unity3d 将摄像头视野保存到图片

//把摄像头视野 打印出png图片
private Rect CutRect = new Rect(0, 0, 1, 1);
private  Image MakeCameraImg(Camera mCam,int width,int height)
{
Image mImage;
RenderTexture rt = new RenderTexture(width, height, 2);
mCam.pixelRect = new Rect(0, 0, Screen.width, Screen.height);
mCam.targetTexture = rt;
Texture2D screenShot = new Texture2D((int)(width * CutRect.width), (int)(height * CutRect.height),
TextureFormat.RGB24, false);
mCam.Render();
RenderTexture.active = rt;
screenShot.ReadPixels(new Rect(width * CutRect.x, width * CutRect.y, width * CutRect.width, height * CutRect.height), 0, 0);
mCam.targetTexture = null;
RenderTexture.active = null;
UnityEngine.Object.Destroy(rt);
byte[] bytes = screenShot.EncodeToPNG();
//string filename = Application.dataPath + "/Imgs/Img"
//                  + System.DateTime.Now.ToString("yyyy-MM-dd_HH-mm-ss") + ".png";
//System.IO.File.WriteAllBytes(filename, bytes);

mImage = Image.GetInstance(bytes);
return mImage;

}