Am Freitag, 2. November 2007 23:33:20 schrieb Stephane Denis:
> > EXT_blend_equation_separate and EXT_blend_func_separate (5575773)
>
> It's part of OpenGL core 1.4 and 2.0 now. So you can check the GL_VERSION
Which is a *huge* pain if you're trying to write a cross platform application.
The ATI Linux driver advertises opengl 2.0, but some features like NP2
textures are software emulated. To reflect that, it doesn't show
GL_ARB_texture_non_power_of_two support.
So best practise on fglrx is not to use any feature that is not advertised as
an extension. Best practise on MacOS seems to be to check the GL core version
and add some additional features as extension. To do this, both driver have
to be detected reliably, which is next to impossible and against the general
opengl idea...
I don't want to judge which driver is "right" in its behavior. Both make
sense, but combined together it makes a lot of trouble.
What I also dislike is the inconsistency regarding advertising extensions that
made it to the core. Some are kept available as
extension(GL_ARB_vertex_shader for instance), while others aren't(the ones
mentioned in this thread). As far as I know it it is convention among drivers
for other OSes to advertise *all* extensions that are part of the supported
OpenGL version. Removing extensions like GL_ATI_pn_triangles which never made
it to the core is fine, but removing extensions which are part of the GL core
version needlessly breaks compatibility with old apps.
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