Hi, am I using this formula correct?
I want to use quaternions for rotation to avoid jimbolo effect:
[...]
Quat q(x, y, z, w);
Matrix3 mat_knots_rotation;
mat_knots_rotation.SetRotate(q);
mat_knots_rotation.TransformPoints(.. my vertex bufers..)
[...]
Well its actually works, the mesh is rotating, but I am confused about values that should I use for creating Quat q. for example if I am increasing ‘w’ value from 0 to 20, the mesh rotates but slows down and stops…
the x,y,z makes a vector, should I put thees numbers already normalized? what values can by put as ‘w’. Its a degree of rotation but should I convert degrees to radians first?
Should I also use q.Normalize() for some reason? or when?
Thanks in advance!
hmm… I found more informatin and used this formula for x,y,z and w
x = RotationAxis.x * sin(RotationAngle / 2)
y = RotationAxis.y * sin(RotationAngle / 2)
z = RotationAxis.z * sin(RotationAngle / 2)
w = cos(RotationAngle / 2)
and so in the code:
[...]
float rot_angle = DEG_TO_RAD(w) / 2.0f;
float sin_rot_angle = sinf(rot_angle);
Quat q(x * sin_rot_angle, y * sin_rot_angle, z * sin_rot_angle, cosf(rot_angle));
Matrix3 mat_knots_rotation(1);
mat_knots_rotation.SetRotate(q);
[...]
I think it works now… its a pity that they didn’t mention about it in the sdk reference …
there would be no need as they already provide
Quat& Quat::SetEuler ( float X, float Y, float Z )
and
Quat & Quat::Set (const AngAxis &aa)
also you can circumvent Quat altogether and use
void Matrix3::SetAngleAxis ( const Point3 & axis, float angle )
Thanks Klvnk!