engine/src/core/com/jme3/math/Rectangle.java

/*
 * Copyright (c) 2009-2010 jMonkeyEngine
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
 *   may be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.jme3.math;

import com.jme3.export.*;
import java.io.IOException;


/**
 * 
 * <code>Rectangle</code> defines a finite plane within three dimensional space
 * that is specified via three points (A, B, C). These three points define a
 * triangle with the forth point defining the rectangle ((B + C) - A.
 * 
 * @author Mark Powell
 * @author Joshua Slack
 */

public final class Rectangle implements Savable, Cloneable, java.io.Serializable {

    static final long serialVersionUID = 1;

    private Vector3f a, b, c;

    /**
     * Constructor creates a new <code>Rectangle</code> with no defined corners.
     * A, B, and C must be set to define a valid rectangle.
     * 
     */
    public Rectangle() {
        a = new Vector3f();
        b = new Vector3f();
        c = new Vector3f();
    }

    /**
     * Constructor creates a new <code>Rectangle</code> with defined A, B, and C
     * points that define the area of the rectangle.
     * 
     * @param a
     *            the first corner of the rectangle.
     * @param b
     *            the second corner of the rectangle.
     * @param c
     *            the third corner of the rectangle.
     */
    public Rectangle(Vector3f a, Vector3f b, Vector3f c) {
        this.a = a;
        this.b = b;
        this.c = c;
    }

    /**
     * <code>getA</code> returns the first point of the rectangle.
     * 
     * @return the first point of the rectangle.
     */
    public Vector3f getA() {
        return a;
    }

    /**
     * <code>setA</code> sets the first point of the rectangle.
     * 
     * @param a
     *            the first point of the rectangle.
     */
    public void setA(Vector3f a) {
        this.a = a;
    }

    /**
     * <code>getB</code> returns the second point of the rectangle.
     * 
     * @return the second point of the rectangle.
     */
    public Vector3f getB() {
        return b;
    }

    /**
     * <code>setB</code> sets the second point of the rectangle.
     * 
     * @param b
     *            the second point of the rectangle.
     */
    public void setB(Vector3f b) {
        this.b = b;
    }

    /**
     * <code>getC</code> returns the third point of the rectangle.
     * 
     * @return the third point of the rectangle.
     */
    public Vector3f getC() {
        return c;
    }

    /**
     * <code>setC</code> sets the third point of the rectangle.
     * 
     * @param c
     *            the third point of the rectangle.
     */
    public void setC(Vector3f c) {
        this.c = c;
    }

    /**
     * <code>random</code> returns a random point within the plane defined by:
     * A, B, C, and (B + C) - A.
     * 
     * @return a random point within the rectangle.
     */
    public Vector3f random() {
        return random(null);
    }

    /**
     * <code>random</code> returns a random point within the plane defined by:
     * A, B, C, and (B + C) - A.
     * 
     * @param result
     *            Vector to store result in
     * @return a random point within the rectangle.
     */
    public Vector3f random(Vector3f result) {
        if (result == null) {
            result = new Vector3f();
        }

        float s = FastMath.nextRandomFloat();
        float t = FastMath.nextRandomFloat();

        float aMod = 1.0f - s - t;
        result.set(a.mult(aMod).addLocal(b.mult(s).addLocal(c.mult(t))));
        return result;
    }

    public void write(JmeExporter e) throws IOException {
        OutputCapsule capsule = e.getCapsule(this);
        capsule.write(a, "a", Vector3f.ZERO);
        capsule.write(b, "b", Vector3f.ZERO);
        capsule.write(c, "c", Vector3f.ZERO);
    }

    public void read(JmeImporter e) throws IOException {
        InputCapsule capsule = e.getCapsule(this);
        a = (Vector3f) capsule.readSavable("a", Vector3f.ZERO.clone());
        b = (Vector3f) capsule.readSavable("b", Vector3f.ZERO.clone());
        c = (Vector3f) capsule.readSavable("c", Vector3f.ZERO.clone());
    }

    @Override
    public Rectangle clone() {
        try {
            Rectangle r = (Rectangle) super.clone();
            r.a = a.clone();
            r.b = b.clone();
            r.c = c.clone();
            return r;
        } catch (CloneNotSupportedException e) {
            throw new AssertionError();
        }
    }
}