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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
Sonic Visualiser
An audio file viewer and annotation editor.
Centre for Digital Music, Queen Mary, University of London.
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. See the file
COPYING included with this distribution for more information.
*/
#include "ContinuousSynth.h"
#include "base/Debug.h"
#include "system/System.h"
#include <cmath>
namespace sv {
ContinuousSynth::ContinuousSynth(int channels, sv_samplerate_t sampleRate, sv_frame_t blockSize, int waveType) :
m_channels(channels),
m_sampleRate(sampleRate),
m_blockSize(blockSize),
m_prevF0(-1.0),
m_phase(0.0),
m_wavetype(waveType) // 0: 3 sinusoids, 1: 1 sinusoid, 2: sawtooth, 3: square
{
}
ContinuousSynth::~ContinuousSynth()
{
}
void
ContinuousSynth::reset()
{
m_phase = 0;
}
void
ContinuousSynth::mix(float **toBuffers, float gain, float pan, float f0f)
{
double f0(f0f);
if (f0 == 0.0) f0 = m_prevF0;
bool wasOn = (m_prevF0 > 0.0);
bool nowOn = (f0 > 0.0);
if (!nowOn && !wasOn) {
m_phase = 0;
return;
}
sv_frame_t fadeLength = 100;
float *levels = new float[m_channels];
for (int c = 0; c < m_channels; ++c) {
levels[c] = gain * 0.5f; // scale gain otherwise too loud compared to source
}
if (pan != 0.0 && m_channels == 2) {
levels[0] *= 1.0f - pan;
levels[1] *= pan + 1.0f;
}
// cerr << "ContinuousSynth::mix: f0 = " << f0 << " (from " << m_prevF0 << "), phase = " << m_phase << endl;
for (sv_frame_t i = 0; i < m_blockSize; ++i) {
double fHere = (nowOn ? f0 : m_prevF0);
if (wasOn && nowOn && (f0 != m_prevF0) && (i < fadeLength)) {
// interpolate the frequency shift
fHere = m_prevF0 + ((f0 - m_prevF0) * double(i)) / double(fadeLength);
}
double phasor = (fHere * 2 * M_PI) / m_sampleRate;
m_phase = m_phase + phasor;
int harmonics = int((m_sampleRate / 4) / fHere - 1);
if (harmonics < 1) harmonics = 1;
switch (m_wavetype) {
case 1:
harmonics = 1;
break;
case 2:
break;
case 3:
break;
default:
harmonics = 3;
break;
}
for (int h = 0; h < harmonics; ++h) {
double v = 0;
double hn = 0;
double hp = 0;
switch (m_wavetype) {
case 1: // single sinusoid
v = sin(m_phase);
break;
case 2: // sawtooth
if (h != 0) {
hn = h + 1;
hp = m_phase * hn;
v = -(1.0 / M_PI) * sin(hp) / hn;
} else {
v = 0.5;
}
break;
case 3: // square
hn = h*2 + 1;
hp = m_phase * hn;
v = sin(hp) / hn;
break;
default: // 3 sinusoids
hn = h + 1;
hp = m_phase * hn;
v = sin(hp) / hn;
break;
}
if (!wasOn && i < fadeLength) {
// fade in
v = v * (double(i) / double(fadeLength));
} else if (!nowOn) {
// fade out
if (i > fadeLength) v = 0;
else v = v * (1.0 - (double(i) / double(fadeLength)));
}
for (int c = 0; c < m_channels; ++c) {
toBuffers[c][i] += float(levels[c] * v);
}
}
}
m_prevF0 = f0;
delete[] levels;
}
} // end namespace sv
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