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      1 // This file is part of Eigen, a lightweight C++ template library
      2 // for linear algebra.
      3 //
      4 // Copyright (C) 2008 Gael Guennebaud <gael.guennebaud (at) inria.fr>
      5 //
      6 // This Source Code Form is subject to the terms of the Mozilla
      7 // Public License v. 2.0. If a copy of the MPL was not distributed
      8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
      9 
     10 #ifndef EIGEN_TRANSLATION_H
     11 #define EIGEN_TRANSLATION_H
     12 
     13 namespace Eigen {
     14 
     15 /** \geometry_module \ingroup Geometry_Module
     16   *
     17   * \class Translation
     18   *
     19   * \brief Represents a translation transformation
     20   *
     21   * \tparam _Scalar the scalar type, i.e., the type of the coefficients.
     22   * \tparam _Dim the  dimension of the space, can be a compile time value or Dynamic
     23   *
     24   * \note This class is not aimed to be used to store a translation transformation,
     25   * but rather to make easier the constructions and updates of Transform objects.
     26   *
     27   * \sa class Scaling, class Transform
     28   */
     29 template<typename _Scalar, int _Dim>
     30 class Translation
     31 {
     32 public:
     33   EIGEN_MAKE_ALIGNED_OPERATOR_NEW_IF_VECTORIZABLE_FIXED_SIZE(_Scalar,_Dim)
     34   /** dimension of the space */
     35   enum { Dim = _Dim };
     36   /** the scalar type of the coefficients */
     37   typedef _Scalar Scalar;
     38   /** corresponding vector type */
     39   typedef Matrix<Scalar,Dim,1> VectorType;
     40   /** corresponding linear transformation matrix type */
     41   typedef Matrix<Scalar,Dim,Dim> LinearMatrixType;
     42   /** corresponding affine transformation type */
     43   typedef Transform<Scalar,Dim,Affine> AffineTransformType;
     44   /** corresponding isometric transformation type */
     45   typedef Transform<Scalar,Dim,Isometry> IsometryTransformType;
     46 
     47 protected:
     48 
     49   VectorType m_coeffs;
     50 
     51 public:
     52 
     53   /** Default constructor without initialization. */
     54   EIGEN_DEVICE_FUNC Translation() {}
     55   /**  */
     56   EIGEN_DEVICE_FUNC inline Translation(const Scalar& sx, const Scalar& sy)
     57   {
     58     eigen_assert(Dim==2);
     59     m_coeffs.x() = sx;
     60     m_coeffs.y() = sy;
     61   }
     62   /**  */
     63   EIGEN_DEVICE_FUNC inline Translation(const Scalar& sx, const Scalar& sy, const Scalar& sz)
     64   {
     65     eigen_assert(Dim==3);
     66     m_coeffs.x() = sx;
     67     m_coeffs.y() = sy;
     68     m_coeffs.z() = sz;
     69   }
     70   /** Constructs and initialize the translation transformation from a vector of translation coefficients */
     71   EIGEN_DEVICE_FUNC explicit inline Translation(const VectorType& vector) : m_coeffs(vector) {}
     72 
     73   /** \brief Retruns the x-translation by value. **/
     74   EIGEN_DEVICE_FUNC inline Scalar x() const { return m_coeffs.x(); }
     75   /** \brief Retruns the y-translation by value. **/
     76   EIGEN_DEVICE_FUNC inline Scalar y() const { return m_coeffs.y(); }
     77   /** \brief Retruns the z-translation by value. **/
     78   EIGEN_DEVICE_FUNC inline Scalar z() const { return m_coeffs.z(); }
     79 
     80   /** \brief Retruns the x-translation as a reference. **/
     81   EIGEN_DEVICE_FUNC inline Scalar& x() { return m_coeffs.x(); }
     82   /** \brief Retruns the y-translation as a reference. **/
     83   EIGEN_DEVICE_FUNC inline Scalar& y() { return m_coeffs.y(); }
     84   /** \brief Retruns the z-translation as a reference. **/
     85   EIGEN_DEVICE_FUNC inline Scalar& z() { return m_coeffs.z(); }
     86 
     87   EIGEN_DEVICE_FUNC const VectorType& vector() const { return m_coeffs; }
     88   EIGEN_DEVICE_FUNC VectorType& vector() { return m_coeffs; }
     89 
     90   EIGEN_DEVICE_FUNC const VectorType& translation() const { return m_coeffs; }
     91   EIGEN_DEVICE_FUNC VectorType& translation() { return m_coeffs; }
     92 
     93   /** Concatenates two translation */
     94   EIGEN_DEVICE_FUNC inline Translation operator* (const Translation& other) const
     95   { return Translation(m_coeffs + other.m_coeffs); }
     96 
     97   /** Concatenates a translation and a uniform scaling */
     98   EIGEN_DEVICE_FUNC inline AffineTransformType operator* (const UniformScaling<Scalar>& other) const;
     99 
    100   /** Concatenates a translation and a linear transformation */
    101   template<typename OtherDerived>
    102   EIGEN_DEVICE_FUNC inline AffineTransformType operator* (const EigenBase<OtherDerived>& linear) const;
    103 
    104   /** Concatenates a translation and a rotation */
    105   template<typename Derived>
    106   EIGEN_DEVICE_FUNC inline IsometryTransformType operator*(const RotationBase<Derived,Dim>& r) const
    107   { return *this * IsometryTransformType(r); }
    108 
    109   /** \returns the concatenation of a linear transformation \a l with the translation \a t */
    110   // its a nightmare to define a templated friend function outside its declaration
    111   template<typename OtherDerived> friend
    112   EIGEN_DEVICE_FUNC inline AffineTransformType operator*(const EigenBase<OtherDerived>& linear, const Translation& t)
    113   {
    114     AffineTransformType res;
    115     res.matrix().setZero();
    116     res.linear() = linear.derived();
    117     res.translation() = linear.derived() * t.m_coeffs;
    118     res.matrix().row(Dim).setZero();
    119     res(Dim,Dim) = Scalar(1);
    120     return res;
    121   }
    122 
    123   /** Concatenates a translation and a transformation */
    124   template<int Mode, int Options>
    125   EIGEN_DEVICE_FUNC inline Transform<Scalar,Dim,Mode> operator* (const Transform<Scalar,Dim,Mode,Options>& t) const
    126   {
    127     Transform<Scalar,Dim,Mode> res = t;
    128     res.pretranslate(m_coeffs);
    129     return res;
    130   }
    131 
    132   /** Applies translation to vector */
    133   template<typename Derived>
    134   inline typename internal::enable_if<Derived::IsVectorAtCompileTime,VectorType>::type
    135   operator* (const MatrixBase<Derived>& vec) const
    136   { return m_coeffs + vec.derived(); }
    137 
    138   /** \returns the inverse translation (opposite) */
    139   Translation inverse() const { return Translation(-m_coeffs); }
    140 
    141   Translation& operator=(const Translation& other)
    142   {
    143     m_coeffs = other.m_coeffs;
    144     return *this;
    145   }
    146 
    147   static const Translation Identity() { return Translation(VectorType::Zero()); }
    148 
    149   /** \returns \c *this with scalar type casted to \a NewScalarType
    150     *
    151     * Note that if \a NewScalarType is equal to the current scalar type of \c *this
    152     * then this function smartly returns a const reference to \c *this.
    153     */
    154   template<typename NewScalarType>
    155   EIGEN_DEVICE_FUNC inline typename internal::cast_return_type<Translation,Translation<NewScalarType,Dim> >::type cast() const
    156   { return typename internal::cast_return_type<Translation,Translation<NewScalarType,Dim> >::type(*this); }
    157 
    158   /** Copy constructor with scalar type conversion */
    159   template<typename OtherScalarType>
    160   EIGEN_DEVICE_FUNC inline explicit Translation(const Translation<OtherScalarType,Dim>& other)
    161   { m_coeffs = other.vector().template cast<Scalar>(); }
    162 
    163   /** \returns \c true if \c *this is approximately equal to \a other, within the precision
    164     * determined by \a prec.
    165     *
    166     * \sa MatrixBase::isApprox() */
    167   EIGEN_DEVICE_FUNC bool isApprox(const Translation& other, const typename NumTraits<Scalar>::Real& prec = NumTraits<Scalar>::dummy_precision()) const
    168   { return m_coeffs.isApprox(other.m_coeffs, prec); }
    169 
    170 };
    171 
    172 /** \addtogroup Geometry_Module */
    173 //@{
    174 typedef Translation<float, 2> Translation2f;
    175 typedef Translation<double,2> Translation2d;
    176 typedef Translation<float, 3> Translation3f;
    177 typedef Translation<double,3> Translation3d;
    178 //@}
    179 
    180 template<typename Scalar, int Dim>
    181 EIGEN_DEVICE_FUNC inline typename Translation<Scalar,Dim>::AffineTransformType
    182 Translation<Scalar,Dim>::operator* (const UniformScaling<Scalar>& other) const
    183 {
    184   AffineTransformType res;
    185   res.matrix().setZero();
    186   res.linear().diagonal().fill(other.factor());
    187   res.translation() = m_coeffs;
    188   res(Dim,Dim) = Scalar(1);
    189   return res;
    190 }
    191 
    192 template<typename Scalar, int Dim>
    193 template<typename OtherDerived>
    194 EIGEN_DEVICE_FUNC inline typename Translation<Scalar,Dim>::AffineTransformType
    195 Translation<Scalar,Dim>::operator* (const EigenBase<OtherDerived>& linear) const
    196 {
    197   AffineTransformType res;
    198   res.matrix().setZero();
    199   res.linear() = linear.derived();
    200   res.translation() = m_coeffs;
    201   res.matrix().row(Dim).setZero();
    202   res(Dim,Dim) = Scalar(1);
    203   return res;
    204 }
    205 
    206 } // end namespace Eigen
    207 
    208 #endif // EIGEN_TRANSLATION_H
    209