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cviumcvium
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dcel, beginning of naive emst, half way done with convex dt
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9 files changed

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‎.idea/workspace.xml

Lines changed: 403 additions & 240 deletions
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‎src/main/java/convex_dt/ConvexDT.java

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package convex_dt;
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import dcel.HalfEdge;
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import kds.KDSPoint;
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import static convex_dt.Utils.*; // not very nice, but it's to avoid having to write Utils.<func> everywhere
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import static convex_dt.ConvexShape.*;
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import sun.reflect.generics.reflectiveObjects.NotImplementedException;
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import java.util.ArrayList;
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/**
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* Created by cvium on 29-11-2016.
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*/
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public class ConvexDT {
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private HalfEdge base;
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private HalfEdge lcand;
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private HalfEdge rcand;
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private ConvexShape shape;
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private ArrayList<KDSPoint> points;
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public ConvexDT() {
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}
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public ConvexDT(ArrayList<KDSPoint> points, ConvexShape shape) {
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throw new NotImplementedException();
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}
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public HalfEdge computeSmallDelaunay(ArrayList<KDSPoint> points) {
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throw new NotImplementedException();
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}
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public HalfEdge findLowerSupport(HalfEdge left, HalfEdge right) {
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if (lowerThan(left.getOrigin(), right.getOrigin())) {
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while (shape.inInfCircle(rNext(right).getOrigin(), left.getOrigin(), right.getOrigin()) ==
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infCircleEnum.INSIDE && lessThan(rNext(right).getOrigin(), right.getOrigin())) {
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right = rNext(right);
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}
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if (shape.inInfCircle(right.getDestination(), left.getOrigin(), right.getOrigin()) == infCircleEnum.INSIDE) {
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right = rPrev(right);
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} else if (shape.inInfCircle(left.getDestination(), left.getOrigin(), right.getOrigin()) == infCircleEnum.INSIDE) {
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left = rPrev(left);
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} else {
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return connect(right.getTwin(), oPrev(left));
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}
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} else {
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// TODO ????
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throw new NotImplementedException();
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}
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// TODO ??????
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return connect(right, left);
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}
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public void makeBundle(HalfEdge edge) {
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if (edge != lNext(lNext(lNext(edge)))) {
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if (lNext(edge).isBridge()) delete(lNext(edge));
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if (dNext(edge).isBridge()) delete(dNext(edge));
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connect(edge, lPrev(edge)).markBridge();
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}
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}
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public HalfEdge unBundle(HalfEdge edge) {
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HalfEdge fixed, moving, returnEdge, junk;
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if (onLine(oNext(edge).getDestination(), edge.getOrigin(), edge.getDestination())) {
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fixed = oPrev(edge);
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moving = lNext(lNext(edge));
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returnEdge = oNext(edge);
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} else {
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fixed = lNext(edge);
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moving = lNext(oPrev(edge));
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returnEdge = oPrev(edge);
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}
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while (fixed != moving) {
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junk = connect(fixed, moving);
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moving = lNext(moving);
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}
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return returnEdge;
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}
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public void unBundleAll(HalfEdge edge) {
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HalfEdge current;
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for (int direction = 1; direction <= 2; ++direction) {
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current = oNext(edge);
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while (current != edge) {
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if (current.isBridge()) current = unBundle(current);
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else current = oNext(current);
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}
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edge = edge.getTwin();
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}
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}
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public HalfEdge produceONext(HalfEdge edge) {
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if (lNext(edge).isBridge()) {
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delete(lNext(edge));
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makeBundle(connect(lNext(edge), edge).getTwin());
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} else if (oNext(edge).isBridge()) {
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delete(oNext(edge));
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makeBundle(oPrev(connect(edge, lPrev(edge))));
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}
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return oNext(edge);
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}
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public HalfEdge produceOPrev(HalfEdge edge) {
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if (lPrev(edge).isBridge()) {
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delete(lPrev(edge));
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makeBundle(connect(lPrev(edge), edge).getTwin());
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} else if (oPrev(edge).isBridge()) {
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delete(oPrev(edge));
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makeBundle(oNext(connect(edge, lNext(edge))));
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}
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return oPrev(edge);
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}
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public HalfEdge connect(HalfEdge a, HalfEdge b) {
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// TODO: does this work?
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HalfEdge newEdge = new HalfEdge(a.getDestination(), b.getOrigin());
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a.setNext(newEdge);
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b.setPrev(newEdge);
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// hackish way to create the twin
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newEdge.getTwin();
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return newEdge;
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}
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public void delete(HalfEdge e) {
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// remove e from its prev and next edges, TODO: IS THAT ENOUGH?
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e.getPrev().setNext(null);
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e.getNext().setPrev(null);
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// have to remove the twin as well
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e.getTwin().getPrev().setNext(null);
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e.getTwin().getNext().setPrev(null);
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}
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public HalfEdge connectLeft() {
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unBundleAll(lcand);
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// \__ Base is directed from right to left, so base dest must be connected to lcand's origin
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return connect(base.getTwin(), lcand.getTwin());
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}
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public HalfEdge connectRight() {
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unBundleAll(rcand);
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// TODO: should this be reversed? THINK NOT
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// __/ Base is directed from left to right, so base dest must be connected to rcand's origin
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return connect(base.getTwin(), rcand.getTwin());
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}
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public HalfEdge computeLcand() {
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HalfEdge current = null, top = null, t = null;
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lcand = rPrev(base);
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if (shape.inInfCircle(lcand.getDestination(), base.getOrigin(), base.getDestination()) == infCircleEnum.BEFORE) {
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lcand = produceONext(lcand);
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while (shape.inInfCircle(lcand.getDestination(), base.getOrigin(), base.getDestination()) == infCircleEnum.BEFORE) {
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delete(oPrev(lcand));
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lcand = produceONext(lcand);
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}
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if (isValid(lcand)) delete(oPrev(lcand));
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else lcand = oPrev(lcand);
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}
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if (isValid(lcand)) {
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current = oNext(lcand);
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top = lcand;
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switch(shape.inCircle(lcand.getOrigin(), lcand.getDestination(), base.getOrigin(), current.getDestination())) {
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case INSIDE:
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if (current.isBridge() || rPrev(current).isBridge()) {
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current = produceONext(oPrev(current));
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}
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if (leftOf(current.getDestination(), lcand.getOrigin(), lcand.getDestination())) {
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if (rPrev(current) != dPrev(lcand))
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makeBundle(connect(lcand, current.getTwin()).getTwin());
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if (current != oNext(lcand))
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makeBundle(lNext(connect(lPrev(lcand), current.getTwin())));
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t = produceONext(lcand);
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delete(lcand);
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lcand = t;
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current = oNext(lcand);
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top = lcand;
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} else {
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// We have lcand
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break;
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//return lcand;
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}
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break;
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case ONBEFORE:
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if (leftOf(current.getDestination(), current.getOrigin(), lcand.getDestination())) {
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current = rPrev(current);
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} else{
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return lcand;
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}
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break;
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case ONAFTER:
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top = dNext(top);
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t = current;
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current = oNext(current);
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delete(current);
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break;
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default:
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//return lcand;
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break;
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}
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} else {
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System.out.println("lcand not valid???");
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}
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// TODO top shouldn't be null I think
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//assert top != null;
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//assert current != null;
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if (top != lcand) {
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makeBundle(lNext(connect(top, lcand)));
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top = oNext(lcand);
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}
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if (oPrev(current) != top) {
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makeBundle(oPrev(connect(top, oPrev(current))));
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}
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return lcand;
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}
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public HalfEdge computeRcand() {
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HalfEdge current = null, top = null, t = null;
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// TODO ?
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HalfEdge base_twin = base.getTwin();
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rcand = lNext(base_twin);
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if (shape.inInfCircle(rcand.getDestination(), base_twin.getOrigin(), base_twin.getDestination()) == infCircleEnum.BEFORE) {
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rcand = produceOPrev(rcand);
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while (shape.inInfCircle(rcand.getDestination(), base_twin.getOrigin(), base_twin.getDestination()) == infCircleEnum.BEFORE) {
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delete(oNext(rcand));
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rcand = produceOPrev(rcand);
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}
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if (isValid(rcand)) delete(oNext(rcand));
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else rcand = oNext(rcand);
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}
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if (isValid(rcand)) {
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current = oPrev(rcand);
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top = rcand;
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switch(shape.inCircle(rcand.getOrigin(), rcand.getDestination(), base_twin.getOrigin(), current.getDestination())) {
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case INSIDE:
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if (current.isBridge() || lNext(current).isBridge()) {
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current = produceOPrev(lNext(current));
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}
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if (leftOf(current.getDestination(), rcand.getOrigin(), rcand.getDestination())) {
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if (lNext(current) != rcand) {
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}
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}
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break;
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case ONBEFORE:
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break;
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case ONAFTER:
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break;
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default:
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// we have rcand
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break;
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}
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}
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throw new NotImplementedException();
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}
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public HalfEdge delaunay(ArrayList<KDSPoint> points) {
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if (points.size() < 4) return computeSmallDelaunay(points);
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else {
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int split = (int) Math.floor(points.size() / 2);
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ArrayList<KDSPoint>left = (ArrayList<KDSPoint>) points.subList(0, split);
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ArrayList<KDSPoint> right = (ArrayList<KDSPoint>) points.subList(split + 1, points.size());
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HalfEdge lleft = delaunay(left);
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HalfEdge lright = delaunay(right);
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base = findLowerSupport(lleft, lright);
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boolean leftLower = lowerThan(lleft.getOrigin(), lright.getOrigin());
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HalfEdge lower;
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if (leftLower) {
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if (lleft.getOrigin() == base.getDestination()) lower = base.getTwin();
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else lower = lleft;
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} else {
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lower = rNext(lright);
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}
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lcand = computeLcand();
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rcand = computeRcand();
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if (isValid(lcand) && isValid(rcand)) {
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switch(shape.inCircle(base.getOrigin(), base.getDestination(), lcand.getDestination(), rcand.getDestination())) {
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case INSIDE:
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base = connectRight();
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break;
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case ON:
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case ONBEFORE:
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case ONAFTER:
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if (rightOf(rcand.getDestination(), lcand.getOrigin(), lcand.getDestination())) {
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base = connectRight();
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} else {
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base = connectLeft();
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}
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break;
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default:
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base = connectLeft();
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}
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}
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else if (isValid(lcand)) base = connectLeft();
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else if (isValid(rcand)) base = connectRight();
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else if (shape.inInfCircle(rcand.getDestination(), base.getOrigin(), base.getDestination()) == infCircleEnum.AFTER) {
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while (shape.inInfCircle(lcand.getDestination(), lcand.getOrigin(), rcand.getDestination()) == infCircleEnum.INSIDE) {
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lcand = rPrev(lcand);
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}
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base = connect(rcand, oPrev(lcand));
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delete(rcand);
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}
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else if (shape.inInfCircle(rcand.getDestination(), base.getOrigin(), base.getDestination()) == infCircleEnum.AFTER) {
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while (shape.inInfCircle(rcand.getDestination(), lcand.getDestination(), rcand.getOrigin()) == infCircleEnum.INSIDE) {
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rcand = lNext(rcand);
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}
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base = connect(lPrev(rcand), lcand.getTwin());
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delete(lcand);
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}
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if (!leftLower) lower = rPrev(lower);
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return lower;
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}
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}
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public boolean isValid(HalfEdge e) {
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return shape.inInfCircle(e.getDestination(), base.getOrigin(), base.getDestination()) == infCircleEnum.INSIDE;
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}
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}

‎src/main/java/convex_dt/ConvexShape.java

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package convex_dt;
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import kds.KDSPoint;
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/**
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* Created by cvium on 03-12-2016.
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*/
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public interface ConvexShape {
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circleEnum inCircle(KDSPoint a, KDSPoint b, KDSPoint c, KDSPoint d);
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/**
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* Predicate test to determine where point a lies wrt. to the infinite circle with b and c on the boundary.
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*
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* @param a The query point
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* @param b First point on the boundary of the infinite circle
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* @param c The second point on the boundary of the infinite circle
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* @return inside, outside, before, after
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*/
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infCircleEnum inInfCircle(KDSPoint a, KDSPoint b, KDSPoint c);
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enum infCircleEnum {
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INSIDE, OUTSIDE, BEFORE, AFTER
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}
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enum circleEnum {
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INSIDE, OUTSIDE, ONBEFORE, ONAFTER, ON
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}
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}

‎src/main/java/convex_dt/Pie.java

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package convex_dt;
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import kds.KDSPoint;
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/**
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* Created by cvium on 03-12-2016.
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*/
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public class Pie implements ConvexShape {
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public Pie() {
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}
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@Override
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public circleEnum inCircle(KDSPoint a, KDSPoint b, KDSPoint c, KDSPoint d) {
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return null;
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}
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@Override
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public infCircleEnum inInfCircle(KDSPoint a, KDSPoint b, KDSPoint c) {
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return null;
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}
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}

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