Java Angle Reduce reduceAngle(double theta)

Description

reduce Angle

License

Open Source License

Declaration

public static double reduceAngle(double theta) 

Method Source Code

//package com.java2s;
/*//from w  w w. j  a v a 2  s .c  o m
 *   __               .__       .__  ._____.           
 * _/  |_  _______  __|__| ____ |  | |__\_ |__   ______
 * \   __\/  _ \  \/  /  |/ ___\|  | |  || __ \ /  ___/
 *  |  | (  <_> >    <|  \  \___|  |_|  || \_\ \\___ \ 
 *  |__|  \____/__/\_ \__|\___  >____/__||___  /____  >
 *                   \/       \/             \/     \/ 
 *
 * Copyright (c) 2006-2011 Karsten Schmidt
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * http://creativecommons.org/licenses/LGPL/2.1/
 * 
 * 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

public class Main {
    /**
     * PI
     */
    public static final float PI = 3.14159265358979323846f;
    /**
     * PI/2
     */
    public static final float HALF_PI = PI / 2;
    /**
     * PI*2
     */
    public static final float TWO_PI = PI * 2;

    public static double reduceAngle(double theta) {
        theta %= TWO_PI;
        if (Math.abs(theta) > PI) {
            theta = theta - TWO_PI;
        }
        if (Math.abs(theta) > HALF_PI) {
            theta = PI - theta;
        }
        return theta;
    }

    /**
     * Reduces the given angle into the -PI/4 ... PI/4 interval for faster
     * computation of sin/cos. This method is used by {@link #sin(float)} &
     * {@link #cos(float)}.
     * 
     * @param theta
     *            angle in radians
     * @return reduced angle
     * @see #sin(float)
     * @see #cos(float)
     */
    public static float reduceAngle(float theta) {
        theta %= TWO_PI;
        if (Math.abs(theta) > PI) {
            theta = theta - TWO_PI;
        }
        if (Math.abs(theta) > HALF_PI) {
            theta = PI - theta;
        }
        return theta;
    }
}

Related

1. reduceAngle(double theta)
2. reduceAngle(float angle)
3. reduceAngle(float theta)