overlaps_alignedplane_sphere.h

// Description: Overlap tests between an aligned plane and a sphere

#ifndef PASTELGEOMETRY_OVERLAPS_ALIGNEDPLANE_SPHERE_H
#define PASTELGEOMETRY_OVERLAPS_ALIGNEDPLANE_SPHERE_H

#include "pastel/geometry/shape/alignedplane.h"
#include "pastel/geometry/shape/sphere.h"
#include "pastel/sys/mytypes.h"

namespace Pastel
{

    //! Tests if an aligned plane and a sphere overlap.
    /*!
   Preconditions:
   plane.n() == sphere.dimension

   Time complexity:
   O(1)
   */
    template <typename Real, int N>
    bool overlaps(
        const AlignedPlane<Real, N>& plane,
        const Sphere<Real, N>& sphere)
    {
        PENSURE_OP(plane.n(), ==, sphere.n());

        Real distance = 
            abs(sphere.position()[plane.axis()] -
            plane.position());

        if (distance >= sphere.radius())
        {
            if (distance > sphere.radius() ||
                sphere.topology() == Topology::Open)
            {
                return false;
            }
        }

        return false;
    }

    //! Tests if an aligned plane and a sphere overlap.
    /*!
   sphereOnPositiveSide: 
   Filled with information if the center of the sphere 
   is on the positive side of the plane.

   Returns:
   overlaps(plane, sphere)
   */
    template <typename Real, int N>
    bool overlaps(
        const AlignedPlane<Real, N>& plane,
        const Sphere<Real, N>& sphere,
        bool& sphereOnPositiveSide)
    {
        PENSURE_OP(plane.n(), ==, sphere.n());

        Real delta =
            sphere.position()[plane.axis()] -
            plane.position();

        sphereOnPositiveSide = delta > 0;

        return Pastel::overlaps(plane, sphere);
    }

}

#endif