/**
* Calculate parameter for a point, and indicate how close the point is to the curve
*
* @param pt : point to find parameter for
* @return FPoint2; x contains the parameter, y is its distance from the curve
*/
private FPoint2 calcParameterAndDistance(FPoint2 pt) {
final FPoint2 ept = new FPoint2();
toCurveSpace(pt, ept);
double t = toExt(ept.y);
FPoint2 as = calcPointInArmSpace(t);
return new FPoint2(t, Math.abs(ept.x - as.x));
}
/**
* Determine where point is relative to arm
*
* @param x :
* @param y : point to test
* @return an integer, which is 0 if it's on the arm, 1 if it's to the right of the arm, -1 if
* it's to the left of the arm
*/
public int testPoint(double x, double y) {
final FPoint2 ept = new FPoint2(), eps = new FPoint2();
eps.setLocation(x, y);
toCurveSpace(eps, ept);
FPoint2 as = calcPointInArmSpace(toExt(ept.y));
int out = 0;
double diff = ept.x - as.x;
if (diff > 0) {
out = 1;
} else if (diff < 0) {
out = -1;
}
if (flipped()) {
out = -out;
}
return out;
}
/**
* Calculate the parameter associated with a point
*
* @param pt : point to find parameter for
* @return best-fit parameter for this point
*/
public double calcParameter(FPoint2 pt) {
final FPoint2 ept = new FPoint2();
toCurveSpace(pt, ept);
return toExt(ept.y);
}
/**
* 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;
}
