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Tweak yaw-shepard

This commit is contained in:
yaw-man 2022-08-19 16:18:51 -03:00
parent 9f50e9d40e
commit bdaa77dcf0
2 changed files with 10 additions and 8 deletions
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12
src/yaw-shepard/synth.cpp
View File

@ -12,7 +12,7 @@ static constexpr double getAmplitude( double hz )
{ {
if( hz < 20.0 ) return 0.0; if( hz < 20.0 ) return 0.0;
if( hz < 440.0 ) return hz / 440.0; if( hz < 440.0 ) return hz / 440.0;
if( hz < 16000.0 ) return (16000.0 - hz) / 15560.0; if( hz < 10000.0 ) return (10000.0 - hz) / 9560.0;
return 0.0; return 0.0;
} }
@ -42,14 +42,14 @@ void Synth::process(float* output, const uint32_t frames)
//Don't bother rendering anything over the Nyquist rate. //Don't bother rendering anything over the Nyquist rate.
if( hz > hzNyq ) break; if( hz > hzNyq ) break;
output[i] += getAmplitude(hz) * sin(2.0 * M_PI * phase); output[i] += getAmplitude(hz) * (phase > 0.5); // * sin(2.0 * M_PI * phase);
//Remember phase, move to higher overtone. //Remember phase, move to higher overtone.
phases[(voice + idxFund) & VOICE_MASK] = phase; phases[(voice + idxFund) & VOICE_MASK] = phase;
hz *= ratio; hz *= ratio;
} }
output[i] *= volume; output[i] *= volume / static_cast<double>(NUM_VOICES);
} }
//Make timbre cyclical. //Make timbre cyclical.
@ -81,7 +81,7 @@ void Synth::process(float* output, const uint32_t frames)
void Synth::setSampleRate(double oldRate, double newRate){ void Synth::setSampleRate(double oldRate, double newRate){
sampleInterval = 1.0 / newRate; sampleInterval = 1.0 / newRate;
hzNyq = newRate / 2; hzNyq = newRate / 2;
ratioSlewRate *= newRate / oldRate; ratioSlewRate = pow(ratioSlewRate, oldRate / newRate);
hzShift = pow(hzShift, newRate / oldRate); hzShift = pow(hzShift, newRate / oldRate);
} }
@ -92,11 +92,13 @@ void Synth::setFrequencyShift(double in){
hzShift = exp2(2.0 * (in - 0.5) * sampleInterval); hzShift = exp2(2.0 * (in - 0.5) * sampleInterval);
} }
static constexpr double minRatio = 1.0;
static constexpr double maxRatio = 3.0;
//Slew to given ratio. //Slew to given ratio.
//0 : next voice is one fifth above previous voice. //0 : next voice is one fifth above previous voice.
//1 : next voice is one octave above previous voice. //1 : next voice is one octave above previous voice.
void Synth::setTargetRatio(double in){ void Synth::setTargetRatio(double in){
targetRatio = 1.5 + in * 0.5; targetRatio = minRatio + in * (maxRatio - minRatio);
} }
void Synth::setVolume(double in){ void Synth::setVolume(double in){

6
src/yaw-shepard/synth.h
View File

@ -7,8 +7,8 @@ struct Voice
double phase; double phase;
}; };
constexpr int NUM_VOICES = 256; constexpr unsigned int NUM_VOICES = 64;
constexpr uchar VOICE_MASK = 0xFF; constexpr unsigned int VOICE_MASK = NUM_VOICES - 1;
class Synth class Synth
{ {
@ -25,7 +25,7 @@ private:
//Phase of each voice, considered as a period function on the unit interval. //Phase of each voice, considered as a period function on the unit interval.
std::array<double, NUM_VOICES> phases = {0}; std::array<double, NUM_VOICES> phases = {0};
//Index of lowest voice in phase array. //Index of lowest voice in phase array.
uchar idxFund = 0; unsigned int idxFund = 0;
float volume = 0.0f; float volume = 0.0f;
double hzFund = 32.7; double hzFund = 32.7;
double hzShift = 1.0; double hzShift = 1.0;