First, the purpose

1. Wonder: Angry Birds: How to Make

2. Make study notes so that you can check them next time

2. Reference

1. SIKI Academy

good: URL to learn

3. Attention

1. Version

Unity2017.2.0f3

VS2019

UnityHUB 2.5.6

Action: 1:17 Put the particle system before the UI

1. Knowledge introduction

1. Set the particle system to be displayed before the UI

Operation: 2:18 Make the stars appear one by one

1. Remove the camera

1. Code: The Star Appears

1. Running result: success

How To: 3:19 Add Pause Animation

1. Solve the problem of error reporting

1. Code: Bird

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

/// <summary>
/// 【Author：xzy;Time:2021-12-28】
/// Function:小鸟身上的代码
/// </summary>
public class Bird : MonoBehaviour
{
    /// <summary>bool：是否点击</summary>
    private bool bIsClick = false;

    /// <summary>float：计算鸟和弹弓的距离的最大值</summary>
    public float fMaxdis = 3;

    /// <summary>SpringJoint2D：鸟身上弹簧的组件</summary>
    [HideInInspector]
    public SpringJoint2D sp;

    /// <summary>Rigidbody2D：鸟身上的物理组件</summary>
    [HideInInspector]
    private Rigidbody2D rg;

    /// <summary>Transform：弹弓右边的位置，目的：方便计算鸟和弹弓的距离</summary>
    public Transform rightPos;

    /// <summary>Transform：弹弓左边的位置，目的：方便划线【课程08弹弓画线操作：添加】</summary>
    public Transform leftPos;

    /// <summary>LineRenderer：弹弓右边的划线组件【课程08弹弓画线操作：添加】</summary>
    public LineRenderer right;

    /// <summary>LineRenderer：弹弓左边的划线组件【课程08弹弓画线操作：添加】</summary>
    public LineRenderer left;

    /// <summary>GameObject：特效【10游戏逻辑的判定，实现多只小鸟的飞出：添加】</summary>
    public GameObject boom;

    /// <summary>TestMyTrail：拖尾【12 - 添加小鸟飞出的拖尾效果：添加】</summary>
    private TestMyTrail myTrail;

    /// <summary>bool：是否可以移动【19添加暂停动画：添加】</summary>
    private bool bIsCanMove = true;

    private void Awake()
    {
        sp = this.GetComponent<SpringJoint2D>();//获取小鸟的弹簧组件
        rg = this.GetComponent<Rigidbody2D>();//获取小鸟身上的物理组件
        myTrail = GetComponent<TestMyTrail>();//获取组件【12 - 添加小鸟飞出的拖尾效果：添加】
    }

    /// <summary>
    ///【Author：xzy;Time:2021-12-28】
    /// Function: 鼠标按下
    /// </summary>
    private void OnMouseDown()
    {
        if (bIsCanMove)//【19添加暂停动画：添加】
        {
            bIsClick = true;
            rg.isKinematic = true;//按下小鸟，让其物理组件的动力学开启，从dynamic到kinematic
        }
    }

    /// <summary>
    ///【Author：xzy;Time:2021-12-28】
    /// Function: 鼠标抬起
    /// </summary>
    private void OnMouseUp()
    {
        if (bIsCanMove)//【19添加暂停动画：添加】
        {
            bIsClick = false;
            rg.isKinematic = false;//松开小鸟，让其物理组件的动力学关闭
            Invoke("Fly", 0.1f);//定时器：唤醒 小鸟飞出的逻辑

            right.enabled = false;//禁用画线组件【11解决重复划线和小鸟轮换速度突然变大的问题：添加】
            left.enabled = false;

            bIsCanMove = false;//【19添加暂停动画：添加】
        }
    }

    private void Update()
    {
        if (bIsClick)
        {
            //鼠标按下，进行位置的跟随，屏幕坐标转换为世界坐标
            transform.position = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            transform.position += new Vector3(0, 0, -Camera.main.transform.position.z);

            //进行位置限制
            if (Vector3.Distance(transform.position, rightPos.position) > fMaxdis)
            {
                Vector3 pos = (transform.position - rightPos.position).normalized;  //单位化向量：获取方向，鸟的向量减去右边弹弓的位置的向量
                pos *= fMaxdis; //最大长度的向量
                transform.position = pos + rightPos.position;
            }

            Line();
        }
    }

    /// <summary>
    ///【Author：xzy;Time:2021-12-29】
    /// Function: 处理松开小鸟飞出的逻辑
    /// </summary>
    void Fly()
    {
        myTrail.StartTrail();//开始拖尾【12 - 添加小鸟飞出的拖尾效果：添加】
        sp.enabled = false;//松开小鸟，取消掉弹簧组件，小鸟就会飞出
        Invoke("Next", 5);//定时器：一段时候后调用Next方法
    }

    /// <summary>
    ///【Author：xzy;Time:2021-12-29】【课程08弹弓画线操作：添加】
    /// Function: 画线
    /// </summary>
    void Line()
    {       
        right.enabled = true; //开启画线组件【11解决重复划线和小鸟轮换速度突然变大的问题：添加】
        left.enabled = true;

        right.SetPosition(0, rightPos.position);//画线：右边的起始位置：右边弹弓位置
        right.SetPosition(1, this.transform.position);//画线：右边的终点位置：小鸟位置

        left.SetPosition(0, leftPos.position);
        left.SetPosition(1, this.transform.position);
    }

    /// <summary>
    ///【Author：xzy;Time:2021-12-29】【10游戏逻辑的判定，实现多只小鸟的飞出：添加】
    /// Function: 下一只小鸟被弹
    /// </summary>
    private void Next()
    {
        GameManager._instance.birds.Remove(this);//移除列表中此时小鸟元素
        Destroy(this.gameObject);//摧毁这个小鸟
        Instantiate(boom, this.transform.position, Quaternion.identity);//产生特效
        GameManager._instance.NextBird();//下一只小鸟出现
    }

    /// <summary>
    ///【Author：xzy;Time:2021-12-29】【12 - 添加小鸟飞出的拖尾效果：添加】
    /// Function: 碰撞检测
    /// </summary>
    private void OnCollisionEnter2D(Collision2D collision)
    {
        myTrail.ClearTrail();//清除拖尾【12 - 添加小鸟飞出的拖尾效果：添加】
    }
}