Reduces the given angle into the -PI/4 ... - Java java.lang

Java examples for java.lang:Math Value

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Description

Reduces the given angle into the -PI/4 ...

Demo Code

/*//from w ww .j  a v a  2s . 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
 */
//package com.java2s;

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 * 2f;

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

    /**
     * @param x
     * @return absolute value of x
     */
    public static final double abs(double x) {
        return x < 0 ? -x : x;
    }

    /**
     * @param x
     * @return absolute value of x
     */
    public static final float abs(float x) {
        return x < 0 ? -x : x;
    }

    /**
     * @param x
     * @return absolute value of x
     */
    public static final int abs(int x) {
        int y = x >> 31;
        return (x ^ y) - y;
    }
}

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