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Java OpenGL Math Library
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/*
 * The MIT License
 *
 * Copyright (c) 2016-2024 JOML
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package org.joml.sampling;

/**
 * Internal Math class used by the sampling package.
 * 
 * @author Kai Burjack
 */
class Math extends org.joml.Math {

    static final double PI = java.lang.Math.PI;
    static final double PI2 = PI * 2.0;
    static final double PIHalf = PI * 0.5;
    private static final double ONE_OVER_PI = 1.0 / PI;
    private static final double s5 = Double.longBitsToDouble(4523227044276562163L);
    private static final double s4 = Double.longBitsToDouble(-4671934770969572232L);
    private static final double s3 = Double.longBitsToDouble(4575957211482072852L);
    private static final double s2 = Double.longBitsToDouble(-4628199223918090387L);
    private static final double s1 = Double.longBitsToDouble(4607182418589157889L);

    /**
     * Reference: http://www.java-gaming.org/
     * 
     * @author roquendm
     */
    static double sin_roquen_9(double v) {
        double i = java.lang.Math.rint(v * ONE_OVER_PI);
        double x = v - i * Math.PI;
        double qs = 1 - 2 * ((int) i & 1);
        double x2 = x * x;
        double r;
        x = qs * x;
        r = s5;
        r = r * x2 + s4;
        r = r * x2 + s3;
        r = r * x2 + s2;
        r = r * x2 + s1;
        return x * r;
    }

}