mirror of https://github.com/CGAL/cgal
Minor improvements to Cuboid/Tr computations
- Slight robustness improvements by storing in memory that the intersection points are by construction on the plane. - const& and such Pair programming w/ mgimeno!
This commit is contained in:
Mael Rouxel-Labbé
parent
16ee956bae
commit
b4fb7cb779
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@ -26,8 +26,9 @@
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#include <CGAL/kernel_basic.h>
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#include <CGAL/intersections.h>
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#include <vector>
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#include <iterator>
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#include <list>
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#include <vector>
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namespace CGAL {
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@ -38,49 +39,61 @@ namespace internal {
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//only work for convex polygons, but in here that's always the case
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template<class K>
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void clip_poly_halfspace(
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const std::vector<typename K::Point_3>& input,
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std::vector<typename K::Point_3>& polygon,
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const typename K::Plane_3& pl,
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std::vector<typename K::Point_3>& output)
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const K& k)
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{
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if(input.empty())
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if(polygon.empty())
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return;
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typedef typename K::Point_3 Point;
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typedef typename K::Plane_3 Plane;
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typedef typename K::Segment_3 S;
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typedef typename K::Segment_3 Segment;
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typedef typename Intersection_traits<K,
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CGAL::Plane_3<K>,
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CGAL::Segment_3<K> >::result_type SP_type;
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std::list<Point> p_list(input.begin(), input.end());
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auto it = p_list.begin();
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// Keep in memory which points we are going to delete later (newer intersection points
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// by construction will not be deleted)
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std::list<std::pair<Point, bool> > p_list;
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for(const Point& p : polygon)
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p_list.emplace_back(p, pl.has_on_positive_side(p));
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//corefine with plane.
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auto it = p_list.begin();
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while(it != p_list.end())
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{
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Point p = *it;
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++it;
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const Point& p1 = (it++)->first;
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if(it == p_list.end())
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break;
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if(do_intersect(S(p, *it), pl))
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const Point& p2 = it->first;
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const Segment seg = k.construct_segment_3_object()(p1, p2);
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if(do_intersect(seg, pl))
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{
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SP_type inter = typename K::Intersect_3()(S(p, *it), pl);
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SP_type inter = k.intersect_3_object()(seg, pl);
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if(inter)
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{
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Point* p_inter = boost::get<Point>(&*inter);
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if(p_inter
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&& *p_inter != p
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&& *p_inter != *it)
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p_list.insert(it, *p_inter);
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&& !(k.equal_3_object()(*p_inter, p1))
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&& !(k.equal_3_object()(*p_inter, p2)))
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{
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// 'false' because we know the intersection is by construction not on the positive side of the plane
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p_list.insert(it, std::make_pair(*p_inter, false));
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}
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}
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}
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}
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if(input.size() >2)
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if(polygon.size() > 2)
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{
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Point p2(p_list.front()),
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p1(p_list.back());
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S seg(p1, p2);
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const Point& p2 = p_list.front().first;
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const Point& p1 = p_list.back().first;
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const Segment seg(p1, p2);
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if(do_intersect(seg, pl))
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{
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SP_type inter = typename K::Intersect_3()(seg, pl);
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@ -88,25 +101,29 @@ void clip_poly_halfspace(
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{
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Point* p_inter = boost::get<Point>(&*inter);
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if(p_inter
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&& *p_inter != p1
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&& *p_inter != p2)
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p_list.push_back(*p_inter);
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&& !(k.equal_3_object()(*p_inter, p1))
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&& !(k.equal_3_object()(*p_inter, p2)))
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{
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// 'false' because we know the intersection is by construction not on the positive side of the plane
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p_list.emplace_back(*p_inter, false);
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}
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}
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}
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}
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//remove all points on positive side
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for(auto p_it = p_list.begin();
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p_it != p_list.end();)
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for(auto it = p_list.begin(); it != p_list.end();)
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{
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if(pl.has_on_positive_side(*p_it))
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p_it = p_list.erase(p_it);
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if(it->second)
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it = p_list.erase(it);
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else
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++p_it;
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++it;
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}
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for(auto p : p_list)
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output.push_back(p);
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// Update the polygon
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polygon.clear();
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for(const auto& pr : p_list)
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polygon.push_back(pr.first);
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}
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template <class K>
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@ -114,12 +131,12 @@ typename Intersection_traits<K, typename K::Iso_cuboid_3, typename K::Triangle_3
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intersection(
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const typename K::Iso_cuboid_3 &cub,
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const typename K::Triangle_3 &tr,
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const K&)
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const K& k)
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{
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typedef typename K::Point_3 Point;
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typedef typename K::Segment_3 Segment;
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typedef typename K::Triangle_3 Triangle;
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typedef typename K::Plane_3 Plane_3;
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typedef typename K::Plane_3 Plane;
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typedef std::vector<Point> Poly;
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typedef typename Intersection_traits<K,
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@ -127,30 +144,30 @@ intersection(
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CGAL::Triangle_3<K> >::result_type Res_type;
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//Lazy implem: clip 6 times the input triangle.
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Plane_3 planes[6];
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planes[0] = Plane_3(cub.vertex(0),
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cub.vertex(1),
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cub.vertex(5));
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Plane planes[6];
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planes[0] = Plane(cub.vertex(0),
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cub.vertex(1),
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cub.vertex(5));
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planes[1] = Plane_3(cub.vertex(0),
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cub.vertex(4),
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cub.vertex(3));
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planes[1] = Plane(cub.vertex(0),
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cub.vertex(4),
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cub.vertex(3));
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planes[2]=Plane_3(cub.vertex(0),
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planes[2] = Plane(cub.vertex(0),
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cub.vertex(3),
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cub.vertex(1));
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planes[3] = Plane_3(cub.vertex(7),
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cub.vertex(6),
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cub.vertex(1));
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planes[3] = Plane(cub.vertex(7),
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cub.vertex(6),
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cub.vertex(1));
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planes[4] = Plane_3(cub.vertex(7),
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cub.vertex(3),
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cub.vertex(4));
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planes[4] = Plane(cub.vertex(7),
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cub.vertex(3),
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cub.vertex(4));
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planes[5] = Plane_3(cub.vertex(7),
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cub.vertex(4),
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cub.vertex(6));
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planes[5] = Plane(cub.vertex(7),
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cub.vertex(4),
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cub.vertex(6));
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std::vector<Point> poly;
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poly.push_back(tr.vertex(0));
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@ -158,11 +175,7 @@ intersection(
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poly.push_back(tr.vertex(2));
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for (int i = 0; i < 6; ++i)
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{
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Poly clipped;
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clip_poly_halfspace<K>(poly, planes[i], clipped);
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poly = clipped;
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}
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clip_poly_halfspace<K>(poly, planes[i], k);
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switch(poly.size())
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{
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@ -184,7 +197,7 @@ intersection(
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case 3:
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{
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Triangle res = Triangle (poly[0], poly[1], poly[2]);
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Triangle res = Triangle(poly[0], poly[1], poly[2]);
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return Res_type(std::forward<Triangle>(res));
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}
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break;
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@ -205,6 +218,9 @@ intersection(
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{
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return intersection(cub, tr, k);
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}
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}}}
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} // namespace internal
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} // namespace Intersections
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} // namespace CGAL
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#endif // CGAL_INTERSECTIONS_3_INTERNAL_ISO_CUBOID_3_TRIANGLE_3_INTERSECTION_H
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