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• Polygon.java

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/*
 * Copyright (C) 2014 Timo Vesalainen
 *
 * 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, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */
package org.vesalainen.math;

import java.io.Serializable;
import org.ejml.data.DenseMatrix64F;

/**
 * 
 * @author Timo Vesalainen
 */
public class Polygon implements Serializable
{
    private static final long serialVersionUID = 1L;

    public final DenseMatrix64F points;
    public final Rect bounds = new Rect();

    public Polygon()
    {
        this(new DenseMatrix64F(0, 2));
    }

    public Polygon(DenseMatrix64F points)
    {
        assert points.numCols == 2;
        this.points = points;
        Matrices.removeEqualRows(points);
        updateBounds();
    }
    protected void copy(Polygon oth)
    {
        points.setReshape(oth.points);
        bounds.set(oth.bounds);
    }
    protected final void updateBounds()
    {
        bounds.reset();
        int len = points.numRows;
        double[] d = points.data;
        for (int ii=0;iiPNPOLY - Point Inclusion in Polygon Test W. Randolph Franklin (WRF)
     */
    public boolean isInside(double testx, double testy)
    {
        if (!bounds.isInside(testx, testy))
        {
            return false;
        }
        return isRawHit(points, testx, testy);
    }
    /**
     * Returns true if point is inside a polygon.
     * 
Doesn't check the bounding rectangle!
     * @param testx
     * @param testy
     * @return 
     * @see PNPOLY - Point Inclusion in Polygon Test W. Randolph Franklin (WRF)
     */
    public static boolean isRawHit(DenseMatrix64F points, double testx, double testy)
    {
        boolean c = false;
        int nvert = points.numRows;
        int i, j;
        double[] d = points.data;
        for (i = 0, j = nvert - 1; i < nvert; j = i++)
        {
            if (((d[2*i+1] > testy) != (d[2*j+1] > testy))
                    && (testx < (d[2*j] - d[2*i]) * (testy - d[2*i+1]) / (d[2*j+1] - d[2*i+1]) + d[2*i]))
            {
                c = !c;
            }
        }
        return c;
    }
    /**
     * Returns true if given point is vertex.
     * 
This is mainly for testing!
     * @param x
     * @param y
     * @return 
     */
    boolean isVertex(double x, double y)
    {
        int cnt = points.numRows;
        double[] d = points.data;
        for (int ii=0;ii