//可直接拷贝到项目中
  using System;
  using System.Collections;
  using System.Collections.Generic;
  using UnityEngine;

  namespace ImageEffect
  {
      public class Effect : MonoBehaviour
      {
          private static Effect instance = null;
          /*public Effect getInstance()
          {
              if (instance == null) 
              {
                  instance = new Effect();
              }
              return instance;
          }*/
          public Effect getInstance()
          {
              if (instance == null)
              {
                  instance = this;
              }
              return instance;
          }

          /// <summary>
          /// 物体缩放渐变协程
          /// 限制：最低帧数应大于30帧
          /// </summary>
          /// <param name="gameObject">渐变对象</param>
          /// <param name="fromScale">开始时大小scale</param>
          /// <param name="toScale">结束时大小scale</param>
          /// <param name="effect_time_s">渐变的时间，秒为单位</param>
          /// <param name="action">回调函数，可无</param>
          public void gradualChange(GameObject gameObject, Vector3 fromScale, Vector3 toScale, float effect_time_s = 1f, Action action = null)
          {
              StartCoroutine(gradualChangeEnum(gameObject,fromScale,toScale,effect_time_s,action));
          }


          /// <summary>
          /// 物体缩放渐变协程
          /// 参数说明：渐变对象 起始大小，终止大小，渐变时间(秒为单位)，回调函数（可无）
          /// 帧数限制：最低帧数大于30帧
          /// </summary>
          private IEnumerator gradualChangeEnum(GameObject gameObject, Vector3 fromScale, Vector3 toScale, float effect_time_s = 1f, Action action = null)
          {
              if(gameObject == null)
              {
                  Debug.LogError("gradual change error: gameObject is null");
                  yield return null;
              }
              if(effect_time_s == 0f)
              {
                  Debug.LogError("gradual change error:  effect time is zero");
                  yield return null;
              }

              float lastFrameTime = Time.time - 0.01f;
              float totalTime = 0;
              while (true)
              {
                  totalTime += (Time.time - lastFrameTime);

                  //缩放变化，依据经过的时间进行线性插值
                  gameObject.transform.localScale = Vector3.Lerp(fromScale, toScale, totalTime / effect_time_s);
                  lastFrameTime = Time.time;


                  //如果当前点达到了目标位置，并且在最小误差范围内，则归位，结束循环
                  if (Vector3.Distance(toScale, fromScale) / effect_time_s / 30 > Vector3.Distance(toScale, gameObject.transform.localScale))
                  {
                      gameObject.transform.localScale = toScale;
                      break;
                  }
                  //yield return new WaitForSeconds(0.04f);
                  yield return null;
              }
              if (action != null)
                  action();
          }
      }
  }