u3d摄像机截图

using System;
using UnityEngine;
using System.Collections;

public class TestCamreaCapture1 : MonoBehaviour {

    private string imagesPath;
    private int imageIndex = 0;

    private RenderTexture rt;
    private Texture2D screenShot;

    private System.Diagnostics.Stopwatch stopWatch;

    // Use this for initialization
    void Start () {
        imagesPath = Application.dataPath + "/../pic/";
        stopWatch = new System.Diagnostics.Stopwatch ();

        rt = new RenderTexture (Screen.width,Screen.height, 24);
        //将rt附给一个摄像机，这样这个摄像机实时渲染的结果就都在这个tex上了.
        GetComponent<Camera>().targetTexture = rt;
        screenShot = new Texture2D (Screen.width,Screen.height, TextureFormat.ARGB32, false);
    }
    
    // Update is called once per frame
    void Update () {
        StartCoroutine (ScreenShoot());
    }

    IEnumerator ScreenShoot(){
        yield return new WaitForEndOfFrame ();
        stopWatch.Start ();
        ScreenSave ();
        imageIndex++;
        stopWatch.Stop();
        Debug.Log (string.Format("generate one pic use {0} 'ms",stopWatch.ElapsedMilliseconds));
        stopWatch.Reset ();
    }

    private void ScreenSave(){
        //记住当前渲染纹理.
        var remeber = RenderTexture.active;
        //将相机的渲染结果设置为当前渲染.
        RenderTexture.active = rt;
        //读取
        screenShot.ReadPixels (new Rect (0, 0, Screen.width, Screen.height), 0, 0);
        byte[] bytes;
        bytes = screenShot.EncodeToJPG ();
        System.IO.File.WriteAllBytes (imagesPath + imageIndex +".jpg", bytes);
        //将之前的渲染纹理变成激活.
        RenderTexture.active = remeber;

    }
}

个人最喜欢这种方式，效率已经相当高了