distance_segment_sphere.h

// Description: Distance between a line segment and a sphere

#ifndef PASTELGEOMETRY_DISTANCE_SEGMENT_SPHERE_H
#define PASTELGEOMETRY_DISTANCE_SEGMENT_SPHERE_H

#include "pastel/geometry/shape/segment.h"
#include "pastel/geometry/shape/sphere.h"
#include "pastel/geometry/distance/distance_segment_point.h"
#include "pastel/math/norm/euclidean_norm.h"

#include <cmath>

namespace Pastel
{

    //! Euclidean distance between a line segment and a sphere.
    /*!
   Preconditions:
   segment.n() == sphere.n()

   Time complexity: O(segment.n())
   */
    template <typename Real, int N>
    auto distance2(
        const Segment<Real, N>& segment,
        const Sphere<Real, N>& sphere)
    {
        PENSURE_OP(segment.n(), ==, sphere.n());

        auto norm = Euclidean_Norm<Real>();
        auto centerDistance = Pastel::distance2(segment, sphere.position());
        if (centerDistance <= sphere.radius()) return norm();

        return norm((Real)centerDistance - sphere.radius());
    }

}

#endif