Content is very simple, it is painting a picture,
Didn't use fbo, images are normal rendering, and then enable fbo, render to texture, color depth render to texture or buffer (rbo) (both methods tried), however, is a black screen after open the depth test showed that if close depth test can display images, but such depth information is lost,

I suspect the depth during the information has not been writing fbo (if this is really the great god give directions need what steps), but is carried out in accordance with the process of rendering, I don't know whether there will be other reasons?