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

//摄像机操作   
//删减版   在实际的使用中可能会有限制的需求  比如最大远离多少  最近距离多少   不能旋转到地面以下等
public class BaseCam : MonoBehaviour
{
    public static BaseCam Instance;
    /// <summary>
    /// 相机围绕的物体
    /// </summary>
    public Transform CenObj;//围绕的物体
    /// <summary>
    /// 旋转坐标
    /// </summary>
    private Vector3 Rotation_Transform;
    private new Camera camera;

    private void Awake()
    {
        Instance = this;
    }

    void Start()
    {
        camera = GetComponent<Camera>();
    }

    void Update()
    {
        if (CenObj == null)
            return;

        Ctrl_Cam_Move();
        Cam_Ctrl_Rotation();
    }

    [ContextMenu("测试")]
    public void Test()
    {
        Init(CenObj);
    }

    public void Init(Transform CenObj)
    {
        camera.transform.position = new Vector3(0, 1, -10);
        camera.transform.eulerAngles = Vector3.zero;

        this.CenObj = CenObj;
        Rotation_Transform = CenObj.position;
    }

    Vector3 mouseDownPoint;
    float mouseCamPositionY;
    //镜头的远离和接近
    public void Ctrl_Cam_Move()
    {
        if (Input.GetAxis("Mouse ScrollWheel") > 0)
        {
            transform.Translate(Vector3.forward * 0.1f);//速度可调  自行调整
        }
        if (Input.GetAxis("Mouse ScrollWheel") < 0)
        {
            transform.Translate(Vector3.forward * -0.1f);//速度可调  自行调整
        }

        /*优化移动方式*/
        if (Input.GetKeyDown(KeyCode.Mouse2))
        {
            mouseDownPoint = Input.mousePosition;
            mouseCamPositionY = transform.position.y;
        }
        if (Input.GetKey(KeyCode.Mouse2))
        {
            var delta = Input.mousePosition - mouseDownPoint;
            var tra = transform.position;
            tra.y = mouseCamPositionY - delta.y * 0.001f;
            transform.position = tra;
        }
    }
    //摄像机的旋转
    public void Cam_Ctrl_Rotation()
    {
        if (Input.GetKey(KeyCode.Mouse1))
        {
            var mouse_x = Input.GetAxis("Mouse X");//获取鼠标X轴移动
            var mouse_y = -Input.GetAxis("Mouse Y");//获取鼠标Y轴移动

            transform.RotateAround(Rotation_Transform, Vector3.up, mouse_x * 5);
            transform.RotateAround(Rotation_Transform, transform.right, mouse_y * 5);
        }
    }

}