using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
/********************************************************************************
*Create By CG
*Function 摄像机环绕某个物体旋转展示
*鼠标滚轮:镜头远近-按住鼠标右键,拖动鼠标:摄像机绕某个物体上下左右旋转
*********************************************************************************/
namespace ZXK.UTility
{
    public class CameraAroundCtrl : MonoBehaviour
    {
        /// <summary>
        /// 需要围绕的物体
        /// </summary>
        public Transform _CenObj;
        public float _RotSpeed = 256;
        public float _ZoomSpeed = 30;


        private float x = 0.0f;
        private float y = 0.0f;
        private float distance = 0.0f;


        public bool IsCameraMove = false;

        private void OnEnable()
        {
            Vector3 angles = transform.eulerAngles;
            x = angles.y;
            y = angles.x;
            distance = (transform.position - _CenObj.position).magnitude;
        }
        private void Update()
        {
          
        }
        private void LateUpdate()
        {

            if (!EventSystem.current.IsPointerOverGameObject())
            {
                SetCamDistance();
                SetCamRotation();
                IsCameraMove = true;
            }
            else
            {
                IsCameraMove = false;
            }

        }
        /// <summary>
        /// 设置摄像机距离物体远近
        /// </summary>
        private void SetCamDistance()
        {
            transform.localPosition += transform.forward * Input.mouseScrollDelta.y * Time.deltaTime * _ZoomSpeed;
            distance = (transform.position - _CenObj.position).magnitude;
        }



        /// <summary>
        /// 设置摄像机围绕物体旋转
        /// </summary>
        private void SetCamRotation()
        {
            float mouse_x = Input.GetAxis("Mouse X");
            float mouse_y = Input.GetAxis("Mouse Y");
            if (Input.GetKey(KeyCode.Mouse1))
            {
                x += mouse_x * _RotSpeed * Time.deltaTime;
                y -= mouse_y * _RotSpeed * Time.deltaTime;
                y = Mathf.Clamp(y, -90, 90);//防止翻跟头
                Quaternion rotation = Quaternion.Euler(y, x, 0);//利用欧拉角防止万向锁
                Vector3 position = rotation *new Vector3(0,0,-distance) + _CenObj.position;//求得旋转后位置
                transform.rotation = rotation;
                transform.position = position;
            }
        }
    }
}