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80 lines
1.7 KiB
C++
80 lines
1.7 KiB
C++
/*
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* lfo.cpp - defination of Lfo class.
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*
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* Copyright (c) 2014 David French <dave/dot/french3/at/googlemail/dot/com>
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*
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* This file is part of LMMS - http://lmms.io
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program (see COPYING); if not, write to the
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* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301 USA.
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*
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*/
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#include "lfo.h"
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#include <math.h>
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Lfo::Lfo( int samplerate )
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{
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m_samplerate = samplerate;
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m_twoPiOverSr = TWOPI / samplerate;
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}
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void Lfo::setFrequency( double frequency )
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{
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if( frequency < 0 || frequency > ( m_samplerate / 2.0 ) || frequency == m_frequency )
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{
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return;
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}
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m_frequency = frequency;
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m_increment = m_frequency * m_twoPiOverSr;
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}
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void Lfo::setAmplitude( float amplitude )
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{
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if( amplitude < 0.0 || amplitude > 1.0 )
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{
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return;
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}
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m_amplitude = amplitude;
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}
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float Lfo::tick()
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{
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float output = ( float )sin( m_phase );
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m_phase += m_increment;
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if( m_phase >= TWOPI )
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{
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m_phase -= TWOPI;
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}
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if( m_amplitude > 0.0001 )
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{
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return ( ( output + 1.0 ) / 2.0 ) * m_amplitude;
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} else
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{
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return 1;
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}
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}
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