AlgoPlaneTwoLines.java example

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

import org.geogebra.common.geogebra3D.kernel3D.geos.GeoPlane3D;
import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.Kernel;
import org.geogebra.common.kernel.StringTemplate;
import org.geogebra.common.kernel.Matrix.CoordSys;
import org.geogebra.common.kernel.Matrix.Coords;
import org.geogebra.common.kernel.commands.Commands;
import org.geogebra.common.kernel.geos.GeoElement;
import org.geogebra.common.kernel.kernelND.GeoCoordSys2D;
import org.geogebra.common.kernel.kernelND.GeoLineND;

/**
 * 
 * Plane containing the two lines, if possible
 * 
 * @author mathieu
 *
 */
public class AlgoPlaneTwoLines extends AlgoElement3D {

	/** the 2D coord sys created */
	protected GeoCoordSys2D cs;

	/** 3D points */
	private GeoLineND a, b;

	/**
	 * create a plane joining lines, with label.
	 * 
	 * @param c
	 *            construction
	 * @param label
	 *            label of the polygon
	 * @param a
	 *            first point
	 * @param b
	 *            second point
	 */
	public AlgoPlaneTwoLines(Construction c, String label, GeoLineND a,
			GeoLineND b) {
		super(c);

		this.a = a;
		this.b = b;

		cs = new GeoPlane3D(c);

		// set input and output
		setInputOutput(new GeoElement[] { (GeoElement) a, (GeoElement) b },
				new GeoElement[] { (GeoElement) cs });

		compute();

		((GeoElement) cs).setLabel(label);

	}

	@Override
	public void compute() {

		CoordSys coordsys = cs.getCoordSys();

		if ((!a.isDefined()) || (!b.isDefined())) {
			coordsys.setUndefined();
			return;
		}

		Coords oa = a.getStartInhomCoords();
		Coords va = a.getDirectionInD3();

		Coords ob = b.getStartInhomCoords();
		Coords vb = b.getDirectionInD3();

		Coords vn = va.crossProduct(vb);
		Coords oo = ob.sub(oa);

		if (!Kernel.isZero(vn.dotproduct(oo))) {
			// lines are not in the same plane
			coordsys.setUndefined();
			return;
		}

		// recompute the coord sys
		coordsys.resetCoordSys();

		coordsys.addPoint(oa);
		coordsys.addVector(va);
		if (vn.isZero()) {
			// when lines are parallel
			coordsys.addVector(oo);
			vn = va.crossProduct(oo);
		} else {
			coordsys.addVector(vb);
		}

		if (coordsys.makeOrthoMatrix(false, false)) {
			if (coordsys.isDefined()) {
				coordsys.setEquationVector(oa, vn);
			}
		}

		// Application.debug(cs.getCoordSys().getMatrixOrthonormal().toString());

	}

	/**
	 * return the cs
	 * 
	 * @return the cs
	 */
	public GeoCoordSys2D getCoordSys() {
		return cs;
	}

	@Override
	public Commands getClassName() {
		return Commands.Plane;
	}

	@Override
	final public String toString(StringTemplate tpl) {
		return getLoc().getPlain("PlaneThroughAB", a.getLabel(tpl),
				b.getLabel(tpl));

	}

}