X11Drv: move WGL extension code
lionel.ulmer at free.fr
Tue Sep 12 03:17:49 CDT 2006
On Fri, Sep 01, 2006 at 01:57:24PM +0200, Roderick Colenbrander wrote:
> The way WGL extensions are loaded is different. The old code correctly
> advertised the names of available WGL extensions but the wglGetProcAddress
> code didn't work correctly. Even if an extension wasn't advertised you could
> get a function pointer to the functions. On Windows wglGetProcAddress would
> return NULL.
Note that (as far as I know), 'wglGetProcAddress' returns NULL on
non-existant extensions for all extensions, whether they are GL or WGL ones.
This means that our implementation of it is broken (at least on DRI / Mesa)
as 'glXGetProcAddress' may return a non-NULL value when querying a
So if we really want to be windows-like, we would need to add a 'function
name / extension name' database and check if the extension corresponding to
the function is present before actually calling 'glXGetProcAddress'.
But as I ever only once got a bug report linked to that, I never took the
pain to fix it :-)
Lionel (catching up his old mails)
PS: I guess that this 'database' may be automatically build by the
'make_opengl' script though so it should not be that hard to do :-)
Lionel Ulmer - http://www.bbrox.org/
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