// This file is part of libigl, a simple c++ geometry processing library.
// 
// Copyright (C) 2016 Yotam Gingold <yotam@yotamgingold.com>
// 
// 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_SEAM_EDGES_H
#define IGL_SEAM_EDGES_H
#include "igl_inline.h"
#include <Eigen/Core>
namespace igl
{
    /*
    Returns all UV-space boundaries of a mesh.
    Inputs:
        V: The positions of the input mesh.
        TC: The 2D texture coordinates of the input mesh (2 columns).
        F: A manifold-with-boundary triangle mesh, as vertex indices into `V` for the three vertices of each triangle.
        FTC: Indices into `TC` for the three vertices of each triangle.
    Outputs:
        seams: Edges where the forwards and backwards directions have different texture
               coordinates, as a #seams-by-4 matrix of indices.
               Each row is organized as [ forward_face_index, forward_face_vertex_index,
               backwards_face_index, backwards_face_vertex_index ]
               such that one side of the seam is the edge:
                    F[ seams( i, 0 ), seams( i, 1 ) ], F[ seams( i, 0 ), (seams( i, 1 ) + 1) % 3 ]
               and the other side is the edge:
                    F[ seams( i, 2 ), seams( i, 3 ) ], F[ seams( i, 2 ), (seams( i, 3 ) + 1) % 3 ]
        boundaries: Edges with only one incident triangle, as a #boundaries-by-2 matrix of
                    indices. Each row is organized as [ face_index, face_vertex_index ]
                    such that the edge is:
                        F[ boundaries( i, 0 ), boundaries( i, 1 ) ], F[ boundaries( i, 0 ), (boundaries( i, 1 ) + 1) % 3 ]
        foldovers: Edges where the two incident triangles fold over each other in UV-space,
                   as a #foldovers-by-4 matrix of indices.
                   Each row is organized as [ forward_face_index, forward_face_vertex_index,
                   backwards_face_index, backwards_face_vertex_index ]
                   such that one side of the foldover is the edge:
                        F[ foldovers( i, 0 ), foldovers( i, 1 ) ], F[ foldovers( i, 0 ), (foldovers( i, 1 ) + 1) % 3 ]
                   and the other side is the edge:
                        F[ foldovers( i, 2 ), foldovers( i, 3 ) ], F[ foldovers( i, 2 ), (foldovers( i, 3 ) + 1) % 3 ]
    */
    template <typename DerivedV, typename DerivedF, typename DerivedT>
    IGL_INLINE void seam_edges(
        const Eigen::PlainObjectBase<DerivedV>& V,
        const Eigen::PlainObjectBase<DerivedT>& TC,
        const Eigen::PlainObjectBase<DerivedF>& F,
        const Eigen::PlainObjectBase<DerivedF>& FTC,
        Eigen::PlainObjectBase<DerivedF>& seams,
        Eigen::PlainObjectBase<DerivedF>& boundaries,
        Eigen::PlainObjectBase<DerivedF>& foldovers
        );
}
#ifndef IGL_STATIC_LIBRARY
#   include "seam_edges.cpp"
#endif
#endif // IGL_SEAM_EDGES_H