[Bf-committers] Blender tangent space calculation

[Morten Mikkelsen]

I don't know anything about Python but if you can get hold of the dm
(DerivedMesh)
on the c side of things then I can show you how to get the correct normals
and tangents
and even help you get them welded should you want this.




On Tue, Nov 15, 2011 at 10:43 AM, Eugene Minov <minov.eug at gmail.com> wrote:

> Yes, I absolutely agree, hard faces obviously must be exported in the same
> way how they seen in render.
> I think they can welds along with tangents.
>
> On Tue, Nov 15, 2011 at 9:01 PM, Morten Mikkelsen <mikkelsen7 at gmail.com
> >wrote:
>
> > There is no point in doing this unless you export the correct tangents
> and
> > normals. That is the ones
> > that were used to bake the normal map.
> >
> > I realize it blows that there is no API function to get the render
> normal.
> > So what you have to do is produce it yourself
> > like is done in
> > DerivedMesh.c<
> >
> https://svn.blender.org/svnroot/bf-blender/trunk/blender/source/blender/blenkernel/intern/DerivedMesh.c
> > >
> > and
> > many other places as well.
> > An example in this file is the static function GetNormal() which is used
> as
> >  a call-back function by mikktspace.c
> > and you can see how it uses the averaged normal if the face is set to
> > smooth and it uses
> > the face normal which it calculates itself if the face is set to flat.
> >
> > If you are going to make an api to export tangents I for one cannot
> > emphasize enough
> > that I prefer an all or nothing solution. Either do it right or don't do
> it
> > at all.
> > The last thing we need is to introduce a new tangent space standard
> within
> > blender.
> > Either export the correct basis that was used for baking (this includes
> the
> > normal)
> > or don't try to do it at all.
> > _______________________________________________
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> >
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