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cdt.c
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/* GTS - Library for the manipulation of triangulated surfaces
* Copyright (C) 1999 Stéphane Popinet
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <math.h>
#include "gts.h"
#ifdef USE_SURFACE_BTREE
static gint find_closest (GtsTriangle * t, gpointer value, gpointer * data)
{
guint * ns = data[2];
guint * n = data[3];
if (*n >= *ns)
return TRUE;
else {
gdouble * dmin = data[0];
gpointer * closest = data[1];
GtsPoint * p = data[4];
if (gts_triangle_orientation (t) > 0.) {
GtsPoint * p1 = GTS_POINT (GTS_SEGMENT (t->e1)->v1);
gdouble d = (p->x - p1->x)*(p->x - p1->x) + (p->y - p1->y)*(p->y - p1->y);
if (d < *dmin) {
*dmin = d;
*closest = t;
}
(*n)++;
}
}
return FALSE;
}
/* select the face closest to @p among n^1/3 randomly picked faces
* of @surface */
static GtsFace * closest_face (GtsSurface * s, GtsPoint * p)
{
guint n = 0, nt, ns;
gdouble dmin = G_MAXDOUBLE;
GtsFace * closest = NULL;
gpointer data[5];
nt = gts_surface_face_number (s);
if (!nt)
return NULL;
ns = exp (log ((gdouble) nt)/3.);
data[0] = &dmin;
data[1] = &closest;
data[2] = &ns;
data[3] = &n;
data[4] = p;
g_tree_traverse (s->faces, (GTraverseFunc) find_closest, G_IN_ORDER, data);
return closest;
}
#else /* not USE_SURFACE_BTREE */
typedef struct _SFindClosest SFindClosest;
struct _SFindClosest {
gdouble dmin;
GtsFace *closest;
GtsPoint * p;
gint stop;
};
# if GLIB_CHECK_VERSION(2,4,0)
/* finally, with g_hash_table_find we are able to stop iteration over the hash
table in the middle */
static gboolean find_closest (gpointer key, gpointer value, gpointer user_data)
{
SFindClosest * data = (SFindClosest *) user_data;
GtsFace * f = GTS_FACE (value);
if (gts_triangle_orientation (GTS_TRIANGLE (f)) > 0.) {
GtsPoint * p1 = GTS_POINT (GTS_SEGMENT (GTS_TRIANGLE (f)->e1)->v1);
gdouble d = ((data->p->x - p1->x)*(data->p->x - p1->x) +
(data->p->y - p1->y)*(data->p->y - p1->y));
if (d < data->dmin) {
data->dmin = d;
data->closest = f;
}
}
data->stop--;
return !(data->stop > 0);
}
static GtsFace * closest_face (GtsSurface * s, GtsPoint * p)
{
SFindClosest fc;
fc.dmin = G_MAXDOUBLE;
fc.closest = NULL;
fc.p = p;
fc.stop = (gint) exp (log ((gdouble) g_hash_table_size (s->faces))/3.);
g_hash_table_find (s->faces, find_closest, &fc);
return fc.closest;
}
# else /* VERSION < 2.4.0 */
static void
find_closest (gpointer key, gpointer value, gpointer user_data)
{
SFindClosest * data = (SFindClosest *) user_data;
GtsFace * f = GTS_FACE (value);
if (gts_triangle_orientation (GTS_TRIANGLE (f)) > 0.) {
GtsPoint * p1 = GTS_POINT (GTS_SEGMENT (GTS_TRIANGLE (f)->e1)->v1);
gdouble d = ((data->p->x - p1->x)*(data->p->x - p1->x) +
(data->p->y - p1->y)*(data->p->y - p1->y));
if (d < data->dmin) {
data->dmin = d;
data->closest = f;
}
}
data->stop--;
}
/* select the face closest to @p among n^1/3 randomly picked faces
* of @surface */
static GtsFace * closest_face (GtsSurface * s, GtsPoint * p)
{
SFindClosest fc;
if (!g_hash_table_size (s->faces))
return NULL;
fc.dmin = G_MAXDOUBLE;
fc.closest = NULL;
fc.p = p;
fc.stop = (gint) exp (log ((gdouble) g_hash_table_size (s->faces))/3.);
g_hash_table_foreach (s->faces, find_closest, &fc);
return fc.closest;
}
# endif /* VERSION < 2.4.0 */
#endif /* not USE_SURFACE_BTREE */
/* returns the face belonging to @surface and neighbor of @f via @e */
static GtsFace * neighbor (GtsFace * f,
GtsEdge * e,
GtsSurface * surface)
{
GSList * i = e->triangles;
GtsTriangle * t = GTS_TRIANGLE (f);
while (i) {
GtsTriangle * t1 = i->data;
if (t1 != t &&
GTS_IS_FACE (t1) &&
gts_face_has_parent_surface (GTS_FACE (t1), surface))
return GTS_FACE (t1);
i = i->next;
}
return NULL;
}
/* given a triangle @t and a segment s (@o -> @p).
@o must be in @t. Returns the
edge of @t which is intersected by s or %NULL if @p is also
contained in @t (on_summit is set to %FALSE) or if s intersects @t
exactly on one of its summit (on_summit is set to %TRUE). */
static GtsEdge * triangle_next_edge (GtsTriangle * t,
GtsPoint * o, GtsPoint * p,
gboolean * on_summit)
{
GtsVertex * v1, * v2, * v3;
GtsEdge * e1, * e2, * e3;
gdouble orient = 0.0;
gts_triangle_vertices_edges (t, NULL,
&v1, &v2, &v3,
&e1, &e2, &e3);
*on_summit = FALSE;
orient = gts_point_orientation (o, GTS_POINT (v1), p);
if (orient > 0.0) {
orient = gts_point_orientation (o, GTS_POINT (v2), p);
if (orient > 0.0) {
if (gts_point_orientation (GTS_POINT (v2), GTS_POINT (v3), p) >= 0.0)
return NULL;
return e2;
}
if (orient < 0.0) {
if (gts_point_orientation (GTS_POINT (v1), GTS_POINT (v2), p) >= 0.0)
return NULL;
return e1;
}
if (gts_point_orientation (GTS_POINT (v1), GTS_POINT (v2), p) < 0.0)
*on_summit = TRUE;
return NULL;
}
if (orient < 0.0) {
orient = gts_point_orientation (o, GTS_POINT (v3), p);
if (orient > 0.0) {
if (gts_point_orientation (GTS_POINT (v3), GTS_POINT (v1), p) >= 0.0)
return NULL;
return e3;
}
if (orient < 0.0) {
if (gts_point_orientation (GTS_POINT (v2), GTS_POINT (v3), p) >= 0.0)
return NULL;
return e2;
}
if (gts_point_orientation (GTS_POINT (v3), GTS_POINT (v1), p) < 0.0)
*on_summit = TRUE;
return NULL;
}
if (gts_point_orientation (GTS_POINT (v2), GTS_POINT (v3), p) < 0.0)
return e2;
if (gts_point_orientation (GTS_POINT (v1), GTS_POINT (v2), p) < 0.0)
*on_summit = TRUE;
return NULL;
}
static void triangle_barycenter (GtsTriangle * t, GtsPoint * b)
{
GtsPoint * p = GTS_POINT (gts_triangle_vertex (t));
b->x = (p->x +
GTS_POINT (GTS_SEGMENT(t->e1)->v1)->x +
GTS_POINT (GTS_SEGMENT(t->e1)->v2)->x)/3.;
b->y = (p->y +
GTS_POINT (GTS_SEGMENT(t->e1)->v1)->y +
GTS_POINT (GTS_SEGMENT(t->e1)->v2)->y)/3.;
}
static GtsFace * point_locate (GtsPoint * o,
GtsPoint * p,
GtsFace * f,
GtsSurface * surface)
{
GtsEdge * prev;
gboolean on_summit;
GtsVertex * v1, * v2, * v3;
GtsEdge * e2, * e3;
prev = triangle_next_edge (GTS_TRIANGLE (f), o, p, &on_summit);
if (!prev) {
GtsFace * f1;
if (!on_summit)
return f; /* p is inside f */
/* s intersects f exactly on a summit: restarts from a neighbor of f */
if ((f1 = neighbor (f, GTS_TRIANGLE (f)->e1, surface)) ||
(f1 = neighbor (f, GTS_TRIANGLE (f)->e2, surface)) ||
(f1 = neighbor (f, GTS_TRIANGLE (f)->e3, surface))) {
triangle_barycenter (GTS_TRIANGLE (f1), o);
return point_locate (o, p, f1, surface);
}
return NULL;
}
f = neighbor (f, prev, surface);
if (f)
gts_triangle_vertices_edges (GTS_TRIANGLE (f), prev,
&v1, &v2, &v3, &prev, &e2, &e3);
while (f) {
gdouble orient = gts_point_orientation (o, GTS_POINT (v3), p);
if (orient < 0.0) {
if (gts_point_orientation (GTS_POINT (v2), GTS_POINT (v3), p) >= 0.0)
return f; /* p is inside f */
f = neighbor (f, e2, surface);
prev = e2;
v1 = v3;
}
else if (orient > 0.0) {
if (gts_point_orientation (GTS_POINT (v3), GTS_POINT (v1), p) >= 0.0)
return f; /* p is inside f */
f = neighbor (f, e3, surface);
prev = e3;
v2 = v3;
}
else {
GtsFace * f1;
if (gts_point_orientation (GTS_POINT (v2), GTS_POINT (v3), p) >= 0.0)
return f; /* p is inside f */
/* s intersects f exactly on v3: restarts from a neighbor of f */
if ((f1 = neighbor (f, e2, surface)) ||
(f1 = neighbor (f, e3, surface))) {
triangle_barycenter (GTS_TRIANGLE (f1), o);
return point_locate (o, p, f1, surface);
}
return NULL;
}
/* update e2, e3, v3 for the new triangle */
if (f) {
if (prev == GTS_TRIANGLE (f)->e1) {
e2 = GTS_TRIANGLE (f)->e2; e3 = GTS_TRIANGLE (f)->e3;
}
else if (prev == GTS_TRIANGLE (f)->e2) {
e2 = GTS_TRIANGLE (f)->e3; e3 = GTS_TRIANGLE (f)->e1;
}
else {
e2 = GTS_TRIANGLE (f)->e1; e3 = GTS_TRIANGLE (f)->e2;
}
if (GTS_SEGMENT (e2)->v1 == v1 || GTS_SEGMENT (e2)->v1 == v2)
v3 = GTS_SEGMENT (e2)->v2;
else
v3 = GTS_SEGMENT (e2)->v1;
}
}
return NULL;
}
/**
* gts_point_locate:
* @p: a #GtsPoint.
* @surface: a #GtsSurface.
* @guess: %NULL or a face of @surface close to @p.
*
* Locates the face of the planar projection of @surface containing
* @p. The planar projection of @surface must define a connected set
* of triangles without holes and bounded by a convex boundary. The
* algorithm is randomized and performs in O(n^1/3) expected time
* where n is the number of triangles of @surface.
*
* If a good @guess is given the point location can be significantly faster.
*
* Returns: a #GtsFace of @surface containing @p or %NULL if @p is not
* contained within the boundary of @surface.
*/
GtsFace * gts_point_locate (GtsPoint * p,
GtsSurface * surface,
GtsFace * guess)
{
GtsFace * fr;
GtsPoint * o;
g_return_val_if_fail (p != NULL, NULL);
g_return_val_if_fail (surface != NULL, NULL);
g_return_val_if_fail (guess == NULL ||
gts_face_has_parent_surface (guess, surface), NULL);
if (guess == NULL)
guess = closest_face (surface, p);
else
g_return_val_if_fail (gts_triangle_orientation (GTS_TRIANGLE (guess)) > 0., NULL);
if (guess == NULL)
return NULL;
o = GTS_POINT (gts_object_new (GTS_OBJECT_CLASS (gts_point_class ())));
triangle_barycenter (GTS_TRIANGLE (guess), o);
fr = point_locate (o, p, guess, surface);
gts_object_destroy (GTS_OBJECT (o));
return fr;
}
/**
* gts_constraint_class:
*
* Returns: the #GtsConstraintClass.
*/
GtsConstraintClass * gts_constraint_class (void)
{
static GtsConstraintClass * klass = NULL;
if (klass == NULL) {
GtsObjectClassInfo constraint_info = {
"GtsConstraint",
sizeof (GtsConstraint),
sizeof (GtsConstraintClass),
(GtsObjectClassInitFunc) NULL,
(GtsObjectInitFunc) NULL,
(GtsArgSetFunc) NULL,
(GtsArgGetFunc) NULL
};
klass = gts_object_class_new (GTS_OBJECT_CLASS (gts_edge_class ()),
&constraint_info);
}
return klass;
}
static void split_list (GtsListFace * f, GtsListFace * f1, GtsListFace * f2,
GtsPoint * p1, GtsPoint * p2,
GSList ** last1, GSList ** last2)
{
GSList * i = f->points, * l1 = *last1, * l2 = *last2;
while (i) {
GtsPoint * p = i->data;
if (gts_point_orientation (p1, p2, p) >= 0.) {
if (l1) l1->next = i; else f1->points = i;
l1 = i;
}
else {
if (l2) l2->next = i; else f2->points = i;
l2 = i;
}
i = i->next;
}
f->points = NULL;
*last1 = l1;
*last2 = l2;
}
/* cf. figure misc/swap.fig */
static void swap_if_in_circle (GtsFace * f1,
GtsVertex * v1,
GtsVertex * v2,
GtsVertex * v3,
GtsEdge * e1,
GtsEdge * e2,
GtsEdge * e3,
GtsSurface * surface)
{
GtsFace * f2;
GtsEdge * e4, *e5;
GtsVertex * v4;
if (GTS_IS_CONSTRAINT (e1)) /* @e1 is a constraint can not swap */
return;
f2 = neighbor (f1, e1, surface);
if (f2 == NULL) /* @e1 is a boundary of @surface */
return;
if (GTS_TRIANGLE (f2)->e1 == e1) {
e4 = GTS_TRIANGLE (f2)->e2; e5 = GTS_TRIANGLE (f2)->e3;
}
else if (GTS_TRIANGLE (f2)->e2 == e1) {
e4 = GTS_TRIANGLE (f2)->e3; e5 = GTS_TRIANGLE (f2)->e1;
}
else {
e4 = GTS_TRIANGLE (f2)->e1; e5 = GTS_TRIANGLE (f2)->e2;
}
if (GTS_SEGMENT (e4)->v1 == GTS_SEGMENT (e1)->v1 ||
GTS_SEGMENT (e4)->v1 == GTS_SEGMENT (e1)->v2)
v4 = GTS_SEGMENT (e4)->v2;
else
v4 = GTS_SEGMENT (e4)->v1;
if (gts_point_in_circle (GTS_POINT (v4), GTS_POINT (v1),
GTS_POINT (v2), GTS_POINT (v3)) > 0.0) {
GtsEdge * en;
GtsSegment * sn = gts_vertices_are_connected (v3, v4);
GtsFace * f3, * f4;
if (!GTS_IS_EDGE (sn))
en = gts_edge_new (surface->edge_class, v3, v4);
else
en = GTS_EDGE (sn);
f3 = gts_face_new (surface->face_class, en, e5, e2);
gts_object_attributes (GTS_OBJECT (f3), GTS_OBJECT (f1));
f4 = gts_face_new (surface->face_class, en, e3, e4);
gts_object_attributes (GTS_OBJECT (f4), GTS_OBJECT (f2));
if (GTS_IS_LIST_FACE (f3)) {
GSList * last3 = NULL, * last4 = NULL;
if (GTS_IS_LIST_FACE (f1))
split_list (GTS_LIST_FACE (f1), GTS_LIST_FACE (f3), GTS_LIST_FACE (f4),
GTS_POINT (v3), GTS_POINT (v4), &last3, &last4);
if (GTS_IS_LIST_FACE (f2))
split_list (GTS_LIST_FACE (f2), GTS_LIST_FACE (f3), GTS_LIST_FACE (f4),
GTS_POINT (v3), GTS_POINT (v4), &last3, &last4);
if (last3) last3->next = NULL;
if (last4) last4->next = NULL;
}
gts_surface_remove_face (surface, f1);
gts_surface_remove_face (surface, f2);
gts_surface_add_face (surface, f3);
gts_surface_add_face (surface, f4);
swap_if_in_circle (f3, v4, v2, v3, e5, e2, en, surface);
swap_if_in_circle (f4, v1, v4, v3, e4, en, e3, surface);
}
}
/**
* gts_delaunay_add_vertex_to_face:
* @surface: a #GtsSurface.
* @v: a #GtsVertex.
* @f: a #GtsFace belonging to @surface.
*
* Adds vertex @v to the face @f of the Delaunay triangulation defined
* by @surface.
*
* Returns: %NULL is @v has been successfully added to @surface or was
* already contained in @surface or a #GtsVertex having the same x and
* y coordinates as @v.
*/
GtsVertex * gts_delaunay_add_vertex_to_face (GtsSurface * surface,
GtsVertex * v,
GtsFace * f)
{
GtsEdge * e1, * e2, * e3;
GtsSegment * s4, * s5, * s6;
GtsEdge * e4, * e5, * e6;
GtsVertex * v1, * v2, * v3;
GtsFace * nf[3];
g_return_val_if_fail (surface != NULL, v);
g_return_val_if_fail (v != NULL, v);
g_return_val_if_fail (f != NULL, v);
gts_triangle_vertices_edges (GTS_TRIANGLE (f), NULL,
&v1, &v2, &v3, &e1, &e2, &e3);
if (v == v1 || v == v2 || v == v3) /* v already in @surface */
return NULL;
if (GTS_POINT (v)->x == GTS_POINT (v1)->x &&
GTS_POINT (v)->y == GTS_POINT (v1)->y)
return v1;
if (GTS_POINT (v)->x == GTS_POINT (v2)->x &&
GTS_POINT (v)->y == GTS_POINT (v2)->y)
return v2;
if (GTS_POINT (v)->x == GTS_POINT (v3)->x &&
GTS_POINT (v)->y == GTS_POINT (v3)->y)
return v3;
s4 = gts_vertices_are_connected (v, v1);
if (!GTS_IS_EDGE (s4))
e4 = gts_edge_new (surface->edge_class, v, v1);
else
e4 = GTS_EDGE (s4);
s5 = gts_vertices_are_connected (v, v2);
if (!GTS_IS_EDGE (s5))
e5 = gts_edge_new (surface->edge_class, v, v2);
else
e5 = GTS_EDGE (s5);
s6 = gts_vertices_are_connected (v, v3);
if (!GTS_IS_EDGE (s6))
e6 = gts_edge_new (surface->edge_class, v, v3);
else
e6 = GTS_EDGE (s6);
/* cf. figure misc/swap.fig */
nf[0] = gts_face_new (surface->face_class, e4, e1, e5);
gts_object_attributes (GTS_OBJECT (nf[0]), GTS_OBJECT (f));
nf[1] = gts_face_new (surface->face_class, e5, e2, e6);
gts_object_attributes (GTS_OBJECT (nf[1]), GTS_OBJECT (f));
nf[2] = gts_face_new (surface->face_class, e6, e3, e4);
gts_object_attributes (GTS_OBJECT (nf[2]), GTS_OBJECT (f));
if (GTS_IS_LIST_FACE (f) && GTS_IS_LIST_FACE (nf[0])) {
GSList * i = GTS_LIST_FACE (f)->points, * last[3] = { NULL, NULL, NULL };
while (i) {
GtsPoint * p = i->data;
GSList * next = i->next;
guint j;
if (p != GTS_POINT (v)) {
if (gts_point_orientation (GTS_POINT (v), GTS_POINT (v1), p) >= 0.) {
gdouble o = gts_point_orientation (GTS_POINT (v), GTS_POINT (v2), p);
if (o != 0.)
j = o > 0. ? 1 : 0;
else
j = gts_point_orientation (GTS_POINT (v), GTS_POINT (v3), p)
> 0. ? 0 : 1;
}
else if (gts_point_orientation (GTS_POINT (v), GTS_POINT (v3), p) > 0.)
j = 2;
else
j = 1;
if (last[j])
last[j]->next = i;
else
GTS_LIST_FACE (nf[j])->points = i;
last[j] = i;
}
else
g_slist_free_1 (i);
i = next;
}
GTS_LIST_FACE (f)->points = NULL;
if (last[0]) last[0]->next = NULL;
if (last[1]) last[1]->next = NULL;
if (last[2]) last[2]->next = NULL;
}
gts_surface_remove_face (surface, f);
gts_surface_add_face (surface, nf[0]);
gts_surface_add_face (surface, nf[1]);
gts_surface_add_face (surface, nf[2]);
swap_if_in_circle (nf[0], v1, v2, v, e1, e5, e4, surface);
swap_if_in_circle (nf[1], v2, v3, v, e2, e6, e5, surface);
swap_if_in_circle (nf[2], v3, v1, v, e3, e4, e6, surface);
return NULL;
}
/**
* gts_delaunay_add_vertex:
* @surface: a #GtsSurface.
* @v: a #GtsVertex.
* @guess: %NULL or a #GtsFace belonging to @surface to be used as an initial
* guess for point location.
*
* Adds vertex @v to the Delaunay triangulation defined by
* @surface. If @v is not contained in the convex hull bounding
* @surface, @v is not added to the triangulation.
*
* Returns: %NULL is @v has been successfully added to @surface or was
* already contained in @surface, @v if @v is not contained in the
* convex hull bounding surface or a #GtsVertex having the same x and
* y coordinates as @v.
*/
GtsVertex * gts_delaunay_add_vertex (GtsSurface * surface,
GtsVertex * v,
GtsFace * guess)
{
GtsFace * f;
g_return_val_if_fail (surface != NULL, v);
g_return_val_if_fail (v != NULL, v);
if (!(f = gts_point_locate (GTS_POINT (v), surface, guess)))
return v;
return gts_delaunay_add_vertex_to_face (surface, v, f);
}
static gboolean polygon_in_circle (GSList * poly,
GtsPoint * p1,
GtsPoint * p2,
GtsPoint * p3)
{
GtsVertex * v1 = NULL, * v2 = NULL;
while (poly) {
GtsSegment * s = poly->data;
GtsVertex * v;
v = s->v1;
if (v != v1 && v != v2 &&
v != GTS_VERTEX (p1) &&
v != GTS_VERTEX (p2) &&
v != GTS_VERTEX (p3) &&
gts_point_in_circle (GTS_POINT (v), p1, p2, p3) > 0.)
return TRUE;
v = s->v2;
if (v != v1 && v != v2 &&
v != GTS_VERTEX (p1) &&
v != GTS_VERTEX (p2) &&
v != GTS_VERTEX (p3) &&
gts_point_in_circle (GTS_POINT (v), p1, p2, p3) > 0.)
return TRUE;
v1 = s->v1;
v2 = s->v2;
poly = poly->next;
}
return FALSE;
}
static void triangulate_polygon (GSList * poly,
GtsSurface * surface,
GtsFace * ref)
{
GSList * i, * poly1, * poly2;
GtsVertex * v1, * v2, * v3 = NULL;
gboolean found = FALSE;
GtsSegment * s, * s1, * s2;
GtsEdge * e1, * e2;
GtsFace * f;
if (poly == NULL || poly->next == NULL) {
g_slist_free (poly);
return;
}
s = poly->data;
s1 = poly->next->data;
if (s->v1 == s1->v1 || s->v1 == s1->v2) {
v1 = s->v2;
v2 = s->v1;
}
else {
g_assert (s->v2 == s1->v1 || s->v2 == s1->v2);
v1 = s->v1;
v2 = s->v2;
}
i = poly->next;
v3 = v2;
while (i && !found) {
s1 = i->data;
if (s1->v1 == v3)
v3 = s1->v2;
else {
g_assert (s1->v2 == v3);
v3 = s1->v1;
}
if (v3 != v1 &&
gts_point_orientation (GTS_POINT (v1),
GTS_POINT (v2),
GTS_POINT (v3)) >= 0. &&
!polygon_in_circle (poly,
GTS_POINT (v1),
GTS_POINT (v2),
GTS_POINT (v3)))
found = TRUE;
else
i = i->next;
}
if (!found) {
g_slist_free (poly);
return;
}
s1 = gts_vertices_are_connected (v2, v3);
if (!GTS_IS_EDGE (s1))
e1 = gts_edge_new (surface->edge_class, v2, v3);
else
e1 = GTS_EDGE (s1);
s2 = gts_vertices_are_connected (v3, v1);
if (!GTS_IS_EDGE (s2))
e2 = gts_edge_new (surface->edge_class, v3, v1);
else
e2 = GTS_EDGE (s2);
f = gts_face_new (surface->face_class, GTS_EDGE (s), e1, e2);
gts_object_attributes (GTS_OBJECT (f), GTS_OBJECT (ref));
gts_surface_add_face (surface, f);
poly1 = poly->next;
g_slist_free_1 (poly);
if (i->next && e2 != i->next->data)
poly2 = g_slist_prepend (i->next, e2);
else
poly2 = i->next;
if (e1 != i->data)
i->next = g_slist_prepend (NULL, e1);
else
i->next = NULL;
triangulate_polygon (poly1, surface, ref);
triangulate_polygon (poly2, surface, ref);
}
/**
* gts_delaunay_remove_vertex:
* @surface: a #GtsSurface.
* @v: a #GtsVertex.
*
* Removes @v from the Delaunay triangulation defined by @surface and
* restores the Delaunay property. Vertex @v must not be used by any
* constrained edge otherwise the triangulation is not guaranteed to
* be Delaunay.
*/
void gts_delaunay_remove_vertex (GtsSurface * surface, GtsVertex * v)
{
GSList * triangles, * i;
GtsFace * ref = NULL;
g_return_if_fail (surface != NULL);
g_return_if_fail (v != NULL);
i = triangles = gts_vertex_triangles (v, NULL);
while (i && !ref) {
if (GTS_IS_FACE (i->data) &&
gts_face_has_parent_surface (i->data, surface))
ref = i->data;
i = i->next;
}
if (!ref) {
g_slist_free (triangles);
g_return_if_fail (ref);
}
triangulate_polygon (gts_vertex_fan_oriented (v, surface), surface, ref);
i = triangles;
while (i) {
if (GTS_IS_FACE (i->data) &&
gts_face_has_parent_surface (i->data, surface))
gts_surface_remove_face (surface, i->data);
i = i->next;
}
g_slist_free (triangles);
}
#define NEXT_CUT(edge, edge1, list) { next = neighbor (f, edge, surface);\
remove_triangles (e, surface);\
if (!constraint && !e->triangles)\
gts_object_destroy (GTS_OBJECT (e));\
g_assert (next);\
*list = g_slist_prepend (*list, edge1);\
return g_slist_concat (constraint,\
remove_intersected_edge (s, edge,\
next, surface, left, right));\
}
static void remove_triangles (GtsEdge * e, GtsSurface * s)
{
GSList * i = e->triangles;
while (i) {
GSList * next = i->next;
if (GTS_IS_FACE (i->data) && gts_face_has_parent_surface (i->data, s))
gts_surface_remove_face (s, i->data);
i = next;
}
}
static GSList *
remove_intersected_edge (GtsSegment * s,
GtsEdge * e,
GtsFace * f,
GtsSurface * surface,
GSList ** left, GSList ** right)
{
GtsVertex * v1, * v2, * v3;
GtsEdge * e1, * e2;
gdouble o1, o2;
GtsFace * next;
GSList * constraint = NULL;
if (GTS_IS_CONSTRAINT (e))
constraint = g_slist_prepend (NULL, e);
gts_triangle_vertices_edges (GTS_TRIANGLE (f), e,
&v1, &v2, &v3, &e, &e1, &e2);
o1 = gts_point_orientation (GTS_POINT (v2), GTS_POINT (v3),
GTS_POINT (s->v2));
o2 = gts_point_orientation (GTS_POINT (v3), GTS_POINT (v1),
GTS_POINT (s->v2));
if (o1 == 0. && o2 == 0.) {
/* if(o2 != 0.) {
fprintf(stderr, "o1 = %f o2 = %f\n", o1, o2);
fprintf(stderr, "v1 = %f, %f\n", GTS_POINT(v1)->x, GTS_POINT(v1)->y);
fprintf(stderr, "v2 = %f, %f\n", GTS_POINT(v2)->x, GTS_POINT(v2)->y);
fprintf(stderr, "v3 = %f, %f\n", GTS_POINT(v3)->x, GTS_POINT(v3)->y);
fprintf(stderr, "s->v2 = %f, %f\n", GTS_POINT(s->v2)->x, GTS_POINT(s->v2)->y);
g_assert (o2 == 0.);
}*/
// if(o2 == 0.) {
remove_triangles (e, surface);
if (!constraint && !e->triangles)
gts_object_destroy (GTS_OBJECT (e));
*left = g_slist_prepend (*left, e2);
*right = g_slist_prepend (*right, e1);
// }
}
else if (o1 > 0.) {
g_assert (o2 <= 0.);
NEXT_CUT (e2, e1, right)
}
else if (o2 >= 0.)
NEXT_CUT (e1, e2, left)
else {
gdouble o3 = gts_point_orientation (GTS_POINT (s->v1), GTS_POINT (s->v2),
GTS_POINT (v3));
if (o3 > 0.)
NEXT_CUT (e1, e2, left)
else
NEXT_CUT (e2, e1, right)
}
return constraint;
}
static GSList *
remove_intersected_vertex (GtsSegment * s,
GtsVertex * v,
GtsSurface * surface,
GSList ** left,
GSList ** right,
GtsFace ** ref)
{
GSList * triangles = gts_vertex_triangles (v, NULL);
GSList * i;
i = triangles;
while (i) {
GtsTriangle * t = i->data;
if (GTS_IS_FACE (t) &&
gts_face_has_parent_surface (GTS_FACE (t), surface)) {
GtsVertex * v1, * v2, * v3;
gdouble o1, o2;
gts_triangle_vertices (t, &v1, &v2, &v3);
if (v == v2) {
v2 = v3;
v3 = v1;
}
else if (v == v3) {
v3 = v2;
v2 = v1;
}
else
g_assert (v == v1);
if ((o1 = gts_point_orientation (GTS_POINT (v), GTS_POINT (v2),
GTS_POINT (s->v2))) >= 0. &&
(o2 = gts_point_orientation (GTS_POINT (v3), GTS_POINT (v),
GTS_POINT (s->v2))) >= 0.) {
gdouble o3 = gts_point_orientation (GTS_POINT (v2), GTS_POINT (v3),
GTS_POINT (s->v2));
GtsEdge * e = gts_triangle_edge_opposite (t, v);
GtsEdge * e1, * e2;
GtsFace * next = neighbor (GTS_FACE (t), e, surface);
*ref = GTS_FACE (t);
gts_triangle_vertices_edges (t, e, &v2, &v3, &v, &e, &e2, &e1);
g_slist_free (triangles);
if (o3 >= 0.) /* @s->v2 is inside (or on the edge) of t */
return NULL;
gts_allow_floating_faces = TRUE;
gts_surface_remove_face (surface, GTS_FACE (t));
gts_allow_floating_faces = FALSE;
*left = g_slist_prepend (*left, e2);
*right = g_slist_prepend (*right, e1);
g_assert (next);
return remove_intersected_edge (s, e, next, surface, left, right);
}
}
i = i->next;
}
g_assert_not_reached ();
return NULL;
}
/**
* gts_delaunay_add_constraint:
* @surface: a #GtsSurface.
* @c: a #GtsConstraint.
*
* Add constraint @c to the constrained Delaunay triangulation defined by
* @surface.
*
* Returns: a list of #GtsConstraint conflicting (i.e. intersecting) with @c
* which were removed from @surface (%NULL if there was none).
*/
GSList * gts_delaunay_add_constraint (GtsSurface * surface,
GtsConstraint * c)
{
GSList * constraints;
GtsVertex * v1; //, * v2;
GSList * left = NULL, * right = NULL;
GtsFace * ref = NULL;
g_return_val_if_fail (surface != NULL, NULL);
g_return_val_if_fail (c != NULL, NULL);
g_return_val_if_fail (GTS_IS_CONSTRAINT (c), NULL);
v1 = GTS_SEGMENT (c)->v1;
//v2 = GTS_SEGMENT (c)->v2;
gts_allow_floating_edges = TRUE;
constraints = remove_intersected_vertex (GTS_SEGMENT (c), v1, surface,
&left, &right, &ref);
gts_allow_floating_edges = FALSE;
#if 1
triangulate_polygon (g_slist_prepend (g_slist_reverse (right), c),
surface, ref);
triangulate_polygon (g_slist_prepend (left, c),
surface, ref);
#else
right = g_slist_prepend (g_slist_reverse (right), c);
left = g_slist_prepend (left, c);
{