Hi Paul, Paul Martz wrote: > Hi folks -- I've noticed that, under some circumstances, > Matrix::getRotate() returns a non-normalized Quat. For example, given > the following code: > > osg::Matrix m( +0.00057735, +0.00000000, +0.00000000, +0.00000000, > +0.00000000, +0.00057735, +0.00000000, +0.00000000, > +0.00000000, +0.00000000, +0.00057735, +0.00000000, > -0.57735026, +1.42264974, -0.57735026, +1.00000000 ) ; > std::cout << m.getRotate() ; > > I get this output: > 0.000000 0.000000 0.000000 0.500433 > > This seems odd because, given the same source > Matrix, Matrix::decompose() returns a normalized rotation Quat (0, 0, 0, > 1). Given that both Quats represent a rotation from the same Matrix, I'd > expect them to be identical. (Mathematically, they are identical, except > the getRotate() return value isn't normalized.) > > Is this a bug that needs to be fixed? I'm not sure if it should be called a bug or missing feature :/
AFAIK, the current getRotate code does not handle cases where the matrix itself is scaled. At some point I made modifications to getRotate to first unscale the matrix, but: 1) It makes it slower for all the "normal" unscaled cases 2) There were other gotchas (e.g. non-uniform scaling and reflection) I did not find a suitable solution. I've never tried decompose, maybe that is the answer. If you look at the code in osgunittests that exercises the getRotate method, I think you'll find some code in there that can test for the scaled matrix case. regards jp > > Paul Martz > *Skew Matrix Software LLC* > http://www.skew-matrix.com <http://www.skew-matrix.com/> > 303 859 9466 > > > > ------------------------------------------------------------------------ > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org -- This message is subject to the CSIR's copyright terms and conditions, e-mail legal notice, and implemented Open Document Format (ODF) standard. The full disclaimer details can be found at http://www.csir.co.za/disclaimer.html. This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. MailScanner thanks Transtec Computers for their support. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
