原文連結：

http://blog.csdn.net/anyuanlzh/article/details/17008909

using UnityEngine;
using System.Collections;
using UnityEditor;

public class CaptureScreen : MonoBehaviour {
    void Start()
    {
        //Capture(); 
        //StartCoroutine(Capture2(new Rect(0, 0, Screen.width, Screen.height)));
        //Capture3(Camera.main, new Rect(0, 0, Screen.width, Screen.height));

        Camera uiCamera = GameObject.Find("UICamera").GetComponent<Camera>();
        Capture3(uiCamera, new Rect(0, 0, Screen.width, Screen.height));
    }

    public void Capture()
    {
        //儲存在工程的根目錄下
        Application.CaptureScreenshot("Screenshot.png");
        Debug.Log("Capture");
    }

    // 讀取螢幕畫素
    public IEnumerator Capture2(Rect rect)
    {
        // 先建立一個的空紋理，大小可根據實現需要來設定  
        Texture2D screenShot = new Texture2D((int)rect.width, (int)rect.height, TextureFormat.RGB24, false);

        // 讀取螢幕畫素資訊並存儲為紋理資料
        yield return new WaitForEndOfFrame();
        screenShot.ReadPixels(rect, 0, 0, false);
        screenShot.Apply();

        // 然後將這些紋理資料，成一個png圖片檔案  
        byte[] bytes = screenShot.EncodeToPNG();
        string filename = Application.dataPath + "/Screenshot2.png";
        System.IO.File.WriteAllBytes(filename, bytes);

        AssetDatabase.Refresh();
        Debug.Log(string.Format("截圖了一張圖片: {0}", filename));
    }

    // 讀取RenderTexture畫素
    Texture2D Capture3(Camera camera, Rect rect)
    {
        // 建立一個RenderTexture物件  
        RenderTexture rt = new RenderTexture((int)rect.width, (int)rect.height, 0);
        // 臨時設定相關相機的targetTexture為rt, 並手動渲染相關相機  
        camera.targetTexture = rt;
        camera.Render();
        //ps: --- 如果這樣加上第二個相機，可以實現只截圖某幾個指定的相機一起看到的影象。  
        //ps: camera2.targetTexture = rt;  
        //ps: camera2.Render();  
        //ps: -------------------------------------------------------------------  

        // 啟用這個rt, 並從中中讀取畫素。  
        RenderTexture.active = rt;
        Texture2D screenShot = new Texture2D((int)rect.width, (int)rect.height, TextureFormat.RGB24, false);
        screenShot.ReadPixels(rect, 0, 0);// 注：這個時候，它是從RenderTexture.active中讀取畫素  
        screenShot.Apply();

        // 重置相關引數，以使用camera繼續在螢幕上顯示  
        camera.targetTexture = null;
        //ps: camera2.targetTexture = null;  
        RenderTexture.active = null; // JC: added to avoid errors  
        GameObject.Destroy(rt);

        // 最後將這些紋理資料，成一個png圖片檔案  
        byte[] bytes = screenShot.EncodeToPNG();
        string filename = Application.dataPath + "/Screenshot3.png";
        System.IO.File.WriteAllBytes(filename, bytes);
        AssetDatabase.Refresh();
        Debug.Log(string.Format("截圖了一張照片: {0}", filename));

        return screenShot;
    } 
}