Differences From Artifact [bec880bc3280bac9]:
- File
lib/geo/ccw.cpp
- 2014-10-04 14:48:03 - part of checkin [ba015e9217] on branch trunk - 634 (user: kinaba) [annotate]
To Artifact [d88a2122970afda1]:
- File
lib/geo/ccw.cpp
- 2016-06-15 13:50:54 - part of checkin [cb4efc4fe0] on branch trunk - ccw (user: kinaba) [annotate]
18 18 }
19 19
20 20
21 21 // intersection of two line segments.
22 22 bool cross(CMP p1, CMP p2, CMP P1, CMP P2) {
23 23 return ccw(p1,p2,P1)*ccw(p1,p2,P2)<=0 && ccw(P1,P2,p1)*ccw(P1,P2,p2)<=0;
24 24 }
25 +
26 +
27 +// Intersection of two line segments, by p1+(*pos)(p2-p1) where 0<=*pos<=1.
28 +// only tested by local simple unittest. be careful.
29 +template<typename T>
30 +bool cross(const std::complex<T>& p1, const std::complex<T>& p2,
31 + const std::complex<T>& P1, const std::complex<T>& P2, T* pos) {
32 + if( ccw(p1,p2,P1)*ccw(p1,p2,P2)<=0 && ccw(P1,P2,p1)*ccw(P1,P2,p2)<=0 ) {
33 + if(outer_prod(p2-p1, P2-P1) == 0)
34 + return false; // parallel
35 + *pos = outer_prod(P1-p1, P2-P1) / outer_prod(p2-p1, P2-P1);
36 + return true;
37 + }
38 + return false;
39 +}