学习内容： 搭建游戏环境，刚体和力的添加，控制小球跳跃给调整上下板的移动和相机跟随增加障碍物触发器

1.首先把场景搭建好，我们要一个有上下板子挡住的大致场景，同时将小球的刚体属性添加好，下一步我们给小球挂一个有向右移动的力的代码，然后加一个键盘控制小球跳跃

2.上下板的长度不可能无限长，所以我们让上下板和相机跟随小球用相对运动移动

   //相机跟随
   void Start () {
    offset = gameObject.transform.position.x - player.transform.position.x;
}
// Update is called once per frame
void Update () {
    gameObject.transform.position = new Vector3(offset+ player.transform.position.x, gameObject.transform.position.y, gameObject.transform.position.z);
}

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   //上下板跟随
    void Start () {
    offset = gameObject.transform.position.x - player.transform.position.x;
    
}
void Update()
{
    FollowPlayerMove();
}
// Update is called once per frame
void FollowPlayerMove () {
    gameObject.transform.position = new Vector3(player.transform.position.x+offset,0,0);
}

3.添加障碍物，在小球的运行过程中需要有障碍物，使用障碍物管理器，instantiate函数随机生成不同宽高的障碍物

	public class BarrierControl : MonoBehaviour {
public GameObject player;
public GameObject BarrierPre;
public GameObject CurrentBarrier;	
public int BarrierInterval = 10;
 void Start () {}
 void Update () {
    AutCreatBarrier();
}
public void AutCreatBarrier()
{
    if(player.transform.position.x>CurrentBarrier.transform.position.x)
    {
        //生成新的障碍物
        float targetX = CurrentBarrier.transform.position.x+BarrierInterval;
        float targetY = RandomBarrierPositionY();
        Vector3 targetPos = new Vector3(targetX,targetY,0);
        GameObject g = Instantiate(BarrierPre,targetPos,Quaternion.identity);
        g.transform.localScale = new Vector3(g.transform.localScale.x, RandomBarrierSizeY((int)g.transform.position.y),g.transform.localScale.z);
        CurrentBarrier = g;
    }
}
public float RandomBarrierSizeY(int y)
{
    int yAbs = Mathf.Abs(y);
    if(yAbs==0)
    {
        return 6;
    }
    else
    {
        return (3 - yAbs) * 2 - 1;
    }
}
public float RandomBarrierPositionY()
{
    int r = Random.Range(-3,3);
    return r;
}}

4.还需要一个触发器，当第一个障碍物碰到触发器，障碍物开始生成