static void add_constraint (GtsConstraint * c, GtsSurface * s)
{
g_assert (gts_delaunay_add_constraint (s, c) == NULL);
}
static GtsSurface * cartesian_grid_triangulate_holes (CartesianGrid * grid,
GtsSurface * s)
{
GtsVertex * v1, * v2, * v3, * v4;
GtsEdge * e1, * e2, * e3, * e4, * e5;
gdouble w, h;
GtsSurface * box;
GSList * constraints = NULL, * vertices = NULL, * i;
gpointer data[2];
g_return_val_if_fail (grid != NULL, NULL);
g_return_val_if_fail (s != NULL, NULL);
/* build enclosing box */
w = grid->xmax - grid->xmin;
h = grid->ymax - grid->ymin;
v1 = gts_vertex_new (s->vertex_class, grid->xmin - w, grid->ymin - h, 0.);
v2 = gts_vertex_new (s->vertex_class, grid->xmax + w, grid->ymin - h, 0.);
v3 = gts_vertex_new (s->vertex_class, grid->xmax + w, grid->ymax + h, 0.);
v4 = gts_vertex_new (s->vertex_class, grid->xmin - w, grid->ymax + h, 0.);
e1 = gts_edge_new (s->edge_class, v1, v2);
e2 = gts_edge_new (s->edge_class, v2, v3);
e3 = gts_edge_new (s->edge_class, v3, v4);
e4 = gts_edge_new (s->edge_class, v4, v1);
e5 = gts_edge_new (s->edge_class, v1, v3);
box = gts_surface_new (GTS_SURFACE_CLASS (GTS_OBJECT (s)->klass),
s->face_class,
s->edge_class,
s->vertex_class);
gts_surface_add_face (box, gts_face_new (s->face_class, e1, e2, e5));
gts_surface_add_face (box, gts_face_new (s->face_class, e3, e4, e5));
/* build vertex and constraint list from the boundaries of the input
surface s */
data[0] = s;
data[1] = &constraints;
gts_surface_foreach_edge (s, (GtsFunc) build_constraint_list, data);
vertices = gts_vertices_from_segments (constraints);
/* triangulate holes */
i = vertices;
while (i) {
g_assert (!gts_delaunay_add_vertex (box, i->data, NULL));
i = i->next;
}
g_slist_free (vertices);
i = constraints;
while (i) {
g_assert (!gts_delaunay_add_constraint (box, i->data));
i = i->next;
}
/* destroy corners of the enclosing box */
gts_allow_floating_vertices = TRUE;
gts_object_destroy (GTS_OBJECT (v1));
gts_object_destroy (GTS_OBJECT (v2));
gts_object_destroy (GTS_OBJECT (v3));
gts_object_destroy (GTS_OBJECT (v4));
gts_allow_floating_vertices = FALSE;
/* remove parts of the mesh which are not holes */
i = constraints;
while (i) {
edge_mark_as_hole (i->data, box);
i = i->next;
}
g_slist_free (constraints);
/* remove marked and duplicate faces */
gts_surface_foreach_face_remove (box, (GtsFunc) face_is_marked, NULL);
/* box now contains only the triangulated holes. */
return box;
}
/* tri:
* Main entry point to using GTS for triangulation.
* Input is npt points with x and y coordinates stored either separately
* in x[] and y[] (sepArr != 0) or consecutively in x[] (sepArr == 0).
* Optionally, the input can include nsegs line segments, whose endpoint
* indices are supplied in segs[2*i] and segs[2*i+1] yielding a constrained
* triangulation.
*
* The return value is the corresponding gts surface, which can be queries for
* the triangles and line segments composing the triangulation.
*/
static GtsSurface*
tri(double *x, double *y, int npt, int *segs, int nsegs, int sepArr)
{
int i;
GtsSurface *surface;
GVertex **vertices = N_GNEW(npt, GVertex *);
GtsEdge **edges = N_GNEW(nsegs, GtsEdge*);
GSList *list = NULL;
GtsVertex *v1, *v2, *v3;
GtsTriangle *t;
GtsVertexClass *vcl = (GtsVertexClass *) g_vertex_class();
GtsEdgeClass *ecl = GTS_EDGE_CLASS (gts_constraint_class ());
if (sepArr) {
for (i = 0; i < npt; i++) {
GVertex *p = (GVertex *) gts_vertex_new(vcl, x[i], y[i], 0);
p->idx = i;
vertices[i] = p;
}
}
else {
for (i = 0; i < npt; i++) {
GVertex *p = (GVertex *) gts_vertex_new(vcl, x[2*i], x[2*i+1], 0);
p->idx = i;
vertices[i] = p;
}
}
/* N.B. Edges need to be created here, presumably before the
* the vertices are added to the face. In particular, they cannot
* be added created and added vi gts_delaunay_add_constraint() below.
*/
for (i = 0; i < nsegs; i++) {
edges[i] = gts_edge_new(ecl,
(GtsVertex *) (vertices[ segs[ 2 * i]]),
(GtsVertex *) (vertices[ segs[ 2 * i + 1]]));
}
for (i = 0; i < npt; i++)
list = g_slist_prepend(list, vertices[i]);
t = gts_triangle_enclosing(gts_triangle_class(), list, 100.);
g_slist_free(list);
gts_triangle_vertices(t, &v1, &v2, &v3);
surface = gts_surface_new(gts_surface_class(),
(GtsFaceClass *) g_face_class(),
gts_edge_class(),
gts_vertex_class());
gts_surface_add_face(surface, gts_face_new(gts_face_class(),
t->e1, t->e2, t->e3));
for (i = 0; i < npt; i++) {
GtsVertex *v1 = (GtsVertex *) vertices[i];
GtsVertex *v = gts_delaunay_add_vertex(surface, v1, NULL);
/* if v != NULL, it is a previously added pt with the same
* coordinates as v1, in which case we replace v1 with v
*/
if (v) {
/* agerr (AGWARN, "Duplicate point %d %d\n", i, ((GVertex*)v)->idx); */
gts_vertex_replace (v1, v);
}
}
for (i = 0; i < nsegs; i++) {
gts_delaunay_add_constraint(surface,GTS_CONSTRAINT(edges[i]));
}
/* destroy enclosing triangle */
gts_allow_floating_vertices = TRUE;
gts_allow_floating_edges = TRUE;
/*
gts_object_destroy(GTS_OBJECT(v1));
gts_object_destroy(GTS_OBJECT(v2));
gts_object_destroy(GTS_OBJECT(v3));
*/
destroy(v1);
destroy(v2);
destroy(v3);
gts_allow_floating_edges = FALSE;
gts_allow_floating_vertices = FALSE;
if (nsegs)
delaunay_remove_holes(surface);
free (edges);
free(vertices);
return surface;
}
