Re: [Mesa3d-users] glext.h

[Stephen J B. <sj...@li...>]

On Wed, 23 Aug 2000 de...@ko... wrote:

> Federico Carminati writes:
> >Hello,
> >  I am probably missing the obvious as I usually do, but installing the
> >latest Mesa 3.3 I noticed that glext.h is not copied in place when doing
> >make install, to the greatest pain and anguish of gl.h. I copied it
> >there and everything seems to work. What am I doing wrong??? Thanks .
> >Fed
> 
> I noticed this too, and "solved" it the same way by copying over glext.h.
> 
> However, I noticed that causes some wierd problems, with various extension
> defines being set, while the extensions are now part of Mesa's core (and
> so should no longer be defined as extensions).  It looks like Mesa-3.3 needs
> some sanity checking.
 
You need to read the OpenGL ABI for Linux - the new standard that (I hope)
we'll all abide by:

  http://oss.sgi.com/projects/ogl-sample/ABI/

Although I kicked and screamed about this having to be 100% reverse
compatible with older programs - I lost that particular debate.

Hence old programs that use these newer Mesa's that have glext.h
have to define the symbols:

  GL_GLEXT_LEGACY  and GLX_GLXEXT_LEGACY

...before the first inclusion of GL/gl.h - preferably do it on the
compiler command line with '-D'.

Newer programs should abide by the ABI and access extensions though
pointers-to-functions and glGetString using glXGetProcAddressARB - you
should read the ABI document carefully in that case because there are
a couple of subtle 'gotchas' to watch out for.

The ABI is (generally) "A Good Thing" - we should all be using it.


Steve Baker                      (817)619-2657 (Vox/Vox-Mail)
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