/*
* JGrass - Free Open Source Java GIS http://www.jgrass.org
* (C) HydroloGIS - www.hydrologis.com
*
* This library is free software; you can redistribute it and/or modify it under
* the terms of the GNU Library General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option) any
* later version.
*
* 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 Library General Public License for more
* details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; if not, write to the Free Foundation, Inc., 59
* Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.jgrasstools.gears.utils.math.interpolation.splines;
/**
* This is adapted from: http://www.cse.unsw.edu.au/~lambert/splines/CatmullRom.html
*
* @author Tim Lambert (http://www.cse.unsw.edu.au/~lambert/)
* @author Andrea Antonello (www.hydrologis.com)
*/
public class CatmullRom extends Bspline {
// Catmull-Rom spline is just like a B spline, only with a different basis
double b(int i, double t) {
switch (i) {
case -2:
return ((-t+2)*t-1)*t/2;
case -1:
return (((3*t-5)*t)*t+2)/2;
case 0:
return ((-3*t+4)*t+1)*t/2;
case 1:
return ((t-1)*t*t)/2;
}
return 0; //we only get here if an invalid i is specified
}
}