// This file is part of libigl, a simple c++ geometry processing library.
//
// Copyright (C) 2016 Francisca Gil Ureta <gilureta@cs.nyu.edu>
//
// This Source Code Form is subject to the terms of the Mozilla Public License
// v. 2.0. If a copy of the MPL was not distributed with this file, You can
// obtain one at http://mozilla.org/MPL/2.0/.

#ifndef IGL_SEGMENT_SEGMENT_INTERSECT_H
#define IGL_SEGMENT_SEGMENT_INTERSECT_H


#include "igl_inline.h"
#include <Eigen/Core>
namespace igl
{

    // Determine whether two line segments A,B intersect
    // A: p + t*r :  t \in [0,1]
    // B: q + u*s :  u \in [0,1]
    // Inputs:
    //   p  3-vector origin of segment A
    //   r  3-vector direction of segment A
    //   q  3-vector origin of segment B
    //   s  3-vector direction of segment B
    //  eps precision
    // Outputs:
    //   t  scalar point of intersection along segment A, t \in [0,1]
    //   u  scalar point of intersection along segment B, u \in [0,1]
    // Returns true if intersection
    template<typename DerivedSource, typename DerivedDir>
    IGL_INLINE bool segment_segment_intersect(
            const Eigen::PlainObjectBase <DerivedSource> &p,
            const Eigen::PlainObjectBase <DerivedDir> &r,
            const Eigen::PlainObjectBase <DerivedSource> &q,
            const Eigen::PlainObjectBase <DerivedDir> &s,
            double &t,
            double &u,
            double eps = 1e-6
    );

}
#ifndef IGL_STATIC_LIBRARY
#   include "segment_segment_intersect.cpp"
#endif
#endif //IGL_SEGMENT_SEGMENT_INTERSECT_H