2D vector to Quaternion

Question

I have a 2D vector (with only X and Y), and my engine only supports orientation through Quaternions.

How do I translate a 2D vector to a quaternion?

The X and Y represent the direction (so X = 0 and Y=1 means going forward, X=0.707 and Y=0.707 means rotate 45 degree, etc).

What library is it? Are you sure it doesn't have any interchange methods? — Seth Battin, Commented Jul 29, 2013 at 21:07

Seth Battin · Accepted Answer · 2013-07-29 21:20:16Z

2

void Ogre::Quaternion::FromAngleAxis(
    const Radian & rfAngle, const Vector3 & rkAxis )

Your rkAxis will always be UnitZ, because you are constraining yourself to the X-Y plane.

answered Jul 29, 2013 at 21:20

Seth Battin

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\$\begingroup\$ and the angle? How do I find it? \$\endgroup\$
– Pacha
Commented Jul 29, 2013 at 21:20
\$\begingroup\$ It's the angle of rotation, and it is arbitrary. \$\endgroup\$
– Seth Battin
Commented Jul 29, 2013 at 21:22
\$\begingroup\$ But how do I find the angle from a 2D vector? \$\endgroup\$
– Pacha
Commented Jul 29, 2013 at 21:23
\$\begingroup\$ You have some options there, but it will probably involve arctangent \$\endgroup\$
– Seth Battin
Commented Jul 29, 2013 at 21:25
\$\begingroup\$ it is better to store the rotation/orientation and calculate the direction from it if possible \$\endgroup\$
– Quonux
Commented Jul 29, 2013 at 22:49

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