/// <summary>
/// Creates a <see cref="Quaternion"/> that rotates one <see cref="Vector3D"/> onto another. A rotation axis must be supplied if <see cref="Vector3D"> Vector3Ds </see> are antiparallel.
/// </summary>
/// <param name="v1">The first <see cref="Vector3D"/>.</param>
/// <param name="v2">The second <see cref="Vector3D"/>.</param>
/// <param name="axis">Axis that will be rotated around if <see cref="Vector3D">Vector3Ds</see> are antiparallel.</param>
/// <returns>A rotation <see cref="Quaternion"/>.</returns>
public static Quaternion QuaternionRotateBetweenVectors(Vector3D v1, Vector3D v2, Vector3D?axis = null)
{
if (v1.ApproxEquals(v2, 1E-6f))
{
return(Quaternion.Identity);
}
axis ??= Vector3D.UnitY;
Vector3D rotationAxis = v1.ApproxEquals(-v2, 1E-6F) ? (Vector3D)axis : v1.CrossProduct(v2).Normalise();
float angle = v1.Angle(v2);
return(QuaternionRotate(rotationAxis, angle));
}
private static void VectorCheck(Vector3D firstVector, Vector3D secondVector)
{
if (firstVector.ApproxEquals(Vector3D.Zero, 1E-6f) || secondVector.ApproxEquals(Vector3D.Zero, 1E-6f))
{
throw new ArgumentException("New direction vector(s) cannot be set to zero vector.");
}
}