/**
* Calc possible hull from a set of polygons
*
* @param polySet set of polygons
* @param first first polygon to include
* @param last last polygon to include
* @return polygon containing possible hull
*/
private static EdPolygon calcPHullRange(EdPolygon[] polySet, int first, int last) {
final boolean db = true;
int len = last + 1 - first;
if (len == 1) return polySet[first];
if (len > 2) {
if (db && T.update()) {
DArray a = new DArray();
for (int i = first; i <= last; i++) a.add(polySet[i]);
T.msg("calc possible hull of multiple polygons" + T.show(a, MyColor.cRED, STRK_THICK, -1));
}
int n = len / 2;
return calcPHull(
calcPHullRange(polySet, first, first + n - 1), calcPHullRange(polySet, first + n, last));
}
return calcPHull(polySet[first], polySet[first + 1]);
}
private static void OLDexpandHull(
PtEntry convHullEntry, PtEntry aHull, PtEntry bHull, boolean ccw) {
boolean db__OLD = C.vb(DB_HULLEXPAND);
if (db__OLD && T.update()) T.msg("expandHull" + T.show(convHullEntry) + " ccw=" + ccw);
PtEntry[] opp = new PtEntry[2];
opp[0] = aHull;
opp[1] = bHull;
PtEntry old____hEnt = convHullEntry;
boolean advanced = false;
do {
if (old____hEnt != convHullEntry) advanced = true;
inf.update();
if (old____hEnt.source() == null) {
if (db__OLD && T.update())
T.msg("expandHull, source unknown, guaranteed not convex" + T.show(old____hEnt));
old____hEnt = old____hEnt.next(ccw);
continue;
}
int w = (old____hEnt.source() == opp[0].source()) ? 1 : 0;
PtEntry oppEnt = opp[w];
boolean isTangent =
!COper3.right(old____hEnt, oppEnt, oppEnt.next(true), ccw)
&& !COper3.right(old____hEnt, oppEnt, oppEnt.prev(true), ccw);
if (!isTangent) {
if (db__OLD && T.update())
T.msg(
"expandHull, advance tangent line"
+ T.show(oppEnt.toPolygon(), MyColor.cDARKGRAY, -1, MARK_X)
+ T.show(old____hEnt)
+ tl(old____hEnt, oppEnt));
opp[w] = oppEnt.next(ccw);
continue;
}
if (COper3.left(old____hEnt, oppEnt, old____hEnt.next(ccw), ccw)
&& COper3.left(old____hEnt, oppEnt, old____hEnt.prev(ccw), ccw)) {
DArray dispPts = new DArray();
// delete points until cross tangent line
PtEntry next = old____hEnt.next(ccw);
while (true) {
PtEntry prev = next;
dispPts.add(prev);
next = prev.delete(ccw);
inf.update();
if (COper3.right(old____hEnt, oppEnt, next, ccw)) {
FPoint2 cross = MyMath.linesIntersection(old____hEnt, oppEnt, prev, next, null);
old____hEnt = old____hEnt.insert(new PtEntry(cross), ccw);
if (db__OLD && T.update())
T.msg(
"expandHull, clipped to shadow region"
+ tl(old____hEnt, oppEnt)
+ T.show(old____hEnt)
+ T.show(dispPts));
break;
}
}
} else {
if (db__OLD && T.update())
T.msg(
"expandHull, not dipping into shadow region"
+ T.show(old____hEnt.next(ccw))
+ tl(old____hEnt, oppEnt));
}
old____hEnt = old____hEnt.next(ccw);
} while (!advanced || old____hEnt != convHullEntry);
}
/**
* Apply hull expansion procedure
*
* @param convHullEntry an entry of the hull (should be on the convex hull, so it is not deleted
* or replaced and is still valid for subsequent calls)
* @param aHull entry on convex hull of polygon A
* @param bHull entry on convex hull of polygon B
* @param ccw true to move in ccw direction, else cw
*/
private static void expandHull(PtEntry convHullEntry, PtEntry aHull, PtEntry bHull, boolean ccw) {
if (C.vb(OLDMETHOD)) {
OLDexpandHull(convHullEntry, aHull, bHull, ccw);
return;
}
boolean db = C.vb(DB_HULLEXPAND);
if (db && T.update()) T.msg("expandHull" + T.show(convHullEntry) + " ccw=" + ccw);
// tangent points for A, B
PtEntry[] tangentPoints = new PtEntry[2];
tangentPoints[0] = aHull;
tangentPoints[1] = bHull;
PtEntry hEnt = convHullEntry;
do {
inf.update();
// calculate tangent ray R
PtEntry tangentPt = null;
while (true) {
int tanIndex = (hEnt.source() == tangentPoints[0].source()) ? 1 : 0;
tangentPt = tangentPoints[tanIndex];
if (!COper3.right(hEnt, tangentPt, tangentPt.next(true), ccw)
&& !COper3.right(hEnt, tangentPt, tangentPt.prev(true), ccw)) break;
tangentPt = tangentPt.next(ccw);
if (db && T.update())
T.msg(
"expandHull, advance tangent line"
+ T.show(tangentPt.toPolygon(), MyColor.cDARKGRAY, -1, MARK_DISC)
+ T.show(hEnt)
+ tl(hEnt, tangentPt));
tangentPoints[tanIndex] = tangentPt;
}
if (COper3.left(hEnt, tangentPt, hEnt.next(ccw), ccw)) {
DArray dispPts = new DArray();
// delete points until cross tangent line
PtEntry next = hEnt.next(ccw);
while (true) {
PtEntry prev = next;
dispPts.add(prev);
next = prev.delete(ccw);
if (COper3.right(hEnt, tangentPt, next, ccw)) {
FPoint2 cross = MyMath.linesIntersection(hEnt, tangentPt, prev, next, null);
hEnt = hEnt.insert(new PtEntry(cross), ccw);
if (db && T.update())
T.msg(
"expandHull, clipped to shadow region"
+ tl(hEnt, tangentPt)
+ T.show(hEnt)
+ T.show(dispPts));
break;
}
}
} else {
if (db && T.update())
T.msg(
"expandHull, not dipping into shadow region"
+ T.show(hEnt.next(ccw))
+ tl(hEnt, tangentPt));
}
while (true) {
hEnt = hEnt.next(ccw);
if (COper3.left(hEnt.prev(ccw), hEnt, hEnt.next(ccw), ccw)) break;
if (db && T.update()) T.msg("skipping reflex vertex" + T.show(hEnt));
}
} while (hEnt != convHullEntry);
}
