#ifndef __FVM_TRIANGULATE_H__
#define __FVM_TRIANGULATE_H__

/*============================================================================
 * Triangulation of a polygon
 *============================================================================*/

/*
  This file is part of the "Finite Volume Mesh" library, intended to provide
  finite volume mesh and associated fields I/O and manipulation services.

  Copyright (C) 2005-2006  EDF

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

/*----------------------------------------------------------------------------
 *  Local headers
 *----------------------------------------------------------------------------*/

#include <fvm_defs.h>

/*----------------------------------------------------------------------------*/

#ifdef __cplusplus
extern "C" {
#if 0
} /* Fake brace to force back Emacs auto-indentation back to column 0 */
#endif
#endif /* __cplusplus */

/*=============================================================================
 * Macro definitions
 *============================================================================*/

/*============================================================================
 * Type definitions
 *============================================================================*/

/*
 * Pointer to structure maintaining the state of the current triangulation;
 * the structure itself is private.
 */

typedef struct _fvm_triangulate_state_t fvm_triangulate_state_t;

/*=============================================================================
 * Static global variables
 *============================================================================*/

/*=============================================================================
 * Public function prototypes
 *============================================================================*/

/*----------------------------------------------------------------------------
 * Create a structure necessary to the polygon triangulation algorithm.
 *
 * parameters:
 *   n_vertices_max    <-- maximum expected number of vertices per polygon.
 *
 * returns:
 *   pointer to polygon triangulation state structure.
 *----------------------------------------------------------------------------*/

fvm_triangulate_state_t *
fvm_triangulate_state_create(const int  n_vertices_max);

/*----------------------------------------------------------------------------
 * Destroy a structure necessary to the polygon triangulation algorithm.
 *
 * parameters:
 *   this_state  <-> pointer to structure that should be destroyed.
 *
 * returns:
 *   NULL pointer.
 *----------------------------------------------------------------------------*/

fvm_triangulate_state_t *
fvm_triangulate_state_destroy(fvm_triangulate_state_t  *this_state);

/*----------------------------------------------------------------------------
 * Triangulate a polygonal face.
 *
 * For a polygon with n vertices, we should obtain a triangluation with
 * (n-2) triangles and (2n-3) edges. If the polygon_vertices argument
 * is NULL, 1, 2, ...,n local numbering is implied.
 *
 * parameters:
 *   dim               <-- spatial dimension (2 or 3).
 *   n_vertices        <-- number of vertices defining the polygon.
 *   coords            <-- coordinates of the triangulation's vertices.
 *   parent_vertex_num <-- optional indirection to vertex coordinates (1 to n).
 *   polygon_vertices  <-- polygon connectivity; size: n_vertices or empty.
 *   triangle_vertices --> triangles connectivity;
 *                         size: (n_vertices - 2) * 3.
 *   state             <-> associated triangulation state structure.
 *
 * returns:
 *   number of resulting triangles.
 *----------------------------------------------------------------------------*/

int
fvm_triangulate_polygon(const int                       dim,
                        const int                       n_vertices,
                        const fvm_coord_t               coords[],
                        const fvm_lnum_t                parent_vertex_num[],
                        const fvm_lnum_t                polygon_vertices[],
                        fvm_lnum_t                      triangle_vertices[],
                        fvm_triangulate_state_t  *const state);

/*----------------------------------------------------------------------------*/

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* __FVM_TRIANGULATE_H__ */