Yeah, it's the worst spec I have ever read. I am using the GL3.1 spec instead. There is also a trivial interaction with ARB_color_buffer_float. If I read the 3.1 spec correctly, there is no way to store _unclamped_ values to a signed normalized texture when rendering to it without a call to glClampColorARB to disable fragment color clamping. BTW I am almost done with EXT_texture_snorm and am doing final testing. I will send patches soon along with ARB_color_buffer_float. Marek <div class="gmail_quote">On Tue, Mar 15, 2011 at 4:23 PM, Ian Romanick <<a href="mailto:idr@freedesktop.org">idr@freedesktop.org</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 <div class="im"> On 03/10/2011 02:46 PM, Marek Olšák wrote: > The specification of GL_EXT_texture_snorm says: > > OpenGL 3.0 is required. > > This extension is written against the OpenGL 3.0 specification. </div>And then all of the chapter headings in the spec say "Additions to Chapter # of the OpenGL 2.0 Specification". lol <div class="im"> > which simply means we cannot advertise the extension on GL2.1. Would > anyone be against violating the requirement? > > The thing is even some of GL2 hardware can do it, and GL3 likely won't > be supported anytime soon due to unresolved patent issues. </div>My recollection is that AMD (where all of the spec authors live) only wanted to advertise it with OpenGL 3.x, and they didn't want to specify the interactions. It looks like the only interactions are with GL_ARB_texture_rg. I think it's safe to advertise this on 2.x hardware as long as GL_ARB_texture_rg is also supported. This makes sense given that the most common usage is for normal maps. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Fedora - <a href="http://enigmail.mozdev.org/" target="_blank">http://enigmail.mozdev.org/</a> iEYEARECAAYFAk1/hFcACgkQX1gOwKyEAw+HzwCeLzt30HuvdcGrdxKazUkardHo 8LAAn3H8cSVuewCG3vCuqcVhHKLAvIxW =iVP5 -----END PGP SIGNATURE----- </blockquote></div>