/**
* gts_edge_belongs_to_tetrahedron:
* @e: a #GtsEdge.
*
* Returns: %TRUE if @e is used by faces forming a tetrahedron, %FALSE
* otherwise.
*/
gboolean gts_edge_belongs_to_tetrahedron (GtsEdge * e)
{
GSList * i;
GtsVertex * v1, * v2;
g_return_val_if_fail (e != NULL, FALSE);
v1 = GTS_SEGMENT (e)->v1;
v2 = GTS_SEGMENT (e)->v2;
i = e->triangles;
while (i) {
GtsEdge * e1, * e2;
GtsVertex * vt1;
GSList * j = i->next;
triangle_vertices_edges (i->data, e, &vt1, &e1, &e2);
while (j) {
GtsSegment * s5;
GtsEdge * e3, * e4;
GtsVertex * vt2;
triangle_vertices_edges (j->data, e, &vt2, &e3, &e4);
s5 = gts_vertices_are_connected (vt1, vt2);
if (GTS_IS_EDGE (s5) &&
gts_triangle_use_edges (e1, e3, GTS_EDGE (s5)) &&
gts_triangle_use_edges (e2, e4, GTS_EDGE (s5)))
return TRUE;
j = j->next;
}
i = i->next;
}
return FALSE;
}
/**
* gts_edge_is_duplicate:
* @e: a #GtsEdge.
*
* Returns: the first #GtsEdge different from @e which shares the
* same endpoints or %NULL if there is none.
*/
GtsEdge * gts_edge_is_duplicate (GtsEdge * e)
{
GSList * i;
GtsVertex * v2;
g_return_val_if_fail (e != NULL, NULL);
v2 = GTS_SEGMENT (e)->v2;
i = GTS_SEGMENT (e)->v1->segments;
if (GTS_SEGMENT (e)->v1 == v2) /* e is degenerate: special treatment */
while (i) {
GtsSegment * s = i->data;
if (s != GTS_SEGMENT (e) &&
GTS_IS_EDGE (s) &&
s->v1 == v2 && s->v2 == v2)
return GTS_EDGE (s);
i = i->next;
}
else /* e is not degenerate */
while (i) {
GtsSegment * s = i->data;
if (s != GTS_SEGMENT (e) &&
GTS_IS_EDGE (s) &&
(s->v1 == v2 || s->v2 == v2))
return GTS_EDGE (s);
i = i->next;
}
return NULL;
}
/**
* gts_edge_swap:
* @e: a #GtsEdge.
* @s: a #GtsSurface.
*
* Performs an "edge swap" on the two triangles sharing @e and
* belonging to @s.
*/
void gts_edge_swap (GtsEdge * e, GtsSurface * s)
{
GtsTriangle * t1 = NULL, * t2 = NULL, * t;
GtsFace * f;
GSList * i;
GtsVertex * v1, * v2, * v3, * v4, * v5, * v6;
GtsEdge * e1, * e2, * e3, * e4;
GtsSegment * v3v6;
g_return_if_fail (e != NULL);
g_return_if_fail (s != NULL);
i = e->triangles;
while (i) {
if (GTS_IS_FACE (i->data) && gts_face_has_parent_surface (i->data, s)) {
if (!t1)
t1 = i->data;
else if (!t2)
t2 = i->data;
else
g_return_if_fail (gts_edge_face_number (e, s) == 2);
}
i = i->next;
}
g_assert (t1 && t2);
gts_triangle_vertices_edges (t1, e, &v1, &v2, &v3, &e, &e1, &e2);
gts_triangle_vertices_edges (t2, e, &v4, &v5, &v6, &e, &e3, &e4);
g_assert (v2 == v4 && v1 == v5);
v3v6 = gts_vertices_are_connected (v3, v6);
if (!GTS_IS_EDGE (v3v6))
v3v6 = GTS_SEGMENT (gts_edge_new (s->edge_class, v3, v6));
f = gts_face_new (s->face_class, e1, GTS_EDGE (v3v6), e4);
if ((t = gts_triangle_is_duplicate (GTS_TRIANGLE (f))) &&
GTS_IS_FACE (t)) {
gts_object_destroy (GTS_OBJECT (f));
f = GTS_FACE (t);
}
gts_surface_add_face (s, f);
f = gts_face_new (s->face_class, GTS_EDGE (v3v6), e2, e3);
if ((t = gts_triangle_is_duplicate (GTS_TRIANGLE (f))) &&
GTS_IS_FACE (t)) {
gts_object_destroy (GTS_OBJECT (f));
f = GTS_FACE (t);
}
gts_surface_add_face (s, f);
gts_surface_remove_face (s, GTS_FACE (t1));
gts_surface_remove_face (s, GTS_FACE (t2));
}
static GtsEdge * new_edge (GtsVertex * v1, GtsVertex * v2)
{
GtsSegment * s = gts_vertices_are_connected (v1, v2);
return s == NULL ?
gts_edge_new (GTS_EDGE_CLASS (gts_constraint_class ()), v1, v2) :
GTS_EDGE (s);
}
static void edge_clone (GtsObject * clone, GtsObject * object)
{
(* GTS_OBJECT_CLASS (gts_edge_class ())->parent_class->clone) (clone,
object);
GTS_SEGMENT (clone)->v1 = GTS_SEGMENT (clone)->v2 = NULL;
GTS_EDGE (clone)->triangles = NULL;
}
/**
* gts_edges_from_vertices:
* @vertices: a list of #GtsVertex.
* @parent: a #GtsSurface.
*
* Returns: a list of unique #GtsEdge which have one of their vertices in
* @vertices and are used by a face of @parent.
*/
GSList * gts_edges_from_vertices (GSList * vertices, GtsSurface * parent)
{
GHashTable * hash;
GSList * edges = NULL, * i;
g_return_val_if_fail (parent != NULL, NULL);
hash = g_hash_table_new (NULL, NULL);
i = vertices;
while (i) {
GSList * j = GTS_VERTEX (i->data)->segments;
while (j) {
GtsSegment * s = j->data;
if (GTS_IS_EDGE (s) &&
gts_edge_has_parent_surface (GTS_EDGE (s), parent) &&
g_hash_table_lookup (hash, s) == NULL) {
edges = g_slist_prepend (edges, s);
g_hash_table_insert (hash, s, i);
}
j = j->next;
}
i = i->next;
}
g_hash_table_destroy (hash);
return edges;
}
static void edge_destroy (GtsObject * object)
{
GtsEdge * edge = GTS_EDGE (object);
GSList * i;
i = edge->triangles;
while (i) {
GSList * next = i->next;
gts_object_destroy (i->data);
i = next;
}
g_assert (edge->triangles == NULL);
(* GTS_OBJECT_CLASS (gts_edge_class ())->parent_class->destroy) (object);
}
/**
* gts_triangles_from_edges:
* @edges: a list of #GtsEdge.
*
* Builds a list of unique triangles which have one of their edges in @edges.
*
* Returns: the list of triangles.
*/
GSList * gts_triangles_from_edges (GSList * edges)
{
GHashTable * hash;
GSList * triangles = NULL, * i;
hash = g_hash_table_new (NULL, NULL);
i = edges;
while (i) {
GSList * j = GTS_EDGE (i->data)->triangles;
while (j) {
GtsTriangle * t = j->data;
if (g_hash_table_lookup (hash, t) == NULL) {
triangles = g_slist_prepend (triangles, t);
g_hash_table_insert (hash, t, i);
}
j = j->next;
}
i = i->next;
}
g_hash_table_destroy (hash);
return triangles;
}
static void gts_constraint_split (GtsConstraint * c,
GtsSurface * s,
GtsFifo * fifo)
{
GSList * i;
GtsVertex * v1, * v2;
GtsEdge * e;
g_return_if_fail (c != NULL);
g_return_if_fail (s != NULL);
v1 = GTS_SEGMENT (c)->v1;
v2 = GTS_SEGMENT (c)->v2;
e = GTS_EDGE (c);
i = e->triangles;
while (i) {
GtsFace * f = i->data;
if (GTS_IS_FACE (f) && gts_face_has_parent_surface (f, s)) {
GtsVertex * v = gts_triangle_vertex_opposite (GTS_TRIANGLE (f), e);
if (gts_point_orientation (GTS_POINT (v1),
GTS_POINT (v2),
GTS_POINT (v)) == 0.) {
GSList * j = e->triangles;
GtsFace * f1 = NULL;
GtsEdge * e1, * e2;
/* replaces edges with constraints */
gts_triangle_vertices_edges (GTS_TRIANGLE (f), e,
&v1, &v2, &v, &e, &e1, &e2);
if (!GTS_IS_CONSTRAINT (e1)) {
GtsEdge * ne1 =
gts_edge_new (GTS_EDGE_CLASS (GTS_OBJECT (c)->klass), v2, v);
gts_edge_replace (e1, ne1);
gts_object_destroy (GTS_OBJECT (e1));
e1 = ne1;
if (fifo) gts_fifo_push (fifo, e1);
}
if (!GTS_IS_CONSTRAINT (e2)) {
GtsEdge * ne2 =
gts_edge_new (GTS_EDGE_CLASS (GTS_OBJECT (c)->klass), v, v1);
gts_edge_replace (e2, ne2);
gts_object_destroy (GTS_OBJECT (e2));
e2 = ne2;
if (fifo) gts_fifo_push (fifo, e2);
}
/* look for face opposite */
while (j && !f1) {
if (GTS_IS_FACE (j->data) &&
gts_face_has_parent_surface (j->data, s))
f1 = j->data;
j = j->next;
}
if (f1) { /* c is not a boundary of s */
GtsEdge * e3, * e4, * e5;
GtsVertex * v3;
gts_triangle_vertices_edges (GTS_TRIANGLE (f1), e,
&v1, &v2, &v3, &e, &e3, &e4);
e5 = gts_edge_new (s->edge_class, v, v3);
gts_surface_add_face (s, gts_face_new (s->face_class, e5, e2, e3));
gts_surface_add_face (s, gts_face_new (s->face_class, e5, e4, e1));
gts_object_destroy (GTS_OBJECT (f1));
}
gts_object_destroy (GTS_OBJECT (f));
return;
}
}
i = i->next;
}
}
/**
* gts_edge_new:
* @klass: a #GtsEdgeClass.
* @v1: a #GtsVertex.
* @v2: a #GtsVertex.
*
* Returns: a new #GtsEdge linking @v1 and @v2.
*/
GtsEdge * gts_edge_new (GtsEdgeClass * klass,
GtsVertex * v1, GtsVertex * v2)
{
return GTS_EDGE (gts_segment_new (GTS_SEGMENT_CLASS (klass), v1, v2));
}