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Re: [Public WebGL] 2.2 The Drawing Buffer requires 8 bit per color component





On Tue, May 29, 2012 at 1:19 PM, Glenn Maynard <glenn@zewt.org> wrote:
On Tue, May 29, 2012 at 11:25 AM, Gregg Tavares (社用) <gman@google.com> wrote:
Personally I'd prefer to go to the other way. Require 8bit support for renderbuffers. But in OpenGL ES 2.0 the only supported default is RGBA4. 

On the other hand, AFAIK, there are few use cases for color Renderbuffers. Instead people use textures since (a) they can then use the results to render with and (b) they can explicitly choose 8bits per pixel. That leaves the only good use case for Renderbuffers for creating depth and stencil buffers.

Oh, right--I thought it seemed unlikely that rendering to RGBA8 wasn't supported at all.  I'm a bit out of practice, apparently--renderbuffers are for rendering to surfaces that don't have a corresponding texture format.

Actually, I'm not sure what the purpose of RGBA4/RGB5A1/RGB565 renderbuffers are, since you can just bind a texture with those formats.  On the same token, what would be the benefit of supporting RGBA8 renderbuffers, instead of just binding a texture?

The purpose appears to be to give GPU vendors more ways to make crappy GPUs. :-p

According the OpenGL ES 2.0 spec 

There must exist, however, at least one combination of internal formats for which the framebuffer
cannot be FRAMEBUFFER_UNSUPPORTED

That basically means that as long as 1 renderbuffer format works ZERO texture formats are required to work or visa versa. :-(



--
Glenn Maynard