Split Rotation.h to Rotation2D.h and RotationBase.h,

and more code factorization based on RotationBase.
Added notes about the main aim of the Translation and Scaling classes.

1 files changed, 134 insertions, 0 deletions

diff --git a/Eigen/src/Geometry/Rotation2D.h b/Eigen/src/Geometry/Rotation2D.h
new file mode 100644
index 000000000..1c3cbc05d
--- /dev/null
+++ b/Eigen/src/Geometry/Rotation2D.h
@@ -0,0 +1,134 @@
+// 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>
+//
+// Eigen is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3 of the License, or (at your option) any later version.
+//
+// Alternatively, you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License and a copy of the GNU General Public License along with
+// Eigen. If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef EIGEN_ROTATION2D_H
+#define EIGEN_ROTATION2D_H
+
+/** \geometry_module \ingroup GeometryModule
+  *
+  * \class Rotation2D
+  *
+  * \brief Represents a rotation/orientation in a 2 dimensional space.
+  *
+  * \param _Scalar the scalar type, i.e., the type of the coefficients
+  *
+  * This class is equivalent to a single scalar representing a counter clock wise rotation
+  * as a single angle in radian. It provides some additional features such as the automatic
+  * conversion from/to a 2x2 rotation matrix. Moreover this class aims to provide a similar
+  * interface to Quaternion in order to facilitate the writing of generic algorithms
+  * dealing with rotations.
+  *
+  * \sa class Quaternion, class Transform
+  */
+template<typename _Scalar> struct ei_traits<Rotation2D<_Scalar> >
+{
+  typedef _Scalar Scalar;
+};
+
+template<typename _Scalar>
+class Rotation2D : public RotationBase<Rotation2D<_Scalar>,2>
+{
+  typedef RotationBase<Rotation2D<_Scalar>,2> Base;
+  using Base::operator*;
+
+public:
+  enum { Dim = 2 };
+  /** the scalar type of the coefficients */
+  typedef _Scalar Scalar;
+  typedef Matrix<Scalar,2,1> Vector2;
+  typedef Matrix<Scalar,2,2> Matrix2;
+
+protected:
+
+  Scalar m_angle;
+
+public:
+
+  /** Construct a 2D counter clock wise rotation from the angle \a a in radian. */
+  inline Rotation2D(Scalar a) : m_angle(a) {}
+
+  /** \returns the rotation angle */
+  inline Scalar angle() const { return m_angle; }
+
+  /** \returns a read-write reference to the rotation angle */
+  inline Scalar& angle() { return m_angle; }
+
+  /** \returns the inverse rotation */
+  inline Rotation2D inverse() const { return -m_angle; }
+
+  /** Concatenates two rotations */
+  inline Rotation2D operator*(const Rotation2D& other) const
+  { return m_angle + other.m_angle; }
+
+  /** Concatenates two rotations */
+  inline Rotation2D& operator*=(const Rotation2D& other)
+  { return m_angle += other.m_angle; }
+
+  /** Applies the rotation to a 2D vector */
+  Vector2 operator* (const Vector2& vec) const
+  { return toRotationMatrix() * vec; }
+
+  template<typename Derived>
+  Rotation2D& fromRotationMatrix(const MatrixBase<Derived>& m);
+  Matrix2 toRotationMatrix(void) const;
+
+  /** \returns the spherical interpolation between \c *this and \a other using
+    * parameter \a t. It is in fact equivalent to a linear interpolation.
+    */
+  inline Rotation2D slerp(Scalar t, const Rotation2D& other) const
+  { return m_angle * (1-t) + other.angle() * t; }
+};
+
+/** \ingroup GeometryModule
+  * single precision 2D rotation type */
+typedef Rotation2D<float> Rotation2Df;
+/** \ingroup GeometryModule
+  * double precision 2D rotation type */
+typedef Rotation2D<double> Rotation2Dd;
+
+/** Set \c *this from a 2x2 rotation matrix \a mat.
+  * In other words, this function extract the rotation angle
+  * from the rotation matrix.
+  */
+template<typename Scalar>
+template<typename Derived>
+Rotation2D<Scalar>& Rotation2D<Scalar>::fromRotationMatrix(const MatrixBase<Derived>& mat)
+{
+  EIGEN_STATIC_ASSERT(Derived::RowsAtCompileTime==2 && Derived::ColsAtCompileTime==2,you_did_a_programming_error);
+  m_angle = ei_atan2(mat.coeff(1,0), mat.coeff(0,0));
+  return *this;
+}
+
+/** Constructs and \returns an equivalent 2x2 rotation matrix.
+  */
+template<typename Scalar>
+typename Rotation2D<Scalar>::Matrix2
+Rotation2D<Scalar>::toRotationMatrix(void) const
+{
+  Scalar sinA = ei_sin(m_angle);
+  Scalar cosA = ei_cos(m_angle);
+  return (Matrix2() << cosA, -sinA, sinA, cosA).finished();
+}
+
+#endif // EIGEN_ROTATION2D_H