OpenSpace/modules/autonavigation/pathcurve.h

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 * OpenSpace                                                                             *
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#ifndef __OPENSPACE_MODULE_AUTONAVIGATION___PATHCURVE___H__
#define __OPENSPACE_MODULE_AUTONAVIGATION___PATHCURVE___H__

#include <modules/autonavigation/waypoint.h>
#include <ghoul/glm.h>
#include <vector>

namespace openspace::autonavigation {

class PathCurve {
public:
    virtual ~PathCurve() = 0;

    const double length() const;
    glm::dvec3 positionAt(double relativeLength);

    // Compute curve parameter u that matches the input arc length s
    double curveParameter(double s);

    virtual glm::dvec3 interpolate(double u) = 0;

    std::vector<glm::dvec3> points();

protected:
    // Precompute information related to the pspline parameters, that are
    // needed for arc length reparameterization
    void initializeParameterData();

    double approximatedDerivative(double u, double h = 0.0001);
    double arcLength(double limit = 1.0);
    double arcLength(double lowerLimit, double upperLimit);

    std::vector<glm::dvec3> _points;
    unsigned int _nSegments;

    std::vector<double> _curveParameterSteps; // per segment
    std::vector<double> _arcLengthSums; // per segment
    double _totalLength;

    struct ParameterPair {
        double u; // curve parameter
        double s; // arc length parameter
    };

    std::vector<ParameterPair> _parameterSamples;
};

class LinearCurve : public PathCurve {
public:
    LinearCurve(const Waypoint& start, const Waypoint& end);
    glm::dvec3 interpolate(double u);
};

} // namespace openspace::autonavigation

#endif // __OPENSPACE_MODULE_AUTONAVIGATION___PATHCURVE___H__