using System.Collections;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;

public class BGManager : MonoBehaviour
{
    //private float height;
    public Vector3 upV3;
    public Vector3 centerV3;
    public Vector3 downV3;
    private float currHeight;
    public float speed;
    public float height;
    // Start is called before the first frame update
    void Start()
    {
        //设置背景布局
        //height = Screen.height*3;
        upV3 = Vector3.up * Screen.height*2;
        centerV3 = Vector3.up * Screen.height;
        downV3 = Vector3.zero;
        upV3 = CoordinateTransformation.ScreenToCamera(upV3);
        centerV3 = CoordinateTransformation.ScreenToCamera(centerV3);
        downV3 = CoordinateTransformation.ScreenToCamera(downV3);
        transform.GetChild(0).position = upV3;
        transform.GetChild(1).position = centerV3;
        transform.GetChild(2).position = downV3;
        height = upV3.y - centerV3.y;
    }
    // Update is called once per frame
    void Update()
    {
        float step = Time.deltaTime * speed;
        currHeight += step;
        foreach (Transform t in transform)
        {
            t.Translate(Vector3.down * step);
        }

        if (currHeight > height*1.3f)
        {

            currHeight -= height;
            Vector3 v3 = transform.GetChild(2).position;
            v3.y += height*3;
             transform.GetChild(2).position= v3;
            transform.GetChild(2).SetAsFirstSibling();
        }
        

    }
}