But I get in trouble there is no easy way to separate scaling and
(rotation+shear), right? Setting 1s on the diagonal is clearly nonsense,
although that is what we (I) do now.
I wish I could answer, but I have no clear and general solution. For
instance, I browsed OGL doc yesterday and I still don't know if scale
and shear can be done in only one operation using F and glMultMatrixd.
Actually, I don't even understand how the current 4x4 matrix can shear
the box correctly... Do you know a good web page about this?
http://www.songho.ca/opengl/gl_transform.html#matrix doesn't work.
For display, at least, one solution would be to draw the 12 edges one by
one (origin->Hsize[0],origin->Hsize[1],etc.). (note : there is commented
code in periController to recompute Hsize with refSize and F.)
Perhaps list the precise problems here, so we can think about them. For
the most general answer on scaling/rotation split, I would think in
terms of R.U polar
factorisation(http://en.wikipedia.org/wiki/Finite_strain_theory), but
I'm not sure we really need that.
Bruno
--
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Chareyre Bruno
Maître de Conférences
Grenoble INP
Laboratoire 3SR - bureau E145
BP 53 - 38041, Grenoble cedex 9 - France
Tél : 33 4 56 52 86 21
Fax : 33 4 76 82 70 43
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