// ARC
void Intersect::visit(Arc_CSPtr arc, const geo::Vector& line) {
const geo::Coordinate nearest = line.nearestPointOnPath(arc->center());
double dist = arc->center().distanceTo(nearest);
// special case: arc touches line (tangent):
// TODO: We properly should add a tolorance here ??
if (fabs(dist - arc->radius()) < _tolerance) {
_intersectionPoints.push_back(nearest);
return;
}
const geo::Coordinate d = line.end() - line.start();
const double r = arc->radius();
const geo:: Coordinate delta = line.start() - arc->center();
const double d2 = d.squared();
//intersection
// solution = p + t d;
//| p -c+ t d|^2 = r^2
// |d|^2 t^2 + 2 (p-c).d t + |p-c|^2 -r^2 = 0
const double a1 = delta.dot(d);
const double discriminant = a1 * a1 - d2 * (delta.squared() - r * r);
if (discriminant < - _tolerance) {
return;
} else {
const double t = sqrtf(fabs(discriminant));
//two intersections
const geo::Coordinate c1(line.start() + d * (t - a1) / d2);
const geo::Coordinate c2(line.start() - d * (t + a1) / d2);
if (_method == Method::Any || (_method == Method::OnPath && arc->isCoordinateOnPath(c1) && line.isCoordinateOnPath(c1))) {
_intersectionPoints.push_back(c1);
}
if (_method == Method::Any || (_method == Method::OnPath && arc->isCoordinateOnPath(c2) && line.isCoordinateOnPath(c2))) {
_intersectionPoints.push_back(c2);
}
}
}
Arc::Arc(const Arc_CSPtr other, bool sameID) : CADEntity(other->layer(), other->metaTypes()), geo::Arc(other->center(), other->radius(), other->startAngle(), other->endAngle()) {
if (sameID) {
this->setID(other->id());
}
}
