bool
PolygonInterior(const FlatGeoPoint &P,
SearchPointVector::const_iterator begin,
SearchPointVector::const_iterator end)
{
if (std::distance(begin, end) < 3)
return false;
int wn = 0; // the winding number counter
// loop through all edges of the polygon
for (auto i = begin, next = std::next(i); next != end;
i = next, next = std::next(i)) {
// edge from current to next
if (i->GetFlatLocation().y <= P.y) {
// start y <= P.y
if (next->GetFlatLocation().y > P.y)
// an upward crossing
if (isLeft(i->GetFlatLocation(), next->GetFlatLocation(), P) > 0)
// P left of edge
// have a valid up intersect
++wn;
} else {
// start y > P.y (no test needed)
if (next->GetFlatLocation().y <= P.y)
// a downward crossing
if (isLeft(i->GetFlatLocation(), next->GetFlatLocation(), P) < 0)
// P right of edge
// have a valid down intersect
--wn;
}
}
return wn != 0;
}
bool
SearchPointVector::IntersectsWith(const FlatRay &ray) const
{
for (auto it = begin(); it + 1 != end(); ++it) {
const FlatRay r_seg(it->GetFlatLocation(), (it + 1)->GetFlatLocation());
if (r_seg.IntersectsDistinct(ray))
return true;
}
return false;
}
SearchPointVector::const_iterator
SearchPointVector::NearestIndexConvex(const FlatGeoPoint &p3) const
{
unsigned distance_min = 0 - 1;
const_iterator i_best = end();
// find nearest point in vector
for (auto i = begin(); i != end(); ++i) {
unsigned d_this = p3.DistanceSquared(i->GetFlatLocation());
if (d_this < distance_min) {
distance_min = d_this;
i_best = i;
}
}
return i_best;
}
AirspaceIntersectionVector
AirspacePolygon::Intersects(const GeoPoint &start, const GeoPoint &end,
const TaskProjection &projection) const
{
const FlatRay ray(projection.ProjectInteger(start),
projection.ProjectInteger(end));
AirspaceIntersectSort sorter(start, *this);
for (auto it = m_border.begin(); it + 1 != m_border.end(); ++it) {
const FlatRay r_seg(it->GetFlatLocation(), (it + 1)->GetFlatLocation());
fixed t = ray.DistinctIntersection(r_seg);
if (!negative(t))
sorter.add(t, projection.Unproject(ray.Parametric(t)));
}
return sorter.all();
}
