line.h

// Description: Line

#ifndef PASTELGEOMETRY_LINE_H
#define PASTELGEOMETRY_LINE_H

#include "pastel/sys/vector.h"
#include "pastel/sys/tuple.h"

#include <boost/operators.hpp>

namespace Pastel
{

    //! A straight line.
    /*!
   For performance reasons it must be required that
   the line direction always be of unit length.
   This is not enforced by the system but is required
   by the algorithms.
   */
    template <typename Real, integer N = Dynamic>
    class Line
        : boost::multipliable<Line<Real, N>, Real
        , boost::dividable<Line<Real, N>, Real
        , boost::addable<Line<Real, N>, Vector<Real, N>
        , boost::subtractable<Line<Real, N>, Vector<Real, N>
        > > > >
    {
    public:
        using Real_ = Real;
        static constexpr integer N_ = N;

        // Using default copy constructor.
        // Using default assignment.
        // Using default destructor.

        //! Construct a line parallel to x-axis.
        Line();

        //! Construct a line parallel to x-axis.
        explicit Line(integer dimension);

        //! Construct a line given position and direction.
        Line(const Vector<Real, N>& position,
            const Vector<Real, N>& unitDirection);

        //! Construct a line given position and direction.
        Line(integer dimension, 
            const Vector<Real, N>& position,
            const Vector<Real, N>& unitDirection);

        // Used for concept checking.
        ~Line();

        //! Swaps two lines.
        void swap(Line<Real, N>& that);

        //! Sets the position and direction of the line.
        void set(const Vector<Real, N>& position,
            const Vector<Real, N>& unitDirection);

        //! Returns the dimension of the line.
        integer n() const;

        //! Sets the position of the line.
        void setPosition(const Vector<Real, N>& position);

        //! Returns the position of the line.
        const Vector<Real, N>& position() const;

        //! Sets the direction of the line.
        void setDirection(const Vector<Real, N>& unitDirection);

        //! Returns the direction of the line.
        const Vector<Real, N>& direction() const;

        //! Returns the direction of the line inverted.
        /*!
       Inversion is done component-wise. This caching
       is meant to enable faster algorithms since
       division is costly to compute.
       */
        const Vector<Real, N>& inverseDirection() const;

        //! Returns the point (position + t * direction).
        Vector<Real, N> at(const Real& t) const;

        //! Translates the line by the given vector.
        Line<Real, N>& operator+=(const Vector<Real, N>& that);

        //! Translates the line backwards by the given vector.
        Line<Real, N>& operator-=(const Vector<Real, N>& that);

        //! Scales up the line without affecting position.
        Line<Real, N>& operator*=(const Real& that);

        //! Scales down the line without affecting position.
        Line<Real, N>& operator/=(const Real& that);

    private:
        Vector<Real, N> position_;
        Vector<Real, N> direction_;
        Vector<Real, N> inverseDirection_;
    };

    using Line1 = Line<real, 1>;
    using Line2 = Line<real, 2>;
    using Line3 = Line<real, 3>;
    using Line4 = Line<real, 4>;
    using LineD = Line<real, Dynamic>;

}

#include "pastel/geometry/shape/line.hpp"

#endif