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Re: [Public WebGL] readPixles() can't access float values (OES_texture_float interaction)

On Wed, Sep 21, 2011 at 4:56 PM, Chris Marrin <cmarrin@apple.com> wrote:
It is terrible if there is no guaranteed combination of FBO attachments. It will make using FBO's almost useless for this audience. I'd like to see a matrix of all the possible combinations and all of those that are supported by various hardware. I don't have time to make such a matrix, but if I did, I bet I'd see a pattern emerge that would allow us to give authors at least some guarantees. If not, I think it will be too hard for authors to use FBO's, IMHO.

I think it's terrible for desktop hardware, too.  I've always hated the FBO API, which vaguely says "your framebuffer might be incomplete for any reason, sorry, no, there's no way to automatically negotiate a format".  I don't think it's too hard for authors to use--I'm an author of OpenGL software and I've used it--but it's definitely a pain.

I'd love to see something done to improve this, to be sure, but as long as OpenGL ES is the backend for any implementations (as I assume it is, at least on mobile systems), it seems impossible for WebGL to provide any guarantees that ES itself doesn't (like "this RB combination will never return INCOMPLETE_ATTACHMENT).  I guess vendors could provide those guarantees on a hardware-by-hardware basis if they have internal knowledge of their particular ES implementation, but I'm guessing that wouldn't scale, especially on Android...

Glenn Maynard