void OnGUI(){

        if(GUI.Button(new Rect(10,70,50,50),"ScreenShot")){

                    StartCoroutine(ScreenShot());  //协程调用

        }

    }

    IEnumerator ScreenShot(){

            int width = Screen.width;

            int height = Screen.height;

            yield return new WaitForEndOfFrame(); //去掉协程试试看会发生什么。

            Texture2D tex = new Texture2D(width,height,TextureFormat.RGB24,false);//设置Texture2D

            tex.ReadPixels(new Rect(0,0,width,height),0,0);//获取Pixels

            tex.Apply();//应用改变

            byte[] bytes = tex.EncodeToPNG();//转换为byte[]

　　　　　　　Destroy(tex);

            Stream flstr = new FileStream(@"d:\1.png", FileMode.Create);//文件操作

            BinaryWriter sw = new BinaryWriter(flstr, Encoding.Unicode);

            sw.Write(bytes);

            sw.Close();

            flstr.Close();    

    }

using UnityEngine; 

using System.Collections;

public class example : MonoBehaviour 

{ 

　　void OnMouseDown() 

　　{ 

　　　　Application.CaptureScreenshot("Screenshot.png"); 

　　} 

}

function OnGUI(){

    if(GUI.Button(Rect(Screen.width*0.5-,Screen.height*0.5-,,),"screen")){

        Application.CaptureScreenshot("Screenshot.png");

    }

 }