flat.h

// Description: Flat class

#ifndef PASTELGEOMETRY_FLAT_H
#define PASTELGEOMETRY_FLAT_H

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

namespace Pastel
{

    //! An M-flat.

    /*!
   An M-flat is an object that is the span
   of M linearly independent vectors added
   to a point. It is described by M
   tangent vectors plus a point.
   For specific examples, 1-flat is a line,
   (N - 1)-flat is a (hyper)plane.
   Clearly it must be that M <= N.
   */
    template <typename Real, int N, int M>
    class Flat
    {
    public:
        using Real_ = Real;
        static constexpr int N_ = N;
        static constexpr int M_ = M;

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

        // Used for concept checking.
        ~Flat()
        {
            PASTEL_STATIC_ASSERT(N == Dynamic || N > 0);
            PASTEL_STATIC_ASSERT(M <= N);
        }

        //! Sets the position of the flat.
        void setPosition(const Vector<Real, N>& position)
        {
            position_ = position;
        }

        //! Returns the position of the flat.
        const Vector<Real, N>& position() const
        {
            return position_;
        }

        //! Returns a specific tangent vector of the flat.
        Vector<Real, N>& operator[](integer index)
        {
            PENSURE2(index >= 0 && index < M, index, M);

            return tangent_[index];
        }

        //! Returns a specific tangent vector of the flat.
        const Vector<Real, N>& operator[](integer index) const
        {
            PENSURE2(index >= 0 && index < M, index, M);

            return tangent_[index];
        }

    private:
        Vector<Real, N> position_;
        Tuple<Vector<Real, N>, M> tangent_;
    };

}

#endif