using System.Collections;
using System.Collections.Generic;
using UnityEngine;
/// <summary>
/// 手指或鼠标控制摄像机旋转
/// 使用方法：将此脚本挂到Camera上
/// </summary>
public class TouchRotationCamera : MonoBehaviour
{
    public float aroundSpeed = 0.1f; //旋转速度
    public bool aroundX = true; //允许绕X轴旋转
    public bool aroundY = true; //允许绕Y轴旋转

    private Vector3 lastPosition;
    private Transform cacheTransfrom;
    private bool isMobilePlatform;

    void Awake()
    {
        cacheTransfrom = transform;
        isMobilePlatform = WebJS.IsMobilePlatform;
    }

    void LateUpdate()
    {
        //注意：
        //发布WebGL平台时，需借助JavaScript来判断浏览器运行平台。
        if (Application.platform == RuntimePlatform.WebGLPlayer)
        {
            if (isMobilePlatform)
                TouchRotation();
            else
                MouseRotation();
            return;
        }

        //设备是否支持触摸
        if (Input.touchSupported)
        {
            TouchRotation();
        }
        //是否探测到鼠标
        else if (Input.mousePresent)
        {
            MouseRotation();
        }
    }

    void MouseRotation()
    {
        if (Input.GetMouseButtonDown(0))
        {
            lastPosition = Input.mousePosition;
            return;
        }

        if (!Input.GetMouseButton(0))
            return;

        Vector3 mousePosition = Input.mousePosition;
        Vector3 offset = mousePosition - lastPosition;
        float t = -offset.x;
        offset.x = offset.y;
        offset.y = t;
        offset.z = 0;
        if (!aroundX)
            offset.x = 0;
        if (!aroundY)
            offset.y = 0;
        Vector3 euler = cacheTransfrom.eulerAngles;
        euler.x += offset.x * aroundSpeed;
        euler.y += offset.y * aroundSpeed;
        cacheTransfrom.eulerAngles = euler;
        lastPosition = mousePosition;
    }

    void TouchRotation()
    {
        int touchCount = Input.touchCount;
        if (touchCount <= 0)
            return;

        Vector3 firstTouch = Input.touches[0].position;
        if (Input.touches[0].phase == TouchPhase.Began)
        {
            lastPosition = firstTouch;
            return;
        }

        Vector3 offset = firstTouch - lastPosition;
        float t = -offset.x;
        offset.x = offset.y;
        offset.y = t;
        if (!aroundX)
            offset.x = 0;
        if (!aroundY)
            offset.y = 0;
        Vector3 euler = cacheTransfrom.eulerAngles;
        euler.x += offset.x * aroundSpeed;
        euler.y += offset.y * aroundSpeed;
        cacheTransfrom.eulerAngles = euler;
        lastPosition = firstTouch;
    }
}