overlaps_flat_plane.h

// Description: Overlap tests between a 2-flat and a plane

#ifndef PASTELGEOMETRY_OVERLAPS_FLAT_PLANE_H
#define PASTELGEOMETRY_OVERLAPS_FLAT_PLANE_H

#include "pastel/geometry/shape/flat.h"
#include "pastel/geometry/shape/plane.h"
#include "pastel/geometry/shape/line.h"

#include "pastel/sys/vector.h"
#include "pastel/sys/math/constants.h"

namespace Pastel
{

    //! Tests if a 2-flat and a hyperplane overlap.
    template <typename Real, int N>
    bool overlaps(
        const Flat<Real, N, 2>& aPlane,
        const Plane<Real, N>& bPlane)
    {
        Real divider(
            dot(aPlane[0], bPlane.normal()));
        Vector<Real, N> delta(
            bPlane.position() - aPlane.position());

        // EPSILON
        if (divider == 0)
        {
            // EPSILON
            if (dot(delta, delta) == 0)
            {
                // Planes overlap
                return true;
            }

            return false;
        }

        return true;
    }

}

#endif