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Introduced is_to_left() for points and used it to handle intersection spoints on the boundary

This commit is contained in:
Efi Fogel 2025-10-21 14:49:42 +03:00
parent 8730763d39
commit e7682069fe
2 changed files with 79 additions and 6 deletions
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67
Arrangement_on_surface_2/include/CGAL/Arrangement_2/Arrangement_zone_2_impl.h
View File

@ -790,6 +790,60 @@ _is_to_right_impl(const Point_2& p, Halfedge_handle he,
return (m_geom_traits->compare_xy_2_object()(p, v_right->point()) == LARGER);
}
//! checks whether an point lies to the left of another point.
template <typename Arrangement, typename ZoneVisitor>
bool Arrangement_zone_2<Arrangement, ZoneVisitor>::
is_to_left_impl(const Point_2& p1, Arr_parameter_space ps1,
const Point_2& p2, Arr_parameter_space ps2,
Arr_all_sides_oblivious_tag) const {
auto cmp_xy = m_geom_traits->compare_xy_2_object();
return (cmp_xy(p2, p1) == SMALLER);
}
//! checks whether an point lies to the left of another point.
template <typename Arrangement, typename ZoneVisitor>
bool Arrangement_zone_2<Arrangement, ZoneVisitor>::
is_to_left_impl(const Point_2& p1, Arr_parameter_space ps1,
const Point_2& p2, Arr_parameter_space ps2,
Arr_has_identified_side_tag) const {
auto is_on_y_ident = m_geom_traits->is_on_y_identification_2_object();
if (is_on_y_ident(p1)) {
if (is_on_y_ident(p2)) {
auto cmp_y_on_boundary = m_geom_traits->compare_y_on_boundary_2_object();
return (cmp_y_on_boundary(p2, p1) == SMALLER);
}
return false;
}
if (is_on_y_ident(p2)) return true;
std::cout << "XXXX p1: " << p1 << ", p2: " << p2 << std::endl;
auto cmp_xy = m_geom_traits->compare_xy_2_object();
return (cmp_xy(p2, p1) == SMALLER);
}
//! checks whether an point lies to the left of another point.
template <typename Arrangement, typename ZoneVisitor>
bool Arrangement_zone_2<Arrangement, ZoneVisitor>::
is_to_left_impl(const Point_2& p1, Arr_parameter_space ps1,
const Point_2& p2, Arr_parameter_space ps2,
Arr_boundary_cond_tag) const {
if (ps1 == ARR_LEFT_BOUNDARY) {
if (ps2 == ARR_LEFT_BOUNDARY) {
auto cmp_y_on_boundary = m_geom_traits->compare_y_on_boundary_2_object();
return (cmp_y_on_boundary(p2, p1) == SMALLER);
}
return false;
}
if (ps1 == ARR_RIGHT_BOUNDARY) {
if (ps2 == ARR_RIGHT_BOUNDARY) {
auto cmp_y_on_boundary = m_geom_traits->compare_y_on_boundary_2_object();
return (cmp_y_on_boundary(p2, p1) == SMALLER);
}
return true;
}
auto cmp_xy = m_geom_traits->compare_xy_2_object();
return (cmp_xy(p2, p1) == SMALLER);
}
//-----------------------------------------------------------------------------
// Compute the (lexicographically) leftmost intersection of the query
// curve with a given halfedge on the boundary of a face in the arrangement.
@ -866,11 +920,7 @@ _leftmost_intersection(Ccb_halfedge_circulator he_curr, bool on_boundary,
// Found a simple intersection point. Check if it is the leftmost
// intersection point so far.
if (! m_found_intersect ||
((intersection_location != ARR_RIGHT_BOUNDARY) &&
((leftmost_location == ARR_RIGHT_BOUNDARY) ||
compare_xy(ip, m_intersect_p) == SMALLER)))
{
if (! m_found_intersect || is_to_left(m_intersect_p, leftmost_location, ip, intersection_location)) {
// Store the leftmost intersection point and the halfedge handle.
m_intersect_p = ip;
m_ip_multiplicity = int_p->second;
@ -1034,9 +1084,14 @@ _zone_in_face(Face_handle face, bool on_boundary) {
// Set m_cv to be the remaining portion.
m_has_left_pt = true;
m_left_on_boundary = false;
m_left_pt = m_intersect_p;
m_cv = m_sub_cv2;
auto ps_in_x = m_geom_traits->parameter_space_in_x_2_object();
auto ps_in_y = m_geom_traits->parameter_space_in_y_2_object();
auto ps_x = ps_in_x(m_left_pt);
auto ps_y = ps_in_y(m_left_pt);
m_left_on_boundary = (ps_x != ARR_INTERIOR || ps_y != ARR_INTERIOR);
}
const X_monotone_curve_2* p_orig_curve = nullptr;

18
Arrangement_on_surface_2/include/CGAL/Arrangement_zone_2.h
View File

@ -415,6 +415,24 @@ private:
Arr_parameter_space& intersection_location,
Arr_boundary_cond_tag) const;
/*! checks whether an point lies to the left of another point.
*/
bool is_to_left(const Point_2& p1, Arr_parameter_space ps1,
const Point_2& p2, Arr_parameter_space ps2) const
{ return is_to_left_impl(p1, ps1, p2, ps2, Left_or_right_sides_category()); }
bool is_to_left_impl(const Point_2& p1, Arr_parameter_space ps1,
const Point_2& p2, Arr_parameter_space ps2,
Arr_all_sides_oblivious_tag) const;
bool is_to_left_impl(const Point_2& p1, Arr_parameter_space ps1,
const Point_2& p2, Arr_parameter_space ps2,
Arr_has_identified_side_tag) const;
bool is_to_left_impl(const Point_2& p1, Arr_parameter_space ps1,
const Point_2& p2, Arr_parameter_space ps2,
Arr_boundary_cond_tag) const;
/*! computes the (lexicographically) leftmost intersection of the query
* curve with a given halfedge on the boundary of a face in the arrangement.
*/