#ifndef delaunay_H
#define delaunay_H

/* Delaunay triangulation. */
/* Last edited on 2011-12-24 01:02:33 by stolfilocal */

/*
** The divide-and-conquer algorithm for computing the Delaunay
** triangulation of a set of points (sites) on the plane. 
** For details, see 
**
**   "Primitives for the Manipulation of General Subdivisions 
**   and the Computation of Voronoi Diagrams"
**
**   L. Guibas, J. Stolfi, ACM Transactions on Graphics, April 1985
**
** Implemented by Jim Roth (DEC CADM Advanced Group) on May 1986.
** Adapted by J. Stolfi on April 1993.
** See the copyright notice at the end of this file.
*/

#include <quad.h>
#include <bool.h>
#include <sign.h>
#include <i3.h>
#include <hi2.h>
#include <r2.h>

#define delaunay_MAX_BITS_COORD (14)
  /* Number of bits used by a homogeneous site coordinate, excluding the sign. */

#define delaunay_MAX_COORD ((1 << delaunay_MAX_BITS_COORD)-1)
  /* Max absolute value of any homogeneous site coordinate. */

#define delaunay_COORD_FMT "6d"
  /* Format (minus the "%") to use when printing a site's homogeneous coord. */

typedef struct delaunay_site_t
  { hi2_point_t pt;  /* Homogeneous site coordinates (cooordinate 0 is the weight). */
    int index;       /* Site index. */
  } delaunay_site_t;

/* The Delaunay triangulation: */

quad_arc_t delaunay_build(delaunay_site_t sites[], int nsites);
  /* Builds the Delaunay trinagulation of {site[0..nsites-1]}.
    Returns an arc {e} on the perimeter of the triangulation,
    oriented so that {LEFT(e)} is the outer (unbounded) face. */

/* Quad-edge data pointers: */

#define ORG(e) ((delaunay_site_t *) quad_odata(e))
#define DST(e) ((delaunay_site_t *) quad_ddata(e))

#define SET_ORG(e,v) quad_set_odata(e, (void *)(v))
#define SET_DST(e,v) quad_set_ddata(e, (void *)(v))

/* Topology tools: */

quad_arc_t connect(quad_arc_t a, quad_arc_t b);

/* Geometric tools: */

r2_t delaunay_r2_from_hi2(hi2_point_t *ph);
  /* Converts homogeneous integer coordinates {h} to real Cartesian cooordinates. */

hi2_point_t delaunay_hi2_from_r2(r2_t *pc);
  /* Converts (with rounding) real Cartesian cooordinates {p} to homogeneous 
    integer coordinates whose absolute value does not exceed {delaunay_MAX_COORD}. */

sign_t delaunay_orient(delaunay_site_t *a, delaunay_site_t *b, delaunay_site_t *c);
  /* Orientation of the three sites {a,b,c}: positive means CCW,
    negative means CW, zero means they are collinear. */
   
bool_t delaunay_leftof (delaunay_site_t *s, quad_arc_t e);
  /* TRUE iff the site {s} lies to the left of the line {ORG(e)-->DEST(e)}. */
    
bool_t delaunay_rightof (delaunay_site_t *s, quad_arc_t e);
  /* TRUE iff the site {s} lies to the right of the line {ORG(e)-->DEST(e)}. */
    
bool_t delaunay_incircle (delaunay_site_t *a, delaunay_site_t *b, delaunay_site_t *c, delaunay_site_t *d);
  /* TRUE iff the site {d} lies inside the circle {a,b,c}. */

void delaunay_debug_site (char *msg, delaunay_site_t *a);
  /* Prints site {a} to {stderr} labeled with {msg}. */

void delaunay_debug_edge (char *msg, quad_arc_t e);
  /* Prints arc {e} to {stderr} labeled with {msg}. */

#endif

/*
** Copyright notice:
**
** Copyright 1996 Institute of Computing, Unicamp.
**
** Permission to use this software for any purpose is hereby granted,
** provided that any substantial copy or mechanically derived version
** of this file that is made available to other parties is accompanied
** by this copyright notice in full, and is distributed under these same
** terms. 
**
** DISCLAIMER: This software is provided "as is" with no explicit or
** implicit warranty of any kind.  Neither the authors nor their
** employers can be held responsible for any losses or damages
** that might be attributed to its use.
**
** End of copyright notice.
*/