AlgoAreaPoints3D.java example

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geogebra-master
/* 
GeoGebra - Dynamic Mathematics for Everyone
http://www.geogebra.org

This file is part of GeoGebra.

This program is free software; you can redistribute it and/or modify it 
under the terms of the GNU General Public License as published by 
the Free Software Foundation.

 */

/*
 * Area of polygon P[0], ..., P[n]
 *
 */

package org.geogebra.common.geogebra3D.kernel3D.algos;

import org.geogebra.common.geogebra3D.kernel3D.geos.GeoPolygon3D;
import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.Matrix.CoordSys;
import org.geogebra.common.kernel.algos.AlgoAreaPoints;
import org.geogebra.common.kernel.algos.AlgoPolygon;
import org.geogebra.common.kernel.geos.GeoPoint;
import org.geogebra.common.kernel.kernelND.GeoPointND;

public class AlgoAreaPoints3D extends AlgoAreaPoints {

	public AlgoAreaPoints3D(Construction cons, String label, GeoPointND[] P) {
		super(cons, label, P);
	}

	private CoordSys coordSys;
	private GeoPoint[] points2D;

	@Override
	protected void createOutput(Construction cons1) {
		super.createOutput(cons1);
		coordSys = new CoordSys(2);
		points2D = new GeoPoint[P.length];
		for (int i = 0; i < P.length; i++) {
			points2D[i] = new GeoPoint(cons1, true);
		}
	}

	private double[] tmpCoords;

	@Override
	protected void initCoords() {
		tmpCoords = new double[4];
	}

	@Override
	public final void compute() {
		if (GeoPolygon3D.updateCoordSys(coordSys, P, points2D, tmpCoords)) {
			area.setValue(Math.abs(AlgoPolygon.calcAreaWithSign(points2D)));
		} else {
			area.setUndefined();
		}
	}

}