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Merge pull request #789 from TomHarte/OPLLDrums

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Softens OPLL tremolo and vibrato; adds drum damping.
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Thomas Harte 2020-05-10 15:51:34 -04:00 committed by GitHub
commit d964ebd4c1
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4 changed files with 28 additions and 11 deletions
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3
Components/OPx/Implementation/EnvelopeGenerator.hpp
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@ -84,7 +84,8 @@ template <int envelope_precision, int period_precision> class EnvelopeGenerator
@returns The current attenuation from this envelope generator. This is independent of the envelope precision.
*/
int attenuation() const {
return (attenuation_ + tremolo_) << 3;
// TODO: if this envelope is fully released, should tremolo still be able to vocalise it?
return (attenuation_ << 3) + tremolo_;
}
/*!

6
Components/OPx/Implementation/PhaseGenerator.hpp
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@ -26,7 +26,7 @@ template <int precision> class PhaseGenerator {
Advances the phase generator a single step, given the current state of the low-frequency oscillator, @c oscillator.
*/
void update(const LowFrequencyOscillator &oscillator) {
constexpr int vibrato_shifts[8] = {3, 1, 0, 1, 3, 1, 0, 1};
constexpr int vibrato_shifts[4] = {3, 1, 0, 1};
constexpr int vibrato_signs[2] = {1, -1};
// Get just the top three bits of the period_.
@ -35,10 +35,10 @@ template <int precision> class PhaseGenerator {
// Cacluaute applicable vibrato as a function of (i) the top three bits of the
// oscillator period; (ii) the current low-frequency oscillator vibrato output; and
// (iii) whether vibrato is enabled.
const int vibrato = (top_freq >> vibrato_shifts[oscillator.vibrato]) * vibrato_signs[oscillator.vibrato >> 2] * enable_vibrato_;
const int vibrato = (top_freq >> vibrato_shifts[oscillator.vibrato & 3]) * vibrato_signs[oscillator.vibrato >> 2] * enable_vibrato_;
// Apply phase update with vibrato from the low-frequency oscillator.
phase_ += multiple_ * (period_ + vibrato) << octave_;
phase_ += (multiple_ * ((period_ << 1) + vibrato) << octave_) >> 1;
}

26
Components/OPx/OPLL.cpp
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@ -28,6 +28,14 @@ OPLL::OPLL(Concurrency::DeferringAsyncTaskQueue &task_queue, int audio_divider,
phase_generators_[6 + 9].reset();
});
// Set the other drums to damp, but only the TomTom to affect phase.
rhythm_envelope_generators_[TomTom].set_should_damp([this] {
phase_generators_[8 + 9].reset();
});
rhythm_envelope_generators_[Snare].set_should_damp({});
rhythm_envelope_generators_[Cymbal].set_should_damp({});
rhythm_envelope_generators_[HighHat].set_should_damp({});
// Crib the proper rhythm envelope generator settings by installing
// the rhythm instruments and copying them over.
rhythm_mode_enabled_ = true;
@ -45,7 +53,7 @@ OPLL::OPLL(Concurrency::DeferringAsyncTaskQueue &task_queue, int audio_divider,
// Return to ordinary default mode.
rhythm_mode_enabled_ = false;
// Set up proper damping management.
// Set up damping for the melodic channels.
for(int c = 0; c < 9; ++c) {
envelope_generators_[c].set_should_damp([this, c] {
// Propagate attack mode to the modulator, and reset both phases.
@ -372,10 +380,12 @@ void OPLL::update_all_channels() {
// TODO: verify attenuation scales pervasively below.
#define ATTENUATION(x) ((x) << 7)
int OPLL::melodic_output(int channel) {
// The modulator always updates after the carrier, oddly enough. So calculate actual output first, based on the modulator's last value.
auto carrier = WaveformGenerator<period_precision>::wave(channels_[channel].carrier_waveform, phase_generators_[channel].scaled_phase(), channels_[channel].modulator_output);
carrier += envelope_generators_[channel].attenuation() + (channels_[channel].attenuation << 7) + key_level_scalers_[channel].attenuation();
carrier += envelope_generators_[channel].attenuation() + ATTENUATION(channels_[channel].attenuation) + key_level_scalers_[channel].attenuation();
// Get the modulator's new value.
auto modulation = WaveformGenerator<period_precision>::wave(channels_[channel].modulator_waveform, phase_generators_[channel + 9].phase());
@ -394,7 +404,7 @@ int OPLL::bass_drum() {
modulation += rhythm_envelope_generators_[RhythmIndices::BassModulator].attenuation();
auto carrier = WaveformGenerator<period_precision>::wave(Waveform::Sine, phase_generators_[6].scaled_phase(), modulation);
carrier += rhythm_envelope_generators_[RhythmIndices::BassCarrier].attenuation() + (channels_[6].attenuation << 7);
carrier += rhythm_envelope_generators_[RhythmIndices::BassCarrier].attenuation() + ATTENUATION(channels_[6].attenuation);
return carrier.level();
}
@ -402,7 +412,7 @@ int OPLL::tom_tom() {
// Use modulator 8 and the 'instrument' selection for channel 8 as an attenuation.
auto tom_tom = WaveformGenerator<period_precision>::wave(Waveform::Sine, phase_generators_[8 + 9].phase());
tom_tom += rhythm_envelope_generators_[RhythmIndices::TomTom].attenuation();
tom_tom += channels_[8].instrument << 7;
tom_tom += ATTENUATION(channels_[8].instrument);
return tom_tom.level();
}
@ -410,7 +420,7 @@ int OPLL::snare_drum() {
// Use modulator 7 and the carrier attenuation level for channel 7.
LogSign snare = WaveformGenerator<period_precision>::snare(oscillator_, phase_generators_[7 + 9].phase());
snare += rhythm_envelope_generators_[RhythmIndices::Snare].attenuation();
snare += channels_[7].attenuation << 7;
snare += ATTENUATION(channels_[7].attenuation);
return snare.level();
}
@ -418,7 +428,7 @@ int OPLL::cymbal() {
// Use modulator 7, carrier 8 and the attenuation level for channel 8.
LogSign cymbal = WaveformGenerator<period_precision>::cymbal(phase_generators_[8].phase(), phase_generators_[7 + 9].phase());
cymbal += rhythm_envelope_generators_[RhythmIndices::Cymbal].attenuation();
cymbal += channels_[8].attenuation << 7;
cymbal += ATTENUATION(channels_[8].attenuation);
return cymbal.level();
}
@ -426,6 +436,8 @@ int OPLL::high_hat() {
// Use modulator 7, carrier 8 a and the 'instrument' selection for channel 7 as an attenuation.
LogSign high_hat = WaveformGenerator<period_precision>::high_hat(oscillator_, phase_generators_[8].phase(), phase_generators_[7 + 9].phase());
high_hat += rhythm_envelope_generators_[RhythmIndices::HighHat].attenuation();
high_hat += channels_[7].instrument << 7;
high_hat += ATTENUATION(channels_[7].instrument);
return high_hat.level();
}
#undef ATTENUATION

4
Outputs/Speaker/Implementation/SampleSource.hpp
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@ -63,6 +63,10 @@ class SampleSource {
a certain proportion of the allocated volume range. This commonly happens
in sample sources that use a time-multiplexed sound output — for example, if
one were to output only every other sample then it would return 0.5.
This is permitted to vary over time but there is no contract as to when it will be
used by a speaker. If it varies, it should do so very infrequently and only to
represent changes in hardware configuration.
*/
double get_average_output_peak() const { return 1.0; }
};