[Bf-committers] possible quaternion bug
Ton Roosendaal
bf-committers@blender.org
Fri, 28 Mar 2003 11:42:01 +0100
Hi Heikki,
Yes, you are right, the 'qw' part is in quat[0] in Blender. The
QuatToSpher() function looks very confusing to me... it doesn't seem to
be in use in Blender though.
-Ton-
On Wednesday, Mar 26, 2003, at 21:14 Europe/Amsterdam, Heikki Orsila
wrote:
> I am not very familiar with quaternions, but blenlib/intern/arithb.c :
> void QuatToSpher() looks odd comparing to VecRotToQuat().
>
> QuatToSpher() has:
> qx = quat[0];
> qy = quat[1];
> qz = quat[2];
> qw = quat[3];
> cos_theta = qw;
>
> VecRotToQuat() has:
> quat[1]= vec[0];
> quat[2]= vec[1];
> quat[3]= vec[2];
> ...
> quat[0]= (float)cos( phi/2.0 );
>
> Does blender use contradictory internal formats with quaternions?
>
> The function QuatToSpher() has a comment that it might not work 100%.
> Could the problem be fixed by just doing:
>
> qx = quat[1];
> qy = quat[2];
> qz = quat[3];
> qw = quat[0];
>
> Haven't tested this. Just a suspicion.
>
> Heikki Orsila There has yet to be any innovation, new
> heikki.orsila@ee.tut.fi features or new capabilities out of the
> http://ee.tut.fi/~heikki Linux platform. - Steve Ballmer of Microsoft
>
> _______________________________________________
> Bf-committers mailing list
> Bf-committers@blender.org
> http://www.blender.org/mailman/listinfo/bf-committers
>
>
------------------------------------------------------------------------
--
Ton Roosendaal Blender Foundation ton@blender.org