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improve sweeping a little

This commit is contained in:
kanhuang 2013-09-11 20:49:50 -04:00
parent a730c197c8
commit c99a8954ec
1 changed files with 58 additions and 25 deletions
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83
Visibility_2/include/CGAL/Rotational_sweep_visibility_2.h
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@ -399,58 +399,91 @@ private:
//angular sweep begins
for (int i=0; i!=vs.size(); i++) {
dp = vs[i];
Point_2 v = dp;
Pair closest_e = heap.front(); //save the closest edge;
int insert_cnt(0), remove_cnt(0);
Point_2 p_remove, p_insert;
for (int j=0; j!=neighbors[v].size(); j++) {
Pair e = create_pair(v, neighbors[v][j]);
if (edx.count(e)) {
p_remove = neighbors[v][j];
std::vector<Point_2>& neis=neighbors[dp];
std::vector<Point_2> insert_ps, remove_ps;
for (int j=0; j!=neis.size(); j++) {
Point_2& nei= neis[j];
// Orientation o=Visibility_2::orientation_2(geom_traits, q, dp, nei);
/* if (o==RIGHT_TURN ||
(o==COLLINEAR && i>0 && Visibility_2::compare_xy_2(geom_traits, nei, vs[i-1])==EQUAL))*/
if (edx.count(create_pair(dp, nei))){
remove_ps.push_back(nei);
remove_cnt++;
}
else {
p_insert = neighbors[v][j];
insert_ps.push_back(nei);
insert_cnt++;
}
}
if (remove_cnt == 1 && insert_cnt == 1) {
//it's a special case that one edge is removed and one is inserted.
//just replace the old one by the new one. no heap operation is needed.
Pair e_out = create_pair(v, p_remove);
Pair e_in = create_pair(v, p_insert);
if (remove_ps.size()==1 && insert_ps.size()==1) {
Pair e_out = create_pair(dp, remove_ps.front());
Pair e_in = create_pair(dp, insert_ps.front());
heap[edx[e_out]] = e_in;
edx[e_in] = edx[e_out];
edx.erase(e_out);
}
else {
for (int j=0; j!=neighbors[v].size(); j++) {
Pair e = create_pair(v, neighbors[v][j]);
if (edx.count(e)) {
heap_remove(edx[e]);
remove_cnt++;
}
else {
heap_insert(e);
insert_cnt++;
}
for (int j=0; j!=remove_ps.size(); j++) {
heap_remove(edx[create_pair(dp, remove_ps[j])]);
}
for (int j=0; j!=insert_ps.size(); j++) {
heap_insert(create_pair(dp, insert_ps[j]));
}
}
// Point_2 p_remove, p_insert;
// for (int j=0; j!=neighbors[v].size(); j++) {
// Pair e = create_pair(v, neighbors[v][j]);
// if (edx.count(e)) {
// p_remove = neighbors[v][j];
// remove_cnt++;
// }
// else {
// p_insert = neighbors[v][j];
// insert_cnt++;
// }
// }
// if (remove_cnt == 1 && insert_cnt == 1) {
// //it's a special case that one edge is removed and one is inserted.
// //just replace the old one by the new one. no heap operation is needed.
// Pair e_out = create_pair(v, p_remove);
// Pair e_in = create_pair(v, p_insert);
// heap[edx[e_out]] = e_in;
// edx[e_in] = edx[e_out];
// edx.erase(e_out);
// }
// else {
// for (int j=0; j!=neighbors[v].size(); j++) {
// Pair e = create_pair(v, neighbors[v][j]);
// if (edx.count(e)) {
// heap_remove(edx[e]);
// }
// else {
// heap_insert(e);
// }
// }
// }
if (closest_e != heap.front()) {
//when the closest edge changed
if (remove_cnt > 0 && insert_cnt > 0) {
//some edges are added and some are deleted, which means the vertice sweeped is a vertice of visibility polygon.
update_visibility(v);
update_visibility(dp);
}
if (remove_cnt == 0 && insert_cnt > 0) {
//only add some edges, means the view ray is blocked by new edges.
//therefore first add the intersection of view ray and former closet edge, then add the vertice sweeped.
update_visibility(ray_seg_intersection(q, dp, closest_e.first, closest_e.second));
update_visibility(v);
update_visibility(dp);
}
if (remove_cnt > 0 && insert_cnt == 0) {
//only delete some edges, means some block is moved and the view ray can reach the segments after the block.
update_visibility(v);
update_visibility(dp);
update_visibility(ray_seg_intersection(q, dp, heap.front().first, heap.front().second));
}
}