KickerOsc.h

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/*
 * KickerOsc.h - alternative sweeping oscillator
 *
 * Copyright (c) 2006-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
 * Copyright (c) 2014 grejppi <grejppi/at/gmail.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 KICKER_OSC_H
#define KICKER_OSC_H
 
#include <cmath>
 
#include "DspEffectLibrary.h"
#include "Oscillator.h"
 
#include "lmms_math.h"
 
namespace lmms
{
 
 
template<class FX = DspEffectLibrary::StereoBypass>
class KickerOsc
{
public:
    KickerOsc( const FX & fx, const float start, const float end, const float noise, const float offset, 
        const float slope, const float env, const float diststart, const float distend, const float length ) :
        m_phase( offset ),
        m_startFreq( start ),
        m_endFreq( end ),
        m_noise( noise ),
        m_slope( slope ),
        m_env( env ),
        m_distStart( diststart ),
        m_distEnd( distend ),
        m_hasDistEnv( diststart != distend ),
        m_length( length ),
        m_FX( fx ),
        m_counter( 0 ),
        m_freq( start )
    {
    }
 
    virtual ~KickerOsc() = default;
 
    void update( SampleFrame* buf, const f_cnt_t frames, const float sampleRate )
    {
        for( f_cnt_t frame = 0; frame < frames; ++frame )
        {
            const double gain = 1 - fastPow((m_counter < m_length) ? m_counter / m_length : 1, m_env);
            const sample_t s = ( Oscillator::sinSample( m_phase ) * ( 1 - m_noise ) ) + ( Oscillator::noiseSample( 0 ) * gain * gain * m_noise );
            buf[frame][0] = s * gain;
            buf[frame][1] = s * gain;
            
            // update distortion envelope if necessary
            if( m_hasDistEnv && m_counter < m_length )
            {
                float thres = std::lerp(m_distStart, m_distEnd, m_counter / m_length);
                m_FX.leftFX().setThreshold( thres );
                m_FX.rightFX().setThreshold( thres );
            }
            
            m_FX.nextSample( buf[frame][0], buf[frame][1] );
            m_phase += m_freq / sampleRate;
 
            const double change = (m_counter < m_length) ? ((m_startFreq - m_endFreq) * (1 - fastPow(m_counter / m_length, m_slope))) : 0;
            m_freq = m_endFreq + change;
            ++m_counter;
        }
    }
 
 
private:
    float m_phase;
    const float m_startFreq;
    const float m_endFreq;
    const float m_noise;
    const float m_slope;
    const float m_env;
    const float m_distStart;
    const float m_distEnd;
    const bool m_hasDistEnv;
    const float m_length;
    FX m_FX;
 
    unsigned long m_counter;
    double m_freq;
 
};
 
 
} // namespace lmms
 
#endif