Unity 获取虚拟相机的画面

void Fun(Camera m_Camera, string filePath)
    {
        RenderTexture rt = new RenderTexture(Screen.width, Screen.height, 16);
        m_Camera.targetTexture = rt;
        m_Camera.Render();
        RenderTexture.active = rt;
        Texture2D t = new Texture2D(Screen.width, Screen.height);
        t.ReadPixels(new Rect(0, 0, t.width, t.height), 0, 0);
        t.Apply();
        System.IO.File.WriteAllBytes(filePath, t.EncodeToPNG());
    }