Vamos Automotive Simulator git

//  Copyright (C) 2001-2019 Sam Varner
//
//  This file is part of Vamos Automotive Simulator.
//
//  Vamos is free software: 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 3 of the License, or
//  (at your option) any later version.
//
//  Vamos 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 General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with Vamos.  If not, see <http://www.gnu.org/licenses/>.

#ifndef _SPLINE_H_
#define _SPLINE_H_

#include "Interpolator.hpp"
#include "Three_Vector.hpp"
#include "Two_Vector.hpp"

#include <optional>
#include <vector>

namespace Vamos_Geometry
{
class Spline : public Interpolator
{
public:
    Spline();
    Spline(double first_slope, double last_slope);
    Spline(const std::vector<Two_Vector> &points);
    Spline(const std::vector<Two_Vector> &points, double first_slope, double last_slope);
    virtual ~Spline() = default;

    void set_periodic(double period_end);
    double slope(double distance) const;
    double second_derivative(double distance) const;

    virtual double interpolate(double dist) const override;
    virtual Two_Vector normal(double dist) const override;

private:
    // Calculate the coefficients for interpolation.
    void calculate() const;
    void check(double *a, double *b, double *r) const;

    // The array of calculated second derivatives.
    mutable std::vector<double> m_second_deriv;
    // The first derivative of the spline at the first point.
    std::optional<double> m_first_slope;
    // The first derivative of the spline at the last point.
    std::optional<double> m_last_slope;
    // The 1st and 2nd derivatives at the interpolated point calculated during the last
    // call to interpolate().
    mutable double m_slope = 0.0;
    mutable double m_second_derivative = 0.0;
    bool m_periodic = false;
};

class Parametric_Spline
{
public:
    Parametric_Spline();
    Parametric_Spline(double first_x_slope, double last_x_slope,
                      double first_y_slope, double last_y_slope);

    // Add a point to the curve.
    void load(double parameter, const Two_Vector &point);
    void load(double parameter, double x, double y) { load(parameter, Two_Vector(x, y)); }
    // Remove all points from the curve.
    void clear();
    void set_periodic(double period_end);
    // Return the point at PARAMETER.
    Two_Vector interpolate(double parameter) const;
    // Return the number of control points.
    size_t size() const;
    Two_Vector operator[](size_t i) const;
    double parameter(size_t i) const;

private:
    Spline m_x;
    Spline m_y;
};

class Vector_Spline
{
public:
    Vector_Spline();
    Vector_Spline(double first_x_slope, double last_x_slope, double first_y_slope,
                  double last_y_slope, double first_z_slope, double last_z_slope);

    // Add a point to the curve.
    void load(double parameter, const Vamos_Geometry::Three_Vector &point);
    void load(double parameter, double x, double y, double z)
    { load(parameter, Three_Vector(x, y, z)); }
    // Remove all points from the curve.
    void clear();
    void set_periodic(double period_end);
    // Return the point at PARAMETER.
    Vamos_Geometry::Three_Vector interpolate(double parameter) const;
    // Return the number of control points.
    size_t size() const;
    Vamos_Geometry::Three_Vector operator[](size_t i) const;
    double parameter(size_t i) const;

private:
    Spline m_x;
    Spline m_y;
    Spline m_z;
};
} // namespace Vamos_Geometry

#endif