// find the cycles representing each polygon in the layer
// this is a naive O(n^2) implementaion, it will benefit greatly from a scanline aproach
void Layer::create_polys() {
std::vector<line*> candidates (segments->begin(), segments->end());
while (!candidates.empty()) {
line *cur_start = candidates.at(0);
point *poly_start = &(cur_start->p1);
point *look_for = &(cur_start->p2);
// REMOVE the start poly from the candidates
candidates.erase(candidates.begin());
std::vector<point*> *cur_poly = new std::vector<point*>;
cur_poly->push_back(poly_start);
// follow this polygon around
while ( !point_compare(*look_for, *poly_start) ) {
// If there are not exact match we have to find a best match
int closest_idx = -42;
double closest_distanceSQ = 42;
int cur_idx=0;
for(std::vector<line*>::iterator it = candidates.begin(); it != candidates.end(); it++) {
line *l = *it;
if (point_compare(l->p1, *look_for)) {
// we found the other end
cur_poly->push_back(look_for);
// update what wer are looking
look_for = &(l->p2);
// never look at this again.
candidates.erase(it);
closest_distanceSQ = 0.0;
closest_idx = cur_idx;
break;
}
double cur_disSQ = point_distSQ(*look_for, l->p1);
if (cur_disSQ < closest_distanceSQ ) {
closest_idx = cur_idx;
closest_distanceSQ = cur_disSQ;
}
cur_idx++;
}
if (closest_distanceSQ != 0.0) {
// we did not find a match take the best..
printf("not exact match\n");
*look_for = candidates[closest_idx]->p2;
candidates.erase(candidates.begin()+closest_idx);
}
}
// there should be a cycle, insert look_for ? and
poly->push_back(*cur_poly);
}
}
static int
compare_point_to_tile(void const *key, void const *object)
{
struct point const *point = key;
struct tile *const *tile = object;
return point_compare(*point, (*tile)->point);
}
static int
compare_by_point(void const *object, void const *other_object)
{
struct tile *const *tile = object;
struct tile *const *other = other_object;
return point_compare((*tile)->point, (*other)->point);
}
int
main(int argc, char **argv)
{
struct point p1, *p2;
point_set(&p1, 1.0, 1.0);
p2 = malloc(sizeof(struct point));
assert(p2);
point_set(p2, 1.0, 1.0);
assert(point_distance(&p1, p2) == 0.0);
point_translate(&p1, 1.0, 0.0);
assert(point_distance(&p1, p2) == 1.0);
point_set(&p1, 0.0, 0.0);
point_set(p2, 3.0, 4.0);
assert(point_distance(&p1, p2) == 5.0);
assert(point_compare(&p1, p2) < 0);
point_set(&p1, 1, 2);
point_set(p2, 2, 1);
assert(point_compare(&p1, p2) == 0);
point_set(&p1, 4, 2);
point_set(p2, 3, 3);
assert(point_compare(&p1, p2) > 0);
free(p2);
p2 = NULL;
printf("OK\n");
return 0;
}
