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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// no include guard, we'll include this twice from All.h from Eigen2Support, and it's internal anyway
namespace Eigen {
template<typename Other,
int OtherRows=Other::RowsAtCompileTime,
int OtherCols=Other::ColsAtCompileTime>
struct ei_quaternion_assign_impl;
/** \geometry_module \ingroup Geometry_Module
*
* \class Quaternion
*
* \brief The quaternion class used to represent 3D orientations and rotations
*
* \param _Scalar the scalar type, i.e., the type of the coefficients
*
* This class represents a quaternion \f$ w+xi+yj+zk \f$ that is a convenient representation of
* orientations and rotations of objects in three dimensions. Compared to other representations
* like Euler angles or 3x3 matrices, quatertions offer the following advantages:
* \li \b compact storage (4 scalars)
* \li \b efficient to compose (28 flops),
* \li \b stable spherical interpolation
*
* The following two typedefs are provided for convenience:
* \li \c Quaternionf for \c float
* \li \c Quaterniond for \c double
*
* \sa class AngleAxis, class Transform
*/
template<typename _Scalar> struct ei_traits<Quaternion<_Scalar> >
{
typedef _Scalar Scalar;
};
template<typename _Scalar>
class Quaternion : public RotationBase<Quaternion<_Scalar>,3>
{
typedef RotationBase<Quaternion<_Scalar>,3> Base;
public:
EIGEN_MAKE_ALIGNED_OPERATOR_NEW_IF_VECTORIZABLE_FIXED_SIZE(_Scalar,4)
using Base::operator*;
/** the scalar type of the coefficients */
typedef _Scalar Scalar;
/** the type of the Coefficients 4-vector */
typedef Matrix<Scalar, 4, 1> Coefficients;
/** the type of a 3D vector */
typedef Matrix<Scalar,3,1> Vector3;
/** the equivalent rotation matrix type */
typedef Matrix<Scalar,3,3> Matrix3;
/** the equivalent angle-axis type */
typedef AngleAxis<Scalar> AngleAxisType;
/** \returns the \c x coefficient */
inline Scalar x() const { return m_coeffs.coeff(0); }
/** \returns the \c y coefficient */
inline Scalar y() const { return m_coeffs.coeff(1); }
/** \returns the \c z coefficient */
inline Scalar z() const { return m_coeffs.coeff(2); }
/** \returns the \c w coefficient */
inline Scalar w() const { return m_coeffs.coeff(3); }
/** \returns a reference to the \c x coefficient */
inline Scalar& x() { return m_coeffs.coeffRef(0); }
/** \returns a reference to the \c y coefficient */
inline Scalar& y() { return m_coeffs.coeffRef(1); }
/** \returns a reference to the \c z coefficient */
inline Scalar& z() { return m_coeffs.coeffRef(2); }
/** \returns a reference to the \c w coefficient */
inline Scalar& w() { return m_coeffs.coeffRef(3); }
/** \returns a read-only vector expression of the imaginary part (x,y,z) */
inline const Block<const Coefficients,3,1> vec() const { return m_coeffs.template start<3>(); }
/** \returns a vector expression of the imaginary part (x,y,z) */
inline Block<Coefficients,3,1> vec() { return m_coeffs.template start<3>(); }
/** \returns a read-only vector expression of the coefficients (x,y,z,w) */
inline const Coefficients& coeffs() const { return m_coeffs; }
/** \returns a vector expression of the coefficients (x,y,z,w) */
inline Coefficients& coeffs() { return m_coeffs; }
/** Default constructor leaving the quaternion uninitialized. */
inline Quaternion() {}
/** Constructs and initializes the quaternion \f$ w+xi+yj+zk \f$ from
* its four coefficients \a w, \a x, \a y and \a z.
*
* \warning Note the order of the arguments: the real \a w coefficient first,
* while internally the coefficients are stored in the following order:
* [\c x, \c y, \c z, \c w]
*/
inline Quaternion(Scalar w, Scalar x, Scalar y, Scalar z)
{ m_coeffs << x, y, z, w; }
/** Copy constructor */
inline Quaternion(const Quaternion& other) { m_coeffs = other.m_coeffs; }
/** Constructs and initializes a quaternion from the angle-axis \a aa */
explicit inline Quaternion(const AngleAxisType& aa) { *this = aa; }
/** Constructs and initializes a quaternion from either:
* - a rotation matrix expression,
* - a 4D vector expression representing quaternion coefficients.
* \sa operator=(MatrixBase<Derived>)
*/
template<typename Derived>
explicit inline Quaternion(const MatrixBase<Derived>& other) { *this = other; }
Quaternion& operator=(const Quaternion& other);
Quaternion& operator=(const AngleAxisType& aa);
template<typename Derived>
Quaternion& operator=(const MatrixBase<Derived>& m);
/** \returns a quaternion representing an identity rotation
* \sa MatrixBase::Identity()
*/
static inline Quaternion Identity() { return Quaternion(1, 0, 0, 0); }
/** \sa Quaternion::Identity(), MatrixBase::setIdentity()
*/
inline Quaternion& setIdentity() { m_coeffs << 0, 0, 0, 1; return *this; }
/** \returns the squared norm of the quaternion's coefficients
* \sa Quaternion::norm(), MatrixBase::squaredNorm()
*/
inline Scalar squaredNorm() const { return m_coeffs.squaredNorm(); }
/** \returns the norm of the quaternion's coefficients
* \sa Quaternion::squaredNorm(), MatrixBase::norm()
*/
inline Scalar norm() const { return m_coeffs.norm(); }
/** Normalizes the quaternion \c *this
* \sa normalized(), MatrixBase::normalize() */
inline void normalize() { m_coeffs.normalize(); }
/** \returns a normalized version of \c *this
* \sa normalize(), MatrixBase::normalized() */
inline Quaternion normalized() const { return Quaternion(m_coeffs.normalized()); }
/** \returns the dot product of \c *this and \a other
* Geometrically speaking, the dot product of two unit quaternions
* corresponds to the cosine of half the angle between the two rotations.
* \sa angularDistance()
*/
inline Scalar eigen2_dot(const Quaternion& other) const { return m_coeffs.eigen2_dot(other.m_coeffs); }
inline Scalar angularDistance(const Quaternion& other) const;
Matrix3 toRotationMatrix(void) const;
template<typename Derived1, typename Derived2>
Quaternion& setFromTwoVectors(const MatrixBase<Derived1>& a, const MatrixBase<Derived2>& b);
inline Quaternion operator* (const Quaternion& q) const;
inline Quaternion& operator*= (const Quaternion& q);
Quaternion inverse(void) const;
Quaternion conjugate(void) const;
Quaternion slerp(Scalar t, const Quaternion& other) const;
template<typename Derived>
Vector3 operator* (const MatrixBase<Derived>& vec) const;
/** \returns \c *this with scalar type casted to \a NewScalarType
*
* Note that if \a NewScalarType is equal to the current scalar type of \c *this
* then this function smartly returns a const reference to \c *this.
*/
template<typename NewScalarType>
inline typename internal::cast_return_type<Quaternion,Quaternion<NewScalarType> >::type cast() const
{ return typename internal::cast_return_type<Quaternion,Quaternion<NewScalarType> >::type(*this); }
/** Copy constructor with scalar type conversion */
template<typename OtherScalarType>
inline explicit Quaternion(const Quaternion<OtherScalarType>& other)
{ m_coeffs = other.coeffs().template cast<Scalar>(); }
/** \returns \c true if \c *this is approximately equal to \a other, within the precision
* determined by \a prec.
*
* \sa MatrixBase::isApprox() */
bool isApprox(const Quaternion& other, typename NumTraits<Scalar>::Real prec = precision<Scalar>()) const
{ return m_coeffs.isApprox(other.m_coeffs, prec); }
protected:
Coefficients m_coeffs;
};
/** \ingroup Geometry_Module
* single precision quaternion type */
typedef Quaternion<float> Quaternionf;
/** \ingroup Geometry_Module
* double precision quaternion type */
typedef Quaternion<double> Quaterniond;
// Generic Quaternion * Quaternion product
template<typename Scalar> inline Quaternion<Scalar>
ei_quaternion_product(const Quaternion<Scalar>& a, const Quaternion<Scalar>& b)
{
return Quaternion<Scalar>
(
a.w() * b.w() - a.x() * b.x() - a.y() * b.y() - a.z() * b.z(),
a.w() * b.x() + a.x() * b.w() + a.y() * b.z() - a.z() * b.y(),
a.w() * b.y() + a.y() * b.w() + a.z() * b.x() - a.x() * b.z(),
a.w() * b.z() + a.z() * b.w() + a.x() * b.y() - a.y() * b.x()
);
}
/** \returns the concatenation of two rotations as a quaternion-quaternion product */
template <typename Scalar>
inline Quaternion<Scalar> Quaternion<Scalar>::operator* (const Quaternion& other) const
{
return ei_quaternion_product(*this,other);
}
/** \sa operator*(Quaternion) */
template <typename Scalar>
inline Quaternion<Scalar>& Quaternion<Scalar>::operator*= (const Quaternion& other)
{
return (*this = *this * other);
}
/** Rotation of a vector by a quaternion.
* \remarks If the quaternion is used to rotate several points (>1)
* then it is much more efficient to first convert it to a 3x3 Matrix.
* Comparison of the operation cost for n transformations:
* - Quaternion: 30n
* - Via a Matrix3: 24 + 15n
*/
template <typename Scalar>
template<typename Derived>
inline typename Quaternion<Scalar>::Vector3
Quaternion<Scalar>::operator* (const MatrixBase<Derived>& v) const
{
// Note that this algorithm comes from the optimization by hand
// of the conversion to a Matrix followed by a Matrix/Vector product.
// It appears to be much faster than the common algorithm found
// in the litterature (30 versus 39 flops). It also requires two
// Vector3 as temporaries.
Vector3 uv;
uv = 2 * this->vec().cross(v);
return v + this->w() * uv + this->vec().cross(uv);
}
template<typename Scalar>
inline Quaternion<Scalar>& Quaternion<Scalar>::operator=(const Quaternion& other)
{
m_coeffs = other.m_coeffs;
return *this;
}
/** Set \c *this from an angle-axis \a aa and returns a reference to \c *this
*/
template<typename Scalar>
inline Quaternion<Scalar>& Quaternion<Scalar>::operator=(const AngleAxisType& aa)
{
Scalar ha = Scalar(0.5)*aa.angle(); // Scalar(0.5) to suppress precision loss warnings
this->w() = ei_cos(ha);
this->vec() = ei_sin(ha) * aa.axis();
return *this;
}
/** Set \c *this from the expression \a xpr:
* - if \a xpr is a 4x1 vector, then \a xpr is assumed to be a quaternion
* - if \a xpr is a 3x3 matrix, then \a xpr is assumed to be rotation matrix
* and \a xpr is converted to a quaternion
*/
template<typename Scalar>
template<typename Derived>
inline Quaternion<Scalar>& Quaternion<Scalar>::operator=(const MatrixBase<Derived>& xpr)
{
ei_quaternion_assign_impl<Derived>::run(*this, xpr.derived());
return *this;
}
/** Convert the quaternion to a 3x3 rotation matrix */
template<typename Scalar>
inline typename Quaternion<Scalar>::Matrix3
Quaternion<Scalar>::toRotationMatrix(void) const
{
// NOTE if inlined, then gcc 4.2 and 4.4 get rid of the temporary (not gcc 4.3 !!)
// if not inlined then the cost of the return by value is huge ~ +35%,
// however, not inlining this function is an order of magnitude slower, so
// it has to be inlined, and so the return by value is not an issue
Matrix3 res;
const Scalar tx = Scalar(2)*this->x();
const Scalar ty = Scalar(2)*this->y();
const Scalar tz = Scalar(2)*this->z();
const Scalar twx = tx*this->w();
const Scalar twy = ty*this->w();
const Scalar twz = tz*this->w();
const Scalar txx = tx*this->x();
const Scalar txy = ty*this->x();
const Scalar txz = tz*this->x();
const Scalar tyy = ty*this->y();
const Scalar tyz = tz*this->y();
const Scalar tzz = tz*this->z();
res.coeffRef(0,0) = Scalar(1)-(tyy+tzz);
res.coeffRef(0,1) = txy-twz;
res.coeffRef(0,2) = txz+twy;
res.coeffRef(1,0) = txy+twz;
res.coeffRef(1,1) = Scalar(1)-(txx+tzz);
res.coeffRef(1,2) = tyz-twx;
res.coeffRef(2,0) = txz-twy;
res.coeffRef(2,1) = tyz+twx;
res.coeffRef(2,2) = Scalar(1)-(txx+tyy);
return res;
}
/** Sets *this to be a quaternion representing a rotation sending the vector \a a to the vector \a b.
*
* \returns a reference to *this.
*
* Note that the two input vectors do \b not have to be normalized.
*/
template<typename Scalar>
template<typename Derived1, typename Derived2>
inline Quaternion<Scalar>& Quaternion<Scalar>::setFromTwoVectors(const MatrixBase<Derived1>& a, const MatrixBase<Derived2>& b)
{
Vector3 v0 = a.normalized();
Vector3 v1 = b.normalized();
Scalar c = v0.eigen2_dot(v1);
// if dot == 1, vectors are the same
if (ei_isApprox(c,Scalar(1)))
{
// set to identity
this->w() = 1; this->vec().setZero();
return *this;
}
// if dot == -1, vectors are opposites
if (ei_isApprox(c,Scalar(-1)))
{
this->vec() = v0.unitOrthogonal();
this->w() = 0;
return *this;
}
Vector3 axis = v0.cross(v1);
Scalar s = ei_sqrt((Scalar(1)+c)*Scalar(2));
Scalar invs = Scalar(1)/s;
this->vec() = axis * invs;
this->w() = s * Scalar(0.5);
return *this;
}
/** \returns the multiplicative inverse of \c *this
* Note that in most cases, i.e., if you simply want the opposite rotation,
* and/or the quaternion is normalized, then it is enough to use the conjugate.
*
* \sa Quaternion::conjugate()
*/
template <typename Scalar>
inline Quaternion<Scalar> Quaternion<Scalar>::inverse() const
{
// FIXME should this function be called multiplicativeInverse and conjugate() be called inverse() or opposite() ??
Scalar n2 = this->squaredNorm();
if (n2 > 0)
return Quaternion(conjugate().coeffs() / n2);
else
{
// return an invalid result to flag the error
return Quaternion(Coefficients::Zero());
}
}
/** \returns the conjugate of the \c *this which is equal to the multiplicative inverse
* if the quaternion is normalized.
* The conjugate of a quaternion represents the opposite rotation.
*
* \sa Quaternion::inverse()
*/
template <typename Scalar>
inline Quaternion<Scalar> Quaternion<Scalar>::conjugate() const
{
return Quaternion(this->w(),-this->x(),-this->y(),-this->z());
}
/** \returns the angle (in radian) between two rotations
* \sa eigen2_dot()
*/
template <typename Scalar>
inline Scalar Quaternion<Scalar>::angularDistance(const Quaternion& other) const
{
double d = ei_abs(this->eigen2_dot(other));
if (d>=1.0)
return 0;
return Scalar(2) * std::acos(d);
}
/** \returns the spherical linear interpolation between the two quaternions
* \c *this and \a other at the parameter \a t
*/
template <typename Scalar>
Quaternion<Scalar> Quaternion<Scalar>::slerp(Scalar t, const Quaternion& other) const
{
static const Scalar one = Scalar(1) - machine_epsilon<Scalar>();
Scalar d = this->eigen2_dot(other);
Scalar absD = ei_abs(d);
Scalar scale0;
Scalar scale1;
if (absD>=one)
{
scale0 = Scalar(1) - t;
scale1 = t;
}
else
{
// theta is the angle between the 2 quaternions
Scalar theta = std::acos(absD);
Scalar sinTheta = ei_sin(theta);
scale0 = ei_sin( ( Scalar(1) - t ) * theta) / sinTheta;
scale1 = ei_sin( ( t * theta) ) / sinTheta;
if (d<0)
scale1 = -scale1;
}
return Quaternion<Scalar>(scale0 * coeffs() + scale1 * other.coeffs());
}
// set from a rotation matrix
template<typename Other>
struct ei_quaternion_assign_impl<Other,3,3>
{
typedef typename Other::Scalar Scalar;
static inline void run(Quaternion<Scalar>& q, const Other& mat)
{
// This algorithm comes from "Quaternion Calculus and Fast Animation",
// Ken Shoemake, 1987 SIGGRAPH course notes
Scalar t = mat.trace();
if (t > 0)
{
t = ei_sqrt(t + Scalar(1.0));
q.w() = Scalar(0.5)*t;
t = Scalar(0.5)/t;
q.x() = (mat.coeff(2,1) - mat.coeff(1,2)) * t;
q.y() = (mat.coeff(0,2) - mat.coeff(2,0)) * t;
q.z() = (mat.coeff(1,0) - mat.coeff(0,1)) * t;
}
else
{
int i = 0;
if (mat.coeff(1,1) > mat.coeff(0,0))
i = 1;
if (mat.coeff(2,2) > mat.coeff(i,i))
i = 2;
int j = (i+1)%3;
int k = (j+1)%3;
t = ei_sqrt(mat.coeff(i,i)-mat.coeff(j,j)-mat.coeff(k,k) + Scalar(1.0));
q.coeffs().coeffRef(i) = Scalar(0.5) * t;
t = Scalar(0.5)/t;
q.w() = (mat.coeff(k,j)-mat.coeff(j,k))*t;
q.coeffs().coeffRef(j) = (mat.coeff(j,i)+mat.coeff(i,j))*t;
q.coeffs().coeffRef(k) = (mat.coeff(k,i)+mat.coeff(i,k))*t;
}
}
};
// set from a vector of coefficients assumed to be a quaternion
template<typename Other>
struct ei_quaternion_assign_impl<Other,4,1>
{
typedef typename Other::Scalar Scalar;
static inline void run(Quaternion<Scalar>& q, const Other& vec)
{
q.coeffs() = vec;
}
};
} // end namespace Eigen