unity TouchCamera相机触摸控制旋转、缩放、平移

脚本挂在相机下，相机在非正交下有选中和缩放功能；相机在正交下有缩放和平移功能。

using UnityEngine;
public class TouchCamera : MonoBehaviour
{
    public bool canPan = true;
    public bool canScale = true;

    public MouseSettings mouseSettings = new MouseSettings(0, 10, 10);

    public Range angleRange = new Range(0, 90);
    public Range distanceRange = new Range(1, 1000);

    //around center
    public Transform target;

    private Vector2 oldPos1;
    private Vector2 oldPos2;

    private bool m_isSinleFinger;

    private Vector3 targetPan;
    private Vector3 currentPan;

    private Vector2 targetAngles;
    private Vector2 currentAngles;

    private float targetDistance;
    private float currentDistance;

    private bool getCurrentDA = true;

    //Damper(阻尼) for move and rotate
    [Range(0, 10)]
    private float damper = 2;

    void Start()
    {
        GameObject camTargetObj = GameObject.Find("Main Camera Target");
        if (camTargetObj == null)
            camTargetObj = new GameO