Re: [Mesa3d-dev] GL_EXT_vertex_weighting (was EXT_texture_env discussion)

[Brian P. <br...@pr...>]

Olivier Michel wrote:
> 
> Hello,
> 
> I found two serious bugs in the GLU tesselator. I reported these bugs on
> the sourceforge bug tracking system. They are easy to reproduce on linux
> using gtklookat-0.8.2 (which uses libvrml97-0.8.2) and loading the two
> VRML files I mention in the bug report.
> 
> I tested these two VRML files on my G3 with MacLookAt which relies on
> the same libvrml97 library but uses Apple OpenGL and they both worked
> nicely.
> 
> Both gtklookat and libvrml97 (as well as MacLookAt) are available from
> http://www.openvrml.org/projects/ with complete source code.
> 
> One bug is very annoying since it makes GLU crash (SEGFAULT probably due
> to a memory leak while attempting to free memory). The other bug causes
> reversing the order of vertices in some non convex faces when the normal
> is negative, which makes that the wrong side of the face is rendered
> (typically the top face of a non-convex VRML Extrusion is drawn properly
> while the bottom face is drawn on the wrong side).
> 
> I tryed to get into the GLU code to understand the problem, but it seems
> not so easy for me. I think you Gareth are the author of that code and
> you may help me fixing that problem if you can reproduce the bug (any
> hint greatly appreciated).

I suggest building/using SGI's GLU library from the SI release.

-Brian