Re: libGL and libOSMesa dispatch conflict issue on Fedora 14 build

On October 5, 2011 12:24:49 tom fogal wrote:
> You need to mangle OSMesa.
> 
> Mangled Mesa support is currently broken in VTK.  You might want to
> follow my posts to the vtk-developers list; my group has fixed this
> support (among other things) in a branch of 5.8.

Thanks Tom.

I've read through the last year of your posts to the vtk-developer list.  
Here's a link (for anyone else following the discussion) to your last one 
summarizing your current position

http://www.vtk.org/pipermail/vtk-developers/2011-August/010250.html

I also read around a bit about mangled OSMesa.  From what I can see

1 - The Fedora libGL is not compiled with --enable-gl-osmesa and so does not 
provide the OSMesa* functions.
2 - The Fedora libOSMesa is not compiled with USE_MGL_NAMESPACE.

My understanding is then that the former implies the only way to get OSMesa 
functionality is to compile up a seperated mangled OSMesa library, while the 
later implies that this isn't libOSMesa as it wasn't compiled that way.

All together this means the Fedora VTK packaging is buggy as compiled as it 
sets VTK_OPENGL_HAS_OSMESA on and VTK_USE_MANGLED_MESA off.  It also means that 
the only ways to enable OSMesa would be

1 - Get your patches, build a custom mangled OSMesa, and compile against it 
using VTK_OPENGL_HAS_OSMESA off and VTK_USE_MANGLED_MESA on.
2 - Recompile libGL to support OSMesa using --enable-gl-osmesa and compile 
against it using using VTK_OPENGL_HAS_OSMESA on and VTK_USE_MANGLED_MESA off.

Thanks!  -Tyson

PS:  BTW, Good to hear VisIt is getting an update to the latest VTK too.