/*-
* Copyright 2020 Beuth Hochschule für Technik Berlin, Hochschule für Technik Stuttgart
*
* This file is part of CityDoctor2.
*
* CityDoctor2 is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* CityDoctor2 is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with CityDoctor2. If not, see .
*/
package de.hft.stuttgart.citydoctor2.edge;
import java.util.List;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
public class HalfEdge extends BaseEntity {
private static final Logger logger = LogManager.getLogger(HalfEdge.class);
private static final boolean ALLOW_CIRCULAR_CHAINS = false;
private Coordinate3d start;
private Coordinate3d end;
private HalfEdge partner;
private HalfEdge next;
public HalfEdge(Coordinate3d start, Coordinate3d end, EdgePolygon parent) {
this.start = start;
this.end = end;
List halfEdgesToStart = start.getParents(HalfEdge.class);
List halfEdgesToEnd = end.getParents(HalfEdge.class);
HalfEdge tempPartner;
if (parent == null) {
tempPartner = findPartner(halfEdgesToStart, halfEdgesToEnd);
} else {
tempPartner = findPartner(parent, halfEdgesToStart, halfEdgesToEnd);
}
if (tempPartner != null) {
setPartner(tempPartner);
}
addChild(start);
addChild(end);
}
public HalfEdge(Coordinate3d start, Coordinate3d end) {
this(start, end, null);
}
private HalfEdge findPartner(EdgePolygon parent, List halfEdgesToStart, List halfEdgesToEnd) {
HalfEdge tempPartner = null;
for (HalfEdge heStart : halfEdgesToStart) {
for (HalfEdge heEnd : halfEdgesToEnd) {
if (heStart == heEnd) {
tempPartner = heStart;
if (tempPartner.getPartner() == null) {
EdgePolygon partnerParent = tempPartner.getPolygon();
if (partnerParent != null || partnerParent != parent) {
return tempPartner;
}
}
}
}
}
return tempPartner;
}
private HalfEdge findPartner(List halfEdgesToStart, List halfEdgesToEnd) {
HalfEdge tempPartner = null;
for (HalfEdge heStart : halfEdgesToStart) {
for (HalfEdge heEnd : halfEdgesToEnd) {
if (heStart == heEnd) {
tempPartner = heStart;
if (tempPartner.getPartner() == null) {
EdgePolygon partnerParent = tempPartner.getPolygon();
if (partnerParent != null) {
return tempPartner;
}
}
}
}
}
return tempPartner;
}
public void setPartner(HalfEdge partner) {
if (partner == this) {
logger.debug("HalfEdge.setPartner() : cannot reference myself");
return;
}
if (null != this.partner) {
if (null != partner) {
if (ALLOW_CIRCULAR_CHAINS) {
// check if the the partner already exists in the list of partners
HalfEdge pNextPartner = this.partner;
while (pNextPartner != this) {
if (pNextPartner == partner) {
logger.debug("(HalfEdge " + partner + " already exits in chain");
return;
}
pNextPartner = pNextPartner.partner;
}
// insert new partner in list
partner.partner = this.partner;
this.partner = partner;
} else {
logger.debug("Cannot overwrite existing partner-connection, set the connection to null first!");
}
} else {
// remove the existing connection
this.partner.partner = null;
this.partner = null;
}
} else {
if (partner != null) {
if (partner.partner != null) {
if (ALLOW_CIRCULAR_CHAINS) {
// this partner pointer is NULL and pPartner->mpPartner is not
// NULL ==> insert this half edge in the chain of pPartner
// first get the predecessor half edge of pPartner
HalfEdge pNextPartner = partner.partner;
HalfEdge pPreviousPartner = partner;
while (pNextPartner != partner) {
pPreviousPartner = pNextPartner;
pNextPartner = pNextPartner.partner;
}
// insert new partner in list
pPreviousPartner.partner = this;
this.partner = partner;
} else {
/**
* TODO : das riecht nach einer Ringverzeigerung : 3 Polygonraender treffen auf
* einander
*/
logger.debug("Cannot overwrite existing partner-connection, set the connection to null first!");
}
} else {
this.partner = partner;
partner.partner = this;
}
}
}
}
public HalfEdge getPartner() {
return partner;
}
public EdgePolygon getPolygon() {
List polygons = getParents(EdgePolygon.class);
if (!polygons.isEmpty()) {
return polygons.get(0);
}
return null;
}
public GmBoundedStraight getStraight() {
return GmBoundedStraight.of(start.getPoint(), end.getPoint());
}
public Coordinate3d getStart() {
return start;
}
public Coordinate3d getEnd() {
return end;
}
public HalfEdge getNext() {
return next;
}
public void setNext(HalfEdge next) {
this.next = next;
}
@Override
public String toString() {
return "HalfEdge [start=" + start + ", end=" + end + "]";
}
}