/*-
* 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.math;
import java.util.ArrayList;
import java.util.List;
import de.hft.stuttgart.citydoctor2.datastructure.LinearRing;
import de.hft.stuttgart.citydoctor2.datastructure.Vertex;
/**
* A ring moved by an offset. Used to avoid numerical inaccuracies
*
* @author Matthias Betz
*
*/
public class MovedRing {
private List vertices;
private LinearRing original;
public static MovedRing ofRing(LinearRing ring, Vector3d movedBy) {
MovedRing indRing = new MovedRing();
indRing.original = ring;
for (Vertex v : ring.getVertices()) {
Vector3d movedV = new Vector3d(v.getX() - movedBy.getX(), v.getY() - movedBy.getY(),
v.getZ() - movedBy.getZ());
indRing.addVertex(movedV);
}
return indRing;
}
public LinearRing getOriginal() {
return original;
}
public MovedRing() {
vertices = new ArrayList<>();
}
public void addVertex(Vector3d v) {
vertices.add(v);
}
public List getVertices() {
return vertices;
}
/**
* Checks whether a point is inside this ring. A point on the edge does count as
* inside.
*
* @param v the point.
* @return true if the point is inside or on an edge, false if it is outside.
*/
public boolean isPointInside(Vector3d v) {
// project to 2d ring
List projectedRing = new ArrayList<>();
Vector2d point;
Vector3d normal = calculateNormal();
double x = Math.abs(normal.getX());
double y = Math.abs(normal.getY());
double z = Math.abs(normal.getZ());
if (x >= y && x >= z) {
for (Vector3d vert : vertices) {
Vector2d projCoords = new Vector2d(vert.getY(), vert.getZ());
projectedRing.add(projCoords);
}
point = new Vector2d(v.getY(), v.getZ());
} else if (y >= x && y >= z) {
for (Vector3d vert : vertices) {
Vector2d projCoords = new Vector2d(vert.getX(), vert.getZ());
projectedRing.add(projCoords);
}
point = new Vector2d(v.getX(), v.getZ());
} else {
for (Vector3d vert : vertices) {
Vector2d projCoords = new Vector2d(vert.getX(), vert.getY());
projectedRing.add(projCoords);
}
point = new Vector2d(v.getX(), v.getY());
}
int t = -1;
for (int i = 0; i < projectedRing.size() - 1; i++) {
t = t * crossProdTest(point, projectedRing.get(i), projectedRing.get(i + 1));
if (t == 0) {
return true;
}
}
return t >= 0;
}
private int crossProdTest(Vector2d a, Vector2d b, Vector2d c) {
if (a.getY() == b.getY() && a.getY() == c.getY()) {
if ((b.getX() <= a.getX() && a.getX() <= c.getX()) || (c.getX() <= a.getX() && a.getX() <= b.getX())) {
return 0;
} else {
return 1;
}
}
if (a.getY() == b.getY() && a.getX() == b.getX()) {
return 0;
}
if (b.getY() > c.getY()) {
Vector2d temp = b;
b = c;
c = temp;
}
if (a.getY() <= b.getY() || a.getY() > c.getY()) {
return 1;
}
return calculateDelta(a, b, c);
}
private int calculateDelta(Vector2d a, Vector2d b, Vector2d c) {
double delta = (b.getX() - a.getX()) * (c.getY() - a.getY()) - (b.getY() - a.getY()) * (c.getX() - a.getX());
if (delta > 0) {
return -1;
} else if (delta < 0) {
return 1;
} else {
return 0;
}
}
/**
* Calculates the normal vector of the ring. Method by Newell. If the Newell
* method would return a (0, 0, 0) vector a cross product is formed from the
* first 3 vertices. If there are no 3 vertices available (1, 0, 0) is returned.
*
* @return the normal as a normalized vector
*/
public Vector3d calculateNormal() {
double[] coords = new double[3];
for (int i = 0; i < vertices.size() - 1; i++) {
Vector3d current = vertices.get(i + 0);
Vector3d next = vertices.get(i + 1);
coords[0] += (current.getZ() + next.getZ()) * (current.getY() - next.getY());
coords[1] += (current.getX() + next.getX()) * (current.getZ() - next.getZ());
coords[2] += (current.getY() + next.getY()) * (current.getX() - next.getX());
}
if (coords[0] == 0 && coords[1] == 0 && coords[2] == 0) {
// no valid normal vector found
if (vertices.size() < 3) {
// no three points, return x-axis
return new Vector3d(1, 0, 0);
}
Vector3d v1 = vertices.get(0);
Vector3d v2 = vertices.get(1);
Vector3d v3 = vertices.get(2);
return calculateNormalWithCross(v1, v2, v3);
}
Vector3d v = new Vector3d(coords);
v.normalize();
return v;
}
private Vector3d calculateNormalWithCross(Vector3d v1, Vector3d v2, Vector3d v3) {
Vector3d dir1 = v2.minus(v1);
Vector3d dir2 = v3.minus(v1);
Vector3d cross = dir1.cross(dir2);
return cross.normalize();
}
}