QuadratureLfo.h

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/*
 * quadraturelfo.h - definition of QuadratureLfo class.
 *
 * 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 LMMS_QUADRATURE_LFO_H
#define LMMS_QUADRATURE_LFO_H
 
#include <numbers>
#include <cmath>
 
namespace lmms
{
 
 
class QuadratureLfo
{
public:
    QuadratureLfo( int sampleRate ) :
        m_frequency(0),
        m_phase(0),
        m_offset(std::numbers::pi * 0.5)
    {
        setSampleRate(sampleRate);
    }
 
    ~QuadratureLfo() = 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;
    }
 
 
    inline void restart()
    {
        m_phase = 0;
    }
 
 
    inline void setSampleRate ( int samplerate )
    {
        m_samplerate = samplerate;
        m_twoPiOverSr = 2 * std::numbers::pi_v<float> / samplerate;
        m_increment = m_frequency * m_twoPiOverSr;
    }
 
 
    inline void setOffset( double offsetVal )
    {
        m_offset = offsetVal;
    }
 
 
    void tick( float *l, float *r )
    {
        *l = std::sin(m_phase);
        *r = std::sin(m_phase + m_offset);
        m_phase += m_increment;
        m_phase = std::fmod(m_phase, 2 * std::numbers::pi);
    }
 
private:
    double m_frequency;
    double m_phase;
    double m_increment;
    double m_twoPiOverSr;
    double m_offset;
    int m_samplerate;
 
};
 
 
} // namespace lmms
 
#endif // LMMS_QUADRATURE_LFO_H