Re: [ggt-devel] rotating a vector with an axisangle

[subatomic <ke...@su...>]

it's possible this func isn't implemented yet...  if you create an
implementation, send it along...

It's also possible that the implementation was omitted since it could lull
people into writing inefficient code...
i.e. you'd need to encode that axis angle into something to xform the vector
by anyway.


an example function you could write...

/// pseudo code for axisangle * vec...
vec operator*(AA, Vec)
{
   convert( quat, aa )   //< ( i haven't checked, but I think this one
exists...)
   return quat * vec;
}


On 9/23/06, subatomic <ke...@su...> wrote:
>
>
> try reversing the order?
>
> On 9/23/06, Stuart Tett <st...@vi...> wrote:
> >
> > I got this from the GMTL FAQ:
> >
> > gmtl::Vec3f myVec;
> > gmtl::AxisAngle myAA;
> > gmtl::Quaternion myQuat;
> >
> > myVec = myVec * myAA;
> > myVec = myVec * myQuat;
> >
> > I first tried it with an gmtl::AxisAnglef, then a gmtl::Quatf. Neither
> > seem to have an operator* for multiplying a Vec by an AxisAngle
> >
> > I grep'd the src code to make sure. The only operator's I found were
> > for:
> >
> > VecBase<DATA_TYPE, 3> operator*( const Quat<DATA_TYPE>& rot, const
> > VecBase<DATA_TYPE, 3>& vector )
> >
> > VecBase<DATA_TYPE, 3> operator*=(VecBase<DATA_TYPE, 3>& vector, const
> > Quat<DATA_TYPE>& rot)
> >
> > so you could do myVec = myQuat * myVec;
> >
> > But how could I rotate a vector by a AxisAngle? Do I just have to
> > convert it to a quaternion?
> >
> > Basically, I want to rotate a particle theta degrees around an arbitrary
> > axis.
> >
> > Thanks.
> > Stuart
> >
> >
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>
>
> --
> Kevin Meinert
> http://www.subatomicglue.com




-- 
Kevin Meinert
http://www.subatomicglue.com