/**
* Find intersections between two hyperbolas
*
* @param a Hyperbola
* @param b Hyperbola
* @param iPts where to store intersection points; null to construct
*/
public static DArray findIntersections(Hyperbola a, Hyperbola b, DArray iPts) {
final boolean db = false;
if (iPts == null) iPts = new DArray();
iPts.clear();
final DArray jPts = new DArray();
// a.initClipIfNec();
// b.initClipIfNec();
if (db) {
System.out.println(
"finding intersections between:\n" + a.toString(true) + "\n" + b.toString(true));
}
PlaneCurve.findIntersect(a.getCurve(), b.getCurve(), jPts);
// filter out false intersections
if (db) {
System.out.println("prefilter # intersections= " + jPts.size());
}
FPoint2 ptc = new FPoint2();
for (int i = 0; i < jPts.size(); i++) {
FPoint2 pt = jPts.getFPoint2(i);
// make sure calculated intersect point is actually on both arms
{
FPoint2 data = a.calcParameterAndDistance(pt);
if (data.y > .001) continue;
data = b.calcParameterAndDistance(pt);
if (data.y > .001) continue;
}
if (!a.isLine()) {
// put in curve space to verify it's to the right of the y axis
a.toCurveSpace(pt, ptc);
if (db) {
System.out.println("Filter " + i + " in curveA= " + ptc);
}
if (ptc.x <= 0) {
if (db) {
System.out.println(" < 0");
}
continue;
}
}
if (!b.isLine()) {
b.toCurveSpace(pt, ptc);
if (db) {
System.out.println(" in curveB= " + ptc);
}
if (ptc.x <= 0) {
if (db) {
System.out.println(" < 0");
}
continue;
}
}
if (db) {
System.out.println(" adding " + pt);
}
iPts.add(pt);
}
return iPts;
}
