public IEnumerable <Point2D> Range(RectHV rect)
{
var queue = new Queue <Point2D>();
Range(root, Container, rect, queue);
return(queue);
}
private static RectHV RightRect(RectHV rect, KdNode node)
{
if (node.Vertical)
{
return(new RectHV(node.X, rect.Ymin, rect.Xmax, rect.Ymax));
}
return(new RectHV(rect.Xmin, node.Y, rect.Xmax, rect.Ymax));
}
private Point2D Nearest(KdNode node, RectHV rect, double x, double y, Point2D candidate)
{
if (node == null)
{
return(candidate);
}
double dqn = 0;
double drq = 0;
var query = new Point2D(x, y);
var nearest = candidate;
if (nearest != null)
{
dqn = query.DistanceSquaredTo(nearest);
drq = rect.DistanceSquaredTo(query);
}
if (nearest == null || dqn < drq)
{
var point = new Point2D(node.X, node.Y);
if (nearest == null || dqn > query.DistanceSquaredTo(point))
{
nearest = point;
}
}
var left = LeftRect(rect, node);
var right = RightRect(rect, node);
if (node.Vertical)
{
if (x < node.X)
{
nearest = Nearest(node.Left, left, x, y, nearest);
nearest = Nearest(node.Right, right, x, y, nearest);
}
else
{
nearest = Nearest(node.Right, right, x, y, nearest);
nearest = Nearest(node.Left, left, x, y, nearest);
}
}
else
{
if (y < node.Y)
{
nearest = Nearest(node.Left, left, x, y, nearest);
nearest = Nearest(node.Right, right, x, y, nearest);
}
else
{
nearest = Nearest(node.Right, right, x, y, nearest);
nearest = Nearest(node.Left, left, x, y, nearest);
}
}
return(nearest);
}
private void Range(KdNode node, RectHV nrect, RectHV rect, Queue<Point2D> queue) {
if (node == null) {
return;
}
if (rect.Intersects(nrect)) {
var p = new Point2D(node.X, node.Y);
if (rect.Contains(p)) {
queue.Enqueue(p);
}
Range(node.Left, LeftRect(nrect, node), rect, queue);
Range(node.Right, RightRect(nrect, node), rect, queue);
}
}
private void Range(KdNode node, RectHV nrect, RectHV rect, Queue <Point2D> queue)
{
if (node == null)
{
return;
}
if (rect.Intersects(nrect))
{
var p = new Point2D(node.X, node.Y);
if (rect.Contains(p))
{
queue.Enqueue(p);
}
Range(node.Left, LeftRect(nrect, node), rect, queue);
Range(node.Right, RightRect(nrect, node), rect, queue);
}
}
public bool Intersects(RectHV that)
{
return(Xmax >= that.Xmin && Ymax >= that.Ymin &&
that.Xmax >= Xmin && that.Ymax >= Ymin);
}
private static RectHV RightRect(RectHV rect, KdNode node) {
if (node.Vertical) {
return new RectHV(node.X, rect.Ymin, rect.Xmax, rect.Ymax);
}
return new RectHV(rect.Xmin, node.Y, rect.Xmax, rect.Ymax);
}
public IEnumerable<Point2D> Range(RectHV rect) {
var queue = new Queue<Point2D>();
Range(root, Container, rect, queue);
return queue;
}
public bool Intersects(RectHV that) {
return Xmax >= that.Xmin && Ymax >= that.Ymin
&& that.Xmax >= Xmin && that.Ymax >= Ymin;
}
private Point2D Nearest(KdNode node, RectHV rect, double x, double y, Point2D candidate) {
if (node == null) {
return candidate;
}
double dqn = 0;
double drq = 0;
var query = new Point2D(x, y);
var nearest = candidate;
if (nearest != null) {
dqn = query.DistanceSquaredTo(nearest);
drq = rect.DistanceSquaredTo(query);
}
if (nearest == null || dqn < drq) {
var point = new Point2D(node.X, node.Y);
if (nearest == null || dqn > query.DistanceSquaredTo(point)) {
nearest = point;
}
}
var left = LeftRect(rect, node);
var right = RightRect(rect, node);
if (node.Vertical) {
if (x < node.X) {
nearest = Nearest(node.Left, left, x, y, nearest);
nearest = Nearest(node.Right, right, x, y, nearest);
}
else {
nearest = Nearest(node.Right, right, x, y, nearest);
nearest = Nearest(node.Left, left, x, y, nearest);
}
}
else {
if (y < node.Y) {
nearest = Nearest(node.Left, left, x, y, nearest);
nearest = Nearest(node.Right, right, x, y, nearest);
}
else {
nearest = Nearest(node.Right, right, x, y, nearest);
nearest = Nearest(node.Left, left, x, y, nearest);
}
}
return nearest;
}
