Re: [Vxl-users] Mesa link problems with Redhat and VGUI

[Amitha P. <pe...@cs...>]

On Thu 12 Jun 2003, Pete Woodward Woodward wrote:
> I'm having a problem with the linked vgui library on linux (RH7.3)
> 
> I've installed later versions of mesa on the OS. The library versions are
> MESA 4.0
> O GL 1.4
> O GL UTILS 1.3
> 
> The link failed for some of the examples due to the unresolved routines:-
> XMesaGetBackBuffer/XMesaGetCurrentBuffer in the vgui library.

You have both Mesa and (some other) OpenGL on your system? If this is
the case, you have to be very careful that the include files used and
the libraries linked against are from the same set. (That is, Mesa
includes with the Mesa libraries, *or* system includes with the system
libraries.)

> I saw the earlier postings that suggested added an additional cmake
> construction which essentially set VGU_MESA to one or zero. This I *did*
> do, by adding into the vgui/cmakelist.txt control file just before the 
> main
> targets, as mentioned
> 
> This seems to have some effect 'cos the flag is indeed set on the
> generated makefile (it gets set to one, i.e. -DVGUI_MESA=1). But the
> link problem persists on the example code in vgui/examples/...
> 
> Is there a fix for this, and/or and explanation because the routines 
> mentioned are certainly compiled into the Mesa library....

The routines are an undocumented, Mesa-specific backdoor routines to
speed up rendering. If VGUI_MESA is set to 1, then you *must* link
against the Mesa libraries.

If, as I suspect, you have both Mesa and a system GL, the easiest
solution will be to rename the Mesa libraries to libMesaGL and
libMesaGLU, and specify these as your OpenGL libraries in the
CMakeCache.txt.

> 
> The other salient details are:-
> 
> gcc version 2.96
> rh version 7.3
> vcl v 1.0 beta 2 fix1

Ooops. Just noticed that you are using beta 2, not cvs. The above
*may* apply. Beta 2 is quite old. We (the developers) have been
discussing more frequent updates, but...

Amitha.