Random.cpp

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/*
 * Hydrogen
 * Copyright(c) 2008-2024 The hydrogen development team [hydrogen-devel@lists.sourceforge.net]
 *
 * http://www.hydrogen-music.org
 *
 * 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 2 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 https://www.gnu.org/licenses
 *
 */
 
#include <core/Helpers/Random.h>
 
namespace H2Core {
 
float Random::getGaussian( float fStandardDeviation ) {
        // gaussian distribution -- dimss
        float x1, x2, w;
        do {
                x1 = 2.0 * ( ( ( float ) rand() ) / static_cast<float>(RAND_MAX) ) - 1.0;
                x2 = 2.0 * ( ( ( float ) rand() ) / static_cast<float>(RAND_MAX) ) - 1.0;
                w = x1 * x1 + x2 * x2;
        } while ( w >= 1.0 );
 
        w = sqrtf( ( -2.0 * logf( w ) ) / w );
        return x1 * w * fStandardDeviation + 0.0; // tunable
}
};