/// Boolean intersection test.
int Line::Intersect(Line & withOtherLine)
{
// http://www.geeksforgeeks.org/check-if-two-given-line-segments-intersect/
int or1 = Orientation(start, stop, withOtherLine.start);
int or2 = Orientation(start, stop, withOtherLine.stop);
int or3 = Orientation(withOtherLine.start, withOtherLine.stop, start);
int or4 = Orientation(withOtherLine.start, withOtherLine.stop, stop);
// Ok, we got an intersection confirmed, now the question is what type.
if (or1 != or2 && or3 != or4)
return IntersectionType::GENERAL;
// Special Cases for colinearity, may be either be end-points occuring on the other line or complete colinearity.
bool colinear1 = false, colinear2 = false;
if (or1 == COLINEAR && PointOnSegment(start, stop, withOtherLine.start) ||
or2 == COLINEAR && PointOnSegment(start, stop, withOtherLine.stop))
{
colinear1 = true;
}
if (or3 == COLINEAR && PointOnSegment(withOtherLine.start, withOtherLine.stop, start) ||
or4 == COLINEAR && PointOnSegment(withOtherLine.start, withOtherLine.stop, stop))
{
colinear2 = true;
}
if (colinear1 && colinear2)
{
return IntersectionType::COLINEAR;
}
else if (colinear1 || colinear2)
return IntersectionType::POINT_IN_SEGMENT;
return IntersectionType::NO_INTERSECTION;
}
int OnCHEdge(int u)
{
int i;
for (i=0;i<chnum;i++) if (PointOnSegment(p[u],p[res[i]],p[res[(i+1)%chnum]])) break;
return i;
}