CPose2D.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/math/CVectorFixed.h>
#include <mrpt/poses/CPose.h>
#include <mrpt/serialization/CSerializable.h>

namespace mrpt::poses
{
class CPose3D;
/** A class used to store a 2D pose, including the 2D coordinate point and a
 * heading (phi) angle.
 *  Use this class instead of lightweight mrpt::math::TPose2D when pose/point
 * composition is to be called
 *  multiple times with the same pose, since this class caches calls to
 * expensive trigronometric functions.
 *
 * For a complete description of Points/Poses, see mrpt::poses::CPoseOrPoint,
 * or refer to [this documentation page]
 *(http://www.mrpt.org/tutorials/programming/maths-and-geometry/2d_3d_geometry/)
 *
 *  <div align=center>
 *   <img src="CPose2D.gif">
 *  </div>
 *
 * \note Read also: "A tutorial on SE(3) transformation parameterizations and
 * on-manifold optimization", Jose-Luis Blanco.
 * http://ingmec.ual.es/~jlblanco/papers/jlblanco2010geometry3D_techrep.pdf
 * \sa CPoseOrPoint,CPoint2D
 * \ingroup poses_grp
 */
class CPose2D : public CPose<CPose2D, 3>,
                public mrpt::serialization::CSerializable
{
   public:
    DEFINE_SERIALIZABLE(CPose2D, mrpt::poses)
    DEFINE_SCHEMA_SERIALIZABLE()

   public:
    /** [x,y] */
    mrpt::math::CVectorFixedDouble<2> m_coords;

   protected:
    /** The orientation of the pose, in radians. */
    double m_phi{.0};
    /** Precomputed cos() & sin() of phi. */
    mutable double m_cosphi{1.0}, m_sinphi{.0};
    mutable bool m_cossin_uptodate{false};
    void update_cached_cos_sin() const;

   public:
    /** Default constructor (all coordinates to 0) */
    CPose2D();

    /** Constructor from an initial value of the pose.*/
    CPose2D(const double x, const double y, const double phi);

    /** Returns the identity transformation */
    static CPose2D Identity() { return CPose2D(); }

    /** Constructor from a CPoint2D object. */
    explicit CPose2D(const CPoint2D&);

    /** Aproximation!! Avoid its use, since information is lost. */
    explicit CPose2D(const CPose3D&);

    /** Constructor from lightweight object. */
    explicit CPose2D(const mrpt::math::TPose2D&);

    mrpt::math::TPose2D asTPose() const;

    /** Constructor from CPoint3D with information loss. */
    explicit CPose2D(const CPoint3D&);

    /** Fast constructor that leaves all the data uninitialized - call with
     * UNINITIALIZED_POSE as argument */
    inline CPose2D(TConstructorFlags_Poses) : m_cossin_uptodate(false) {}
    /** Get the phi angle of the 2D pose (in radians) */
    inline double phi() const { return m_phi; }
    //! \overload
    inline double& phi()
    {
        m_cossin_uptodate = false;
        return m_phi;
    }  //-V659

    /** Get a (cached) value of cos(phi), recomputing it only once when phi
     * changes. */
    inline double phi_cos() const
    {
        update_cached_cos_sin();
        return m_cosphi;
    }
    /** Get a (cached) value of sin(phi), recomputing it only once when phi
     * changes. */
    inline double phi_sin() const
    {
        update_cached_cos_sin();
        return m_sinphi;
    }

    /** Set the phi angle of the 2D pose (in radians) */
    inline void phi(double angle)
    {
        m_phi = angle;
        m_cossin_uptodate = false;
    }

    /** Increment the PHI angle (without checking the 2 PI range, call
     * normalizePhi is needed) */
    inline void phi_incr(const double Aphi)
    {
        m_phi += Aphi;
        m_cossin_uptodate = false;
    }

    /** Returns a 1x3 vector with [x y phi] */
    void asVector(vector_t& v) const;

    /** Returns the corresponding 4x4 homogeneous transformation matrix for the
     * point(translation) or pose (translation+orientation).
     * \sa getInverseHomogeneousMatrix
     */
    void getHomogeneousMatrix(mrpt::math::CMatrixDouble44& out_HM) const;

    /** Returns the SE(2) 2x2 rotation matrix */
    void getRotationMatrix(mrpt::math::CMatrixDouble22& R) const;
    /** Returns the equivalent SE(3) 3x3 rotation matrix, with (2,2)=1. */
    void getRotationMatrix(mrpt::math::CMatrixDouble33& R) const;

    template <class MATRIX22>
    inline MATRIX22 getRotationMatrix() const
    {
        MATRIX22 R;
        getRotationMatrix(R);
        return R;
    }

    /** The operator \f$ a = this \oplus D \f$ is the pose compounding operator.
     */
    CPose2D operator+(const CPose2D& D) const;

    /** Makes \f$ this = A \oplus B \f$
     *  \note A or B can be "this" without problems.  */
    void composeFrom(const CPose2D& A, const CPose2D& B);

    /** The operator \f$ a = this \oplus D \f$ is the pose compounding operator.
     */
    CPose3D operator+(const CPose3D& D) const;

    /** The operator \f$ u' = this \oplus u \f$ is the pose/point compounding
     * operator.  */
    CPoint2D operator+(const CPoint2D& u) const;

    /** An alternative, slightly more efficient way of doing \f$ G = P \oplus L
     * \f$ with G and L being 2D points and P this 2D pose.  */
    void composePoint(double lx, double ly, double& gx, double& gy) const;

    /** overload \f$ G = P \oplus L \f$ with G and L being 2D points and P this
     * 2D pose */
    void composePoint(
        const mrpt::math::TPoint2D& l, mrpt::math::TPoint2D& g) const;

    /// \overload
    mrpt::math::TPoint3D composePoint(const mrpt::math::TPoint3D& l) const;

    /** overload \f$ G = P \oplus L \f$ with G and L being 3D points and P this
     * 2D pose (the "z" coordinate remains unmodified) */
    void composePoint(
        const mrpt::math::TPoint3D& l, mrpt::math::TPoint3D& g) const;
    /** overload (the "z" coordinate remains unmodified) */
    void composePoint(
        double lx, double ly, double lz, double& gx, double& gy,
        double& gz) const;

    /**  Computes the 2D point L such as \f$ L = G \ominus this \f$. \sa
     * composePoint, composeFrom */
    void inverseComposePoint(
        const double gx, const double gy, double& lx, double& ly) const;
    /** \overload */
    void inverseComposePoint(
        const mrpt::math::TPoint2D& g, mrpt::math::TPoint2D& l) const;
    /** \overload */
    mrpt::math::TPoint2D inverseComposePoint(
        const mrpt::math::TPoint2D& g) const;

    /** The operator \f$ u' = this \oplus u \f$ is the pose/point compounding
     * operator. */
    CPoint3D operator+(const CPoint3D& u) const;

    /**  Makes \f$ this = A \ominus B \f$ this method is slightly more efficient
     * than "this= A - B;" since it avoids the temporary object.
     *  \note A or B can be "this" without problems.
     * \sa composeFrom, composePoint
     */
    void inverseComposeFrom(const CPose2D& A, const CPose2D& B);

    /** Convert this pose into its inverse, saving the result in itself. \sa
     * operator- */
    void inverse();

    /** Compute \f$ RET = this \ominus b \f$  */
    inline CPose2D operator-(const CPose2D& b) const
    {
        CPose2D ret(UNINITIALIZED_POSE);
        ret.inverseComposeFrom(*this, b);
        return ret;
    }

    /** The operator \f$ a \ominus b \f$ is the pose inverse compounding
     * operator. */
    CPose3D operator-(const CPose3D& b) const;

    /** Scalar sum of components: This is diferent from poses
     *    composition, which is implemented as "+" operators in "CPose" derived
     * classes.
     */
    void AddComponents(const CPose2D& p);

    /** Scalar multiplication.
     */
    void operator*=(const double s);

    /** Make \f$ this = this \oplus b \f$  */
    CPose2D& operator+=(const CPose2D& b);

    /** Forces "phi" to be in the range [-pi,pi];
     */
    void normalizePhi();

    /** Return the opposite of the current pose instance by taking the negative
     * of all its components \a individually
     */
    CPose2D getOppositeScalar() const;

    /** Returns a human-readable textual representation of the object (eg: "[x y
     * yaw]", yaw in degrees)
     * \sa fromString
     */
    void asString(std::string& s) const;
    inline std::string asString() const
    {
        std::string s;
        asString(s);
        return s;
    }

    /** Set the current object value from a string generated by 'asString' (eg:
     * "[0.02 1.04 -0.8]" )
     * \sa asString
     * \exception std::exception On invalid format
     */
    void fromString(const std::string& s);
    /** Same as fromString, but without requiring the square brackets in the
     * string */
    void fromStringRaw(const std::string& s);

    static CPose2D FromString(const std::string& s)
    {
        CPose2D o;
        o.fromString(s);
        return o;
    }

    inline double operator[](unsigned int i) const
    {
        switch (i)
        {
            case 0:
                return m_coords[0];
            case 1:
                return m_coords[1];
            case 2:
                return m_phi;
            default:
                throw std::runtime_error(
                    "CPose2D::operator[]: Index of bounds.");
        }
    }
    inline double& operator[](unsigned int i)
    {
        switch (i)
        {
            case 0:
                return m_coords[0];
            case 1:
                return m_coords[1];
            case 2:
                return m_phi;
            default:
                throw std::runtime_error(
                    "CPose2D::operator[]: Index of bounds.");
        }
    }

    /** makes: this = p (+) this */
    inline void changeCoordinatesReference(const CPose2D& p)
    {
        composeFrom(p, CPose2D(*this));
    }

    /** Returns the 2D distance from this pose/point to a 2D pose using the
     * Frobenius distance. */
    double distance2DFrobeniusTo(const CPose2D& p) const;

    /** Used to emulate CPosePDF types, for example, in
     * mrpt::graphs::CNetworkOfPoses */
    using type_value = CPose2D;
    enum
    {
        is_3D_val = 0
    };
    static constexpr bool is_3D() { return is_3D_val != 0; }
    enum
    {
        rotation_dimensions = 2
    };
    enum
    {
        is_PDF_val = 0
    };
    static constexpr bool is_PDF() { return is_PDF_val != 0; }
    inline const type_value& getPoseMean() const { return *this; }
    inline type_value& getPoseMean() { return *this; }
    void setToNaN() override;

    /** @name STL-like methods and typedefs
       @{   */
    /** The type of the elements */
    using value_type = double;
    using reference = double&;
    using const_reference = double;
    using size_type = std::size_t;
    using difference_type = std::ptrdiff_t;

    // size is constant
    enum
    {
        static_size = 3
    };
    static constexpr size_type size() { return static_size; }
    static constexpr bool empty() { return false; }
    static constexpr size_type max_size() { return static_size; }
    static inline void resize(const size_t n)
    {
        if (n != static_size)
            throw std::logic_error(format(
                "Try to change the size of CPose2D to %u.",
                static_cast<unsigned>(n)));
    }

    /** @} */

};  // End of class def.

std::ostream& operator<<(std::ostream& o, const CPose2D& p);

/** Unary - operator: return the inverse pose "-p" (Note that is NOT the same
 * than a pose with negative x y phi) \sa CPose2D::inverse() */
CPose2D operator-(const CPose2D& p);

/** Compose a 2D point from a new coordinate base given by a 2D pose. */
mrpt::math::TPoint2D operator+(
    const CPose2D& pose, const mrpt::math::TPoint2D& pnt);

bool operator==(const CPose2D& p1, const CPose2D& p2);
bool operator!=(const CPose2D& p1, const CPose2D& p2);

}  // namespace mrpt::poses