I'm never seeing the active texture get updated on a Nvidia 750m Macbook with 10.11.5 (and all previous versions). The call doesn't produce an error, and nothing is ever copied. This is a problem since it is the only way to do FBO -> Texture. glBlitFramebuffer only handles elements FBO -> FBO. This has been broken for as long as I can remember, or else my copy code is incorrect. Has anyone else succesfully use this. Apologies that I have to post this to the ES forum, but Apple deleted the GL forum a long time ago.