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

public class PanoramaCameraOrbit : MonoBehaviour {

    
    //float yRotSpeed = 30f;
    public float mouseSensivity = 120;
    private Vector3 mousePrevPos;
    public float camMoveSpeed = 700f;
    public float camXRot = 0;
    public float camYRot = 0;
    public float camZRot = 0;
    public Vector3 camFreeModePos;
    float FildOfViewSpeed = 50; //视角拉近速度

    void Start()
    {
        
    }

    void Update()
    {
        Vector3 camPos = GetComponent<Camera>().transform.position;
        Vector3 camMoveDir = new Vector3();
        Vector3 camDesiredRot = Vector3.zero;

        if (mouseCursorInFrame())
        {
            if (Input.GetMouseButton(1))
            {
                camYRot -= Input.GetAxis("Mouse X") * (Time.deltaTime * mouseSensivity);
                camYRot = ClampAngle(camYRot, -360, 360);
                camXRot += Input.GetAxis("Mouse Y") * (Time.deltaTime * mouseSensivity);
                camXRot = ClampAngle(camXRot, -85, 85);
            }
            if (Input.GetAxis("Mouse ScrollWheel") > 0)
            {
                if (this.GetComponent<Camera>().fieldOfView > 50)
                {
                    camMoveDir = GetComponent<Camera>().transform.forward;
                    this.GetComponent<Camera>().fieldOfView -= Time.deltaTime * FildOfViewSpeed;//视角拉近

                }
                
            }
            if (Input.GetAxis("Mouse ScrollWheel") < 0)
            {
                if (this.GetComponent<Camera>().fieldOfView < 70)
                {
                    camMoveDir = -GetComponent<Camera>().transform.forward;
                    this.GetComponent<Camera>().fieldOfView += Time.deltaTime * FildOfViewSpeed;//视角拉远
                }
                    
            }
        }

        camDesiredRot = new Vector3(camXRot, camYRot, camZRot);
        camMoveDir.Normalize();
        camMoveDir *= (camMoveSpeed * Time.deltaTime);
        camFreeModePos += camMoveDir;
        Vector3 finalPosition = Vector3.Lerp(camPos, camFreeModePos, Time.deltaTime + 0.1f);
        GetComponent<Camera>().transform.position = finalPosition;
        GetComponent<Camera>().transform.rotation = Quaternion.Slerp(GetComponent<Camera>().transform.rotation, Quaternion.Euler(camDesiredRot), Time.deltaTime + 0.05f);
    }
    
    private bool mouseCursorInFrame()
    {
        Vector3 cursorPos = Input.mousePosition;
        float xMinCoord = Screen.width * GetComponent<Camera>().rect.xMin;
        float yMinCoord = Screen.height * GetComponent<Camera>().rect.yMin;
        float xMaxCoord = Screen.width * GetComponent<Camera>().rect.xMax;
        float yMaxCoord = Screen.height * GetComponent<Camera>().rect.yMax;
        if (cursorPos.x > xMinCoord && cursorPos.x < xMaxCoord &&
           cursorPos.y > yMinCoord && cursorPos.y < yMaxCoord)
            return true;
        else
            return false;
    }
    private static float ClampAngle(float angle, float min, float max)
    {
        if (angle < -360)
            angle += 360;
        if (angle > 360)
            angle -= 360;
        return Mathf.Clamp(angle, min, max);
    }
   
}