On Thu, 08 Sep 2011 20:13:45 +0200, Roland Scheidegger <srol...@vmware.com> wrote: > Am 08.09.2011 19:59, schrieb Eric Anholt: > > On Thu, 08 Sep 2011 10:53:45 -0700, Ian Romanick <i...@freedesktop.org> > > wrote: > >> -----BEGIN PGP SIGNED MESSAGE----- > >> Hash: SHA1 > >> > >> On 09/06/2011 03:21 PM, Roland Scheidegger wrote: > >>> EXT_blend_equation_separate allows some unholy combinations which the > >>> r200 (possibly other hw too) can't handle correctly. Namely this > >>> combination makes it possible to have logic ops on rgb or alpha channels > >>> and color blending on the other channels. > >>> I know that at least sometime in the past this driver did not advertize > >>> EXT_blend_logic_op, since OpenGL 1.1 style logic ops do not have that > >>> problem and EXT_blend_logic_op wasn't really all that important. I guess > >>> though it's not exactly a severe problem since surely apps old enough to > >>> use EXT_blend_logic_op wouldn't try to use EXT_blend_equation_separate > >>> (though in theory some app could be clever and really want to do that...). > >> > >> That's a good point. I suspect that no hardware actually handles this > >> case correctly. I seem to recall that this is the reason NVIDIA doesn't > >> support GL_EXT_blend_logic_op in their drivers. I know the non-Quadro > >> cards don't support it, anyway. > >> > >> Does this work on later chips in the Radeon family? > >> > >> I don't think anyone will miss GL_EXT_blend_logic_op if we just remove > >> it altogether. > > > > Sadly, for the purpose of doing X on top of GL, we actually do want > > logic ops. > > Yes but do we need GL_EXT_blend_logic_op and not the GL 1.1 style logic ops?
Oh, I guess what I was looking for was just GL 1.1 logic ops. I assumed that was what this was. None of the apps I have extension usage for used this one, so I wouldn't miss it.
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