static GLenum
verify_edge_vertex_intersections(GLUtriangulatorObj * tobj)
{
tess_polygon *polygon = tobj->current_polygon;
tess_vertex *vertex1, *last_vertex, *vertex2;
GLenum test;
last_vertex = polygon->last_vertex;
vertex1 = last_vertex;
for (vertex2 = vertex1->next->next;
vertex2->next != last_vertex; vertex2 = vertex2->next) {
test = edge_edge_intersect(vertex1, vertex1->next, vertex2,
vertex2->next);
if (test != GLU_NO_ERROR) {
tess_call_user_error(tobj, test);
return GLU_ERROR;
}
}
for (vertex1 = polygon->vertices;
vertex1->next->next != last_vertex; vertex1 = vertex1->next) {
for (vertex2 = vertex1->next->next;
vertex2 != last_vertex; vertex2 = vertex2->next) {
test = edge_edge_intersect(vertex1, vertex1->next, vertex2,
vertex2->next);
if (test != GLU_NO_ERROR) {
tess_call_user_error(tobj, test);
return GLU_ERROR;
}
}
}
return GLU_NO_ERROR;
}
// TODO: pass vectors
bool Circle::edge_polygon_intersect(Vector2 e1, Vector2 e2)
{
for (size_t i = 0; i < num_points; i++)
{
Vector2 p = pts[i];
Vector2 q = pts[(i + 1) % num_points];
if (edge_edge_intersect(e1.x, e1.y, e2.x, e2.y, p.x, p.y, q.x, p.y))
{
return true;
}
}
return false;
}
static GLenum
contours_overlap(tess_contour * contour, tess_polygon * polygon)
{
tess_vertex *vertex1, *vertex2;
GLuint vertex1_cnt, vertex2_cnt, i, j;
GLenum test;
vertex1 = contour->vertices;
vertex2 = polygon->vertices;
vertex1_cnt = contour->vertex_cnt;
vertex2_cnt = polygon->vertex_cnt;
for (i = 0; i < vertex1_cnt; vertex1 = vertex1->next, i++) {
for (j = 0; j < vertex2_cnt; vertex2 = vertex2->next, j++)
if ((test = edge_edge_intersect(vertex1, vertex1->next, vertex2,
vertex2->next)) != GLU_NO_ERROR)
return test;
}
return GLU_NO_ERROR;
}
static GLenum
cut_out_hole(GLUtriangulatorObj * tobj,
tess_contour * contour, tess_contour * hole)
{
tess_contour *tmp_hole;
tess_vertex *v1, *v2, *tmp_vertex;
GLuint vertex1_cnt, vertex2_cnt, tmp_vertex_cnt;
GLuint i, j, k;
GLenum test = 0;
/* find an edge connecting contour and hole not intersecting any other */
/* edge belonging to either the contour or any of the other holes */
for (v1 = contour->vertices, vertex1_cnt = contour->vertex_cnt, i = 0;
i < vertex1_cnt; i++, v1 = v1->next) {
for (v2 = hole->vertices, vertex2_cnt = hole->vertex_cnt, j = 0;
j < vertex2_cnt; j++, v2 = v2->next) {
/* does edge (v1,v2) intersect any edge of contour */
for (tmp_vertex = contour->vertices, tmp_vertex_cnt =
contour->vertex_cnt, k = 0; k < tmp_vertex_cnt;
tmp_vertex = tmp_vertex->next, k++) {
/* skip edge tests for edges directly connected */
if (v1 == tmp_vertex || v1 == tmp_vertex->next)
continue;
test = edge_edge_intersect(v1, v2, tmp_vertex, tmp_vertex->next);
if (test != GLU_NO_ERROR)
break;
}
if (test == GLU_NO_ERROR) {
/* does edge (v1,v2) intersect any edge of hole */
for (tmp_vertex = hole->vertices,
tmp_vertex_cnt = hole->vertex_cnt, k = 0;
k < tmp_vertex_cnt; tmp_vertex = tmp_vertex->next, k++) {
/* skip edge tests for edges directly connected */
if (v2 == tmp_vertex || v2 == tmp_vertex->next)
continue;
test =
edge_edge_intersect(v1, v2, tmp_vertex, tmp_vertex->next);
if (test != GLU_NO_ERROR)
break;
}
if (test == GLU_NO_ERROR) {
/* does edge (v1,v2) intersect any other hole? */
for (tmp_hole = hole->next;
tmp_hole != NULL && tmp_hole->type == GLU_INTERIOR;
tmp_hole = tmp_hole->next) {
/* does edge (v1,v2) intersect any edge of hole */
for (tmp_vertex = tmp_hole->vertices,
tmp_vertex_cnt = tmp_hole->vertex_cnt, k = 0;
k < tmp_vertex_cnt; tmp_vertex = tmp_vertex->next, k++) {
test = edge_edge_intersect(v1, v2, tmp_vertex,
tmp_vertex->next);
if (test != GLU_NO_ERROR)
break;
}
if (test != GLU_NO_ERROR)
break;
}
}
}
if (test == GLU_NO_ERROR) {
/* edge (v1,v2) is good for eliminating the hole */
if (merge_hole_with_contour(tobj, contour, hole, v1, v2)
== GLU_NO_ERROR)
return GLU_NO_ERROR;
else
return GLU_ERROR;
}
}
}
/* other holes are blocking all possible connections of hole */
/* with contour, we shift this hole as the last hole and retry */
for (tmp_hole = hole;
tmp_hole != NULL && tmp_hole->type == GLU_INTERIOR;
tmp_hole = tmp_hole->next);
contour->next = hole->next;
hole->next->previous = contour;
if (tmp_hole == NULL) {
/* last EXTERIOR contour, shift hole as last contour */
hole->next = NULL;
hole->previous = tobj->last_contour;
tobj->last_contour->next = hole;
tobj->last_contour = hole;
}
else {
tmp_hole->previous->next = hole;
hole->previous = tmp_hole->previous;
tmp_hole->previous = hole;
hole->next = tmp_hole;
}
hole = contour->next;
/* try once again - recurse */
return cut_out_hole(tobj, contour, hole);
}