Chris@313: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@313: 
Chris@313: /*
Chris@313:     Sonic Visualiser
Chris@313:     An audio file viewer and annotation editor.
Chris@313:     Centre for Digital Music, Queen Mary, University of London.
Chris@313:     
Chris@313:     This program is free software; you can redistribute it and/or
Chris@313:     modify it under the terms of the GNU General Public License as
Chris@313:     published by the Free Software Foundation; either version 2 of the
Chris@313:     License, or (at your option) any later version.  See the file
Chris@313:     COPYING included with this distribution for more information.
Chris@313: */
Chris@313: 
Chris@313: #include "ContinuousSynth.h"
Chris@313: 
Chris@313: #include "base/Debug.h"
Chris@318: #include "system/System.h"
Chris@313: 
Chris@313: #include <cmath>
Chris@313: 
rmb456@323: ContinuousSynth::ContinuousSynth(int channels, int sampleRate, int blockSize, int waveType) :
Chris@313:     m_channels(channels),
Chris@313:     m_sampleRate(sampleRate),
Chris@313:     m_blockSize(blockSize),
Chris@313:     m_prevF0(-1.f),
rmb456@323:     m_phase(0.0),
Chris@326:     m_wavetype(waveType) // 0: 3 sinusoids, 1: 1 sinusoid, 2: sawtooth, 3: square
Chris@313: {
Chris@313: }
Chris@313: 
Chris@313: ContinuousSynth::~ContinuousSynth()
Chris@313: {
Chris@313: }
Chris@313: 
Chris@313: void
Chris@313: ContinuousSynth::reset()
Chris@313: {
Chris@313:     m_phase = 0;
Chris@313: }
Chris@313: 
Chris@313: void
Chris@313: ContinuousSynth::mix(float **toBuffers, float gain, float pan, float f0)
Chris@313: {
Chris@313:     if (f0 == 0.f) f0 = m_prevF0;
Chris@313: 
Chris@313:     bool wasOn = (m_prevF0 > 0.f);
Chris@313:     bool nowOn = (f0 > 0.f);
Chris@313: 
Chris@313:     if (!nowOn && !wasOn) {
justin@327:     m_phase = 0;
justin@327:     return;
Chris@313:     }
Chris@313: 
Chris@315:     int fadeLength = 100; // samples
Chris@313: 
Chris@313:     float *levels = new float[m_channels];
Chris@313:     
Chris@313:     for (int c = 0; c < m_channels; ++c) {
justin@327:     levels[c] = gain * 0.5; // scale gain otherwise too loud compared to source
Chris@313:     }
Chris@313:     if (pan != 0.0 && m_channels == 2) {
justin@327:     levels[0] *= 1.0 - pan;
justin@327:     levels[1] *= pan + 1.0;
Chris@313:     }
Chris@313: 
Chris@315: //    cerr << "ContinuousSynth::mix: f0 = " << f0 << " (from " << m_prevF0 << "), phase = " << m_phase << endl;
Chris@313: 
Chris@313:     for (int i = 0; i < m_blockSize; ++i) {
Chris@313: 
Chris@315:         double fHere = (nowOn ? f0 : m_prevF0);
Chris@315: 
Chris@315:         if (wasOn && nowOn && (f0 != m_prevF0) && (i < fadeLength)) {
Chris@315:             // interpolate the frequency shift
Chris@315:             fHere = m_prevF0 + ((f0 - m_prevF0) * i) / fadeLength;
Chris@315:         }
Chris@315: 
Chris@315:         double phasor = (fHere * 2 * M_PI) / m_sampleRate;
Chris@315:     
rmb456@323:         m_phase = m_phase + phasor;
Chris@313: 
Chris@318:         int harmonics = (m_sampleRate / 4) / fHere - 1;
Chris@318:         if (harmonics < 1) harmonics = 1;
Chris@313: 
justin@327:         switch (m_wavetype) {
Chris@326:         case 1:
Chris@326:             harmonics = 1;
Chris@326:             break;
Chris@326:         case 2:
Chris@326:             break;
Chris@326:         case 3:
Chris@326:             break;
Chris@326:         default:
Chris@326:             harmonics = 3;
Chris@326:             break;
justin@327:         }
rmb456@323: 
rmb456@323: 
Chris@318:         for (int h = 0; h < harmonics; ++h) {
rmb456@323: 
Chris@326:             double v = 0;
Chris@326:             double hn = 0;
Chris@326:             double hp = 0;
rmb456@323: 
Chris@326:             switch (m_wavetype) {
Chris@326:             case 1: // single sinusoid
Chris@326:                 v = sin(m_phase);
Chris@326:                 break;
Chris@326:             case 2: // sawtooth
Chris@326:                 if (h != 0) {
justin@325:                     hn = h + 1;
rmb456@323:                     hp = m_phase * hn;
Chris@326:                     v = -(1.0 / M_PI) * sin(hp) / hn;
Chris@326:                 } else {
Chris@326:                     v = 0.5;
Chris@326:                 }
Chris@326:                 break;
Chris@326:             case 3: // square
Chris@326:                 hn = h*2 + 1;
Chris@326:                 hp = m_phase * hn;
Chris@326:                 v = sin(hp) / hn;
Chris@326:                 break;
Chris@326:             default: // 3 sinusoids
Chris@326:                 hn = h + 1;
Chris@326:                 hp = m_phase * hn;
Chris@326:                 v = sin(hp) / hn;
Chris@326:                 break;
Chris@326:             }
Chris@318: 
Chris@318:             if (!wasOn && i < fadeLength) {
Chris@318:                 // fade in
Chris@318:                 v = v * (i / double(fadeLength));
Chris@318:             } else if (!nowOn) {
Chris@318:                 // fade out
Chris@318:                 if (i > fadeLength) v = 0;
Chris@318:                 else v = v * (1.0 - (i / double(fadeLength)));
Chris@318:             }
Chris@318: 
Chris@318:             for (int c = 0; c < m_channels; ++c) {
Chris@318:                 toBuffers[c][i] += levels[c] * v;
Chris@318:             }
Chris@318:         }
justin@327:     }    
Chris@313: 
Chris@313:     m_prevF0 = f0;
Chris@313: 
Chris@313:     delete[] levels;
Chris@313: }
Chris@313: