Rotation2D.h

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.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/.
// SPDX-License-Identifier: MPL-2.0
 
#ifndef EIGEN_ROTATION2D_H
#define EIGEN_ROTATION2D_H
 
// IWYU pragma: private
#include "./InternalHeaderCheck.h"
 
namespace Eigen {

 
namespace internal {
 
template <typename Scalar_>
struct traits<Rotation2D<Scalar_> > {
  using Scalar = Scalar_;
};
}  // end namespace internal
 
template <typename Scalar_>
class Rotation2D : public RotationBase<Rotation2D<Scalar_>, 2> {
  using Base = RotationBase<Rotation2D<Scalar_>, 2>;
 
 public:
  using Base::operator*;
 
  enum { Dim = 2 };
  using Scalar = Scalar_;
  using Vector2 = Matrix<Scalar, 2, 1>;
  using Matrix2 = Matrix<Scalar, 2, 2>;
 
 protected:
  Scalar m_angle;
 
 public:
  EIGEN_DEVICE_FUNC explicit inline Rotation2D(const Scalar& a) : m_angle(a) {}

  EIGEN_DEVICE_FUNC Rotation2D() {}

  template <typename Derived>
  EIGEN_DEVICE_FUNC explicit Rotation2D(const MatrixBase<Derived>& m) {
    fromRotationMatrix(m.derived());
  }

  EIGEN_DEVICE_FUNC inline Scalar angle() const { return m_angle; }

  EIGEN_DEVICE_FUNC inline Scalar& angle() { return m_angle; }

  EIGEN_DEVICE_FUNC inline Scalar smallestPositiveAngle() const {
    Scalar tmp = numext::fmod(m_angle, Scalar(2 * EIGEN_PI));
    return tmp < Scalar(0) ? tmp + Scalar(2 * EIGEN_PI) : tmp;
  }

  EIGEN_DEVICE_FUNC inline Scalar smallestAngle() const {
    Scalar tmp = numext::fmod(m_angle, Scalar(2 * EIGEN_PI));
    if (tmp > Scalar(EIGEN_PI))
      tmp -= Scalar(2 * EIGEN_PI);
    else if (tmp < -Scalar(EIGEN_PI))
      tmp += Scalar(2 * EIGEN_PI);
    return tmp;
  }

  EIGEN_DEVICE_FUNC inline Rotation2D inverse() const { return Rotation2D(-m_angle); }

  EIGEN_DEVICE_FUNC inline Rotation2D operator*(const Rotation2D& other) const {
    return Rotation2D(m_angle + other.m_angle);
  }

  EIGEN_DEVICE_FUNC inline Rotation2D& operator*=(const Rotation2D& other) {
    m_angle += other.m_angle;
    return *this;
  }

  EIGEN_DEVICE_FUNC Vector2 operator*(const Vector2& vec) const { return toRotationMatrix() * vec; }
 
  template <typename Derived>
  EIGEN_DEVICE_FUNC Rotation2D& fromRotationMatrix(const MatrixBase<Derived>& m);
  EIGEN_DEVICE_FUNC Matrix2 toRotationMatrix() const;

  template <typename Derived>
  EIGEN_DEVICE_FUNC Rotation2D& operator=(const MatrixBase<Derived>& m) {
    return fromRotationMatrix(m.derived());
  }

  EIGEN_DEVICE_FUNC inline Rotation2D slerp(const Scalar& t, const Rotation2D& other) const {
    Scalar dist = Rotation2D(other.m_angle - m_angle).smallestAngle();
    return Rotation2D(m_angle + dist * t);
  }

  template <typename NewScalarType>
  EIGEN_DEVICE_FUNC inline typename internal::cast_return_type<Rotation2D, Rotation2D<NewScalarType> >::type cast()
      const {
    return typename internal::cast_return_type<Rotation2D, Rotation2D<NewScalarType> >::type(*this);
  }

  template <typename OtherScalarType>
  EIGEN_DEVICE_FUNC inline explicit Rotation2D(const Rotation2D<OtherScalarType>& other) {
    m_angle = Scalar(other.angle());
  }
 
  EIGEN_DEVICE_FUNC static inline Rotation2D Identity() { return Rotation2D(0); }

  EIGEN_DEVICE_FUNC bool isApprox(const Rotation2D& other, const typename NumTraits<Scalar>::Real& prec =
                                                               NumTraits<Scalar>::dummy_precision()) const {
    return internal::isApprox(m_angle, other.m_angle, prec);
  }
};

using Rotation2Df = Rotation2D<float>;
using Rotation2Dd = Rotation2D<double>;

template <typename Scalar>
template <typename Derived>
EIGEN_DEVICE_FUNC Rotation2D<Scalar>& Rotation2D<Scalar>::fromRotationMatrix(const MatrixBase<Derived>& mat) {
  EIGEN_USING_STD(atan2)
  EIGEN_STATIC_ASSERT(Derived::RowsAtCompileTime == 2 && Derived::ColsAtCompileTime == 2,
                      YOU_MADE_A_PROGRAMMING_MISTAKE)
  m_angle = atan2(mat.coeff(1, 0), mat.coeff(0, 0));
  return *this;
}

template <typename Scalar>
typename Rotation2D<Scalar>::Matrix2 EIGEN_DEVICE_FUNC Rotation2D<Scalar>::toRotationMatrix(void) const {
  EIGEN_USING_STD(sin)
  EIGEN_USING_STD(cos)
  Scalar sinA = sin(m_angle);
  Scalar cosA = cos(m_angle);
  return (Matrix2() << cosA, -sinA, sinA, cosA).finished();
}
 
}  // end namespace Eigen
 
#endif  // EIGEN_ROTATION2D_H