boost/geometry
2
0
Fork 0
mirror of https://github.com/boostorg/geometry.git synced 2026-02-09 23:22:10 +00:00
Code Issues Projects Releases Wiki Activity

Fixed robustness problem for case called "ggl_list_20110306_javier"

Browse Source 
[SVN r69611]
This commit is contained in:
Barend Gehrels
2011-03-06 21:15:21 +00:00
parent 1f69fc31bf
commit 394b7ec79d
1 changed files with 23 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
include/boost/geometry/strategies/cartesian/cart_intersect.hpp
View File

@@ -336,7 +336,29 @@ private :
// For case 5-8: b_1 < (a_1 or a_2) < b_2, two intersections are equal to segment A
if (has_common_points)
{
bool const a_in_b = (b_1 < a_1 && a_1 < b_2) || (b_1 < a_2 && a_2 < b_2);
// Either A is in B, or B is in A, or (in case of robustness/equals)
// both are true, see below
bool a_in_b = (b_1 < a_1 && a_1 < b_2) || (b_1 < a_2 && a_2 < b_2);
bool b_in_a = (a_1 < b_1 && b_1 < a_2) || (a_1 < b_2 && b_2 < a_2);
if (a_in_b && b_in_a)
{
// testcase "ggl_list_20110306_javier"
// In robustness it can occur that a point of A is inside B AND a point of B is inside A,
// still while has_common_points is true (so one point equals the other).
// If that is the case we select on length.
coordinate_type const length_a = abs(a_1 - a_2);
coordinate_type const length_b = abs(b_1 - b_2);
if (length_a > length_b)
{
a_in_b = false;
}
else
{
b_in_a = false;
}
}
int const arrival_a = a_in_b ? 1 : -1;
if (a2_eq_b2) return Policy::collinear_interior_boundary_intersect(a_in_b ? a : b, a_in_b, 0, 0, false);
if (a1_eq_b2) return Policy::collinear_interior_boundary_intersect(a_in_b ? a : b, a_in_b, arrival_a, 0, true);