Lfo.h

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/*
 * lfo.h - declaration of Lfo class, a simple sine lfo
 *
 * Copyright (c) 2014 David French <dave/dot/french3/at/googlemail/dot/com>
 *
 * This file is part of LMMS - https://lmms.io
 *
 * 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 (see COPYING); if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301 USA.
 *
 */
 
#ifndef LFO_H
#define LFO_H
 
#include <cmath>
#include <numbers>
 
namespace lmms
{
 
 
class Lfo
{
public:
        Lfo( int samplerate );
        ~Lfo() = default;
 
 
 
 
        inline void setFrequency( double frequency )
        {
                if( frequency < 0 || frequency > ( m_samplerate / 2.0 ) || frequency == m_frequency )
                {
                        return;
                }
                m_frequency = frequency;
                m_increment = m_frequency * m_twoPiOverSr;
 
                m_phase = std::fmod(m_phase, 2 * std::numbers::pi_v<float>);
        }
 
 
 
 
        inline void setSampleRate ( int samplerate )
        {
                m_samplerate = samplerate;
                m_twoPiOverSr = 2 * std::numbers::pi_v<float> / samplerate;
                m_increment = m_frequency * m_twoPiOverSr;
        }
 
 
 
 
        float tick();
 
private:
        double m_frequency;
        double m_phase;
        double m_increment;
        double m_twoPiOverSr;
        int m_samplerate;
};
 
 
} // namespace lmms
 
#endif // LFO_H