);
            BulletControl bc = bullet.GetComponent<BulletControl>();
            if(bc!=null)
            {
                bc.Shoot(lookDirection, 300);
            }
        }
        //按下鼠标左键，开枪
        if (Input.GetMouseButtonDown(1) && curBulletCount > 0)
        {
            RaycastHit2D raycast = Physics2D.Raycast(Camera.main.ScreenToWorldPoint(Input.mousePosition), Vector2.zero);
            Vector2 hitPoint = new Vector2(raycast.point.x, raycast.point.y);
            Vector2 curposition = new Vector2(gameObject.transform.position.x, gameObject.transform.position.y);
            Vector2 ShootDirection = hitPoint - curposition;
            ChangeBulletCount(-1);
            anim.SetTrigger("Launch");
            AudioManager.instance.AudioPlay(launchClip);
            GameObject bullet = Instantiate(bulletPrefab, rbody.position + Vector2.up * 0.5f, Quaternion.identity);
            BulletControl bc = bullet.GetComponent<BulletControl>();
            if (bc != null)
            {
                bc.Shoot(ShootDirection, 300);//lookDirection
            }
        }
        //按E与npc交互
        if (Input.GetKeyDown(KeyCode.E))
        {
            RaycastHit2D hit = Physics2D.Raycast(rbody.position, lookDirection, 2f, LayerMask.GetMask("NPC"));
            if(hit.collider!=null)
            {
                Debug.Log("hit npc!");
                NPCManager npc = hit.collider.GetComponent<NPCManager>();
                if(npc!=null)
                {
                    npc.ShowDialog();
                }
            }
        }
    }

    private void OnTriggerEnter2D(Collider2D collision)
    {
        //踩到雷区，自动生成僵尸
        float robotX = Random.Range(-3, 5);
        float robotY = Random.Range(-3, 5);
        Vector2 position_robot = new Vector2(robotX, robotY);

        if(collision.gameObject.tag=="bomb")//如果碰到雷区
        {
            print("other.tag=" + collision.gameObject.tag);//这句一定要有，不然出不来
            robotObj = Instantiate(Resources.Load("Prefabs/Robot"),position_robot,Quaternion.identity)as GameObject;//加载资源,生成一个预制体，做成一个对象
        }
    }

    private void OnTriggerExit2D(Collider2D collision)
    {
        //离开雷区，僵尸消失
        if(collision.gameObject.tag=="bomb")
        {
            Destroy(robotObj);
        }
    }

    public void changeHealth(int amount)
    {
        //可能是受到伤害，也可能是加血
        if(amount<0)
        {
            //如果是受伤，设置无敌状态，则2秒内不能受伤
            if(isWudi==true)
            {
                return;
            }
            isWudi = true;
            //播放受伤动画
            anim.SetTrigger("Hit");
            //播放受伤音效
            AudioManager.instance.AudioPlay(hitClip);
            //为无敌计时器赋值
            wuditimer = wuditime;
        }
        //更改健康值
        currentHealth = Mathf.Clamp(currentHealth+amount,0,maxHealth);
        //更新血条
        UIManager.instance.UpdateHealthBar(currentHealth, maxHealth);
        //调试
        Debug.Log(currentHealth + "/" + maxHealth);
    }

    public void ChangeBulletCount(int amount)
    {
        //改变子弹数
        curBulletCount = Mathf.Clamp(curBulletCount + amount, 0, maxBulletCount);
        //改变UI子弹数
        UIManager.instance.UpdateBulletCount(curBulletCount, maxBulletCount);
    }

    void SetEnemyNum()
    {
        int index = SceneManager.GetActiveScene().buildIndex;
        if(index==1)
        {
            enemyleft = 2;
        }
        if(index==2)
        {
            enemyleft = 3;
        }
    }
}

附完整教程：

Unity2d Rubys Adventure 课程设计报告