/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2006-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library 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;
* version 2.1 of the License.
*
* This library 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.
*/
package org.geotools.geometry.iso.util.interpolation;
import java.awt.geom.Point2D;
import java.util.ArrayList;
import org.geotools.geometry.iso.util.algorithm2D.AlgoPoint2D;
import org.geotools.geometry.iso.util.interpolation.ITP_Interpolation.Point3d;
/**
* @author roehrig
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*
*
*
* @source $URL$
*/
public class PointNeighboursGradients {
Point3d mP;
ITP_Interpolation.Point3d[] mNbrs;
public Point2D mGradXY;
public PointNeighboursGradients(Point3d p) {
this.mP = p;
}
public PointNeighboursGradients(Point3d p, Point3d[] nbrs) {
this.mP = p;
System.arraycopy(nbrs, 0, this.mNbrs, 0, nbrs.length);
this.mGradXY = null;
}
public void setAkimaGradient() {
int nnbr = this.mNbrs.length;
double a = 0.0;
double b = 0.0;
double c = 0.0;
for ( int i = 0 ; i < nnbr; ++i) {
Point2D dp0 = new Point2D.Double(this.mNbrs[i].x-this.mP.x, this.mNbrs[i].y-this.mP.y);
double dz0 = this.mNbrs[i].z - this.mP.z;
for ( int j = i + 1 ; j <= this.mNbrs.length - 1; ++j) {
Point2D dp1 = new Point2D.Double(this.mNbrs[j].x-this.mP.x, this.mNbrs[j].y-this.mP.y);
double delta_c = AlgoPoint2D.cross(dp0,dp1);
if ( delta_c != 0.0 ) {
double dz1 = this.mNbrs[j].z - this.mP.z;
double delta_a = dp0.getY() * dz1 - dp1.getY() * dz0;
double delta_b = dp1.getX() * dz0 - dp0.getX() * dz1;
if ( delta_c < 0.0 ) {
delta_a = -delta_a;
delta_b = -delta_b;
delta_c = -delta_c;
}
a += delta_a;
b += delta_b;
c += delta_c;
}
}
}
this.mGradXY = new Point2D.Double(-a / c, -b / c);
}
public void setClosestPoints(ArrayList<Point3d> pIn, int nnbr) {
ArrayList<Point3d> nbrs = new ArrayList<Point3d>();
double[] nbrDist = new double[nnbr];
for ( int i = 0 ; i < nnbr; ++i) {
nbrDist[i] = Double.MAX_VALUE;
}
for ( int i = 0, j = 0 ; i < pIn.size(); ++i) {
Point3d p1 = pIn.get(i);
if ( this.mP != p1 ) {
double dist = (this.mP.x-p1.x)*(this.mP.x-p1.x) + (this.mP.y-p1.y)*(this.mP.y-p1.y);
if ( j < nnbr ) {
nbrDist[j] = dist;
nbrs.add(p1);
} else {
for ( int k = 0 ; k < nnbr; ++k) {
if ( dist < nbrDist[k] ) {
nbrDist[k] = dist;
nbrs.add(p1);
break;
}
}
}
j += 1;
}
}
this.mNbrs = new Point3d[nbrs.size()];
for (int i=0; i<nbrs.size(); ++i) this.mNbrs[i] = nbrs.get(i);
}
}