mirror of
https://github.com/TomHarte/CLK.git
synced 2024-06-30 22:29:56 +00:00
444 lines
16 KiB
C++
444 lines
16 KiB
C++
//
|
||
// OPLL.cpp
|
||
// Clock Signal
|
||
//
|
||
// Created by Thomas Harte on 03/05/2020.
|
||
// Copyright © 2020 Thomas Harte. All rights reserved.
|
||
//
|
||
|
||
#include "OPLL.hpp"
|
||
|
||
#include <cassert>
|
||
|
||
using namespace Yamaha::OPL;
|
||
|
||
OPLL::OPLL(Concurrency::AsyncTaskQueue<false> &task_queue, int audio_divider, bool is_vrc7):
|
||
OPLBase(task_queue), audio_divider_(audio_divider), is_vrc7_(is_vrc7) {
|
||
// Due to the way that sound mixing works on the OPLL, the audio divider may not
|
||
// be larger than 4.
|
||
assert(audio_divider <= 4);
|
||
|
||
// Setup the rhythm envelope generators.
|
||
|
||
// Treat the bass exactly as if it were a melodic channel.
|
||
rhythm_envelope_generators_[BassCarrier].set_should_damp([this] {
|
||
// Propagate attack mode to the modulator, and reset both phases.
|
||
rhythm_envelope_generators_[BassModulator].set_key_on(true);
|
||
phase_generators_[6 + 0].reset();
|
||
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;
|
||
install_instrument(6);
|
||
install_instrument(7);
|
||
install_instrument(8);
|
||
|
||
rhythm_envelope_generators_[BassCarrier] = envelope_generators_[6];
|
||
rhythm_envelope_generators_[BassModulator] = envelope_generators_[6 + 9];
|
||
rhythm_envelope_generators_[HighHat] = envelope_generators_[7 + 9];
|
||
rhythm_envelope_generators_[Cymbal] = envelope_generators_[8];
|
||
rhythm_envelope_generators_[TomTom] = envelope_generators_[8 + 9];
|
||
rhythm_envelope_generators_[Snare] = envelope_generators_[7];
|
||
|
||
// Return to ordinary default mode.
|
||
rhythm_mode_enabled_ = false;
|
||
|
||
// 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.
|
||
envelope_generators_[c + 9].set_key_on(true);
|
||
phase_generators_[c + 0].reset();
|
||
phase_generators_[c + 9].reset();
|
||
});
|
||
}
|
||
|
||
// Set default instrument.
|
||
for(int c = 0; c < 9; ++c) {
|
||
install_instrument(c);
|
||
}
|
||
}
|
||
|
||
// MARK: - Machine-facing programmatic input.
|
||
|
||
void OPLL::write_register(uint8_t address, uint8_t value) {
|
||
// The OPLL doesn't have timers or other non-audio functions, so all writes
|
||
// go to the audio queue.
|
||
task_queue_.enqueue([this, address, value] {
|
||
// The first 8 locations are used to define the custom instrument, and have
|
||
// exactly the same format as the patch set arrays at the head of this file.
|
||
if(address < 8) {
|
||
custom_instrument_[address] = value;
|
||
|
||
// Update all channels that refer to instrument 0.
|
||
for(int c = 0; c < 9; ++c) {
|
||
if(!channels_[c].instrument) {
|
||
install_instrument(c);
|
||
}
|
||
}
|
||
|
||
return;
|
||
}
|
||
|
||
// Register 0xe enables or disables rhythm mode and contains the
|
||
// percussion key-on bits.
|
||
if(address == 0xe) {
|
||
const bool old_rhythm_mode = rhythm_mode_enabled_;
|
||
rhythm_mode_enabled_ = value & 0x20;
|
||
if(old_rhythm_mode != rhythm_mode_enabled_) {
|
||
// Change the instlled instruments for channels 6, 7 and 8
|
||
// if this was a transition into or out of rhythm mode.
|
||
install_instrument(6);
|
||
install_instrument(7);
|
||
install_instrument(8);
|
||
}
|
||
rhythm_envelope_generators_[HighHat].set_key_on(value & 0x01);
|
||
rhythm_envelope_generators_[Cymbal].set_key_on(value & 0x02);
|
||
rhythm_envelope_generators_[TomTom].set_key_on(value & 0x04);
|
||
rhythm_envelope_generators_[Snare].set_key_on(value & 0x08);
|
||
if(value & 0x10) {
|
||
rhythm_envelope_generators_[BassCarrier].set_key_on(true);
|
||
} else {
|
||
rhythm_envelope_generators_[BassCarrier].set_key_on(false);
|
||
rhythm_envelope_generators_[BassModulator].set_key_on(false);
|
||
|
||
}
|
||
return;
|
||
}
|
||
|
||
// That leaves only per-channel selections, for which the addressing
|
||
// is completely orthogonal; check that a valid channel is being requested.
|
||
const auto index = address & 0xf;
|
||
if(index > 8) return;
|
||
|
||
switch(address & 0xf0) {
|
||
default: break;
|
||
|
||
// Address 1x sets the low 8 bits of the period for channel x.
|
||
case 0x10:
|
||
channels_[index].period = (channels_[index].period & ~0xff) | value;
|
||
set_channel_period(index);
|
||
return;
|
||
|
||
// Address 2x Sets the octave and a single bit of the frequency, as well
|
||
// as setting key on and sustain mode.
|
||
case 0x20:
|
||
channels_[index].period = (channels_[index].period & 0xff) | ((value & 1) << 8);
|
||
channels_[index].octave = (value >> 1) & 7;
|
||
set_channel_period(index);
|
||
|
||
// In this implementation the first 9 envelope generators are for
|
||
// channel carriers, and their will_attack callback is used to trigger
|
||
// key-on for modulators. But key-off needs to be set to both envelope
|
||
// generators now.
|
||
if(value & 0x10) {
|
||
envelope_generators_[index].set_key_on(true);
|
||
} else {
|
||
envelope_generators_[index + 0].set_key_on(false);
|
||
envelope_generators_[index + 9].set_key_on(false);
|
||
}
|
||
|
||
// Set sustain bit to both the relevant operators.
|
||
channels_[index].use_sustain = value & 0x20;
|
||
set_use_sustain(index);
|
||
return;
|
||
|
||
// Address 3x selects the instrument and attenuation for a channel;
|
||
// in rhythm mode some of the nibbles that ordinarily identify instruments
|
||
// instead nominate additional attenuations. This code reads those back
|
||
// from the stored instrument values.
|
||
case 0x30:
|
||
channels_[index].attenuation = value & 0xf;
|
||
|
||
// Install an instrument only if it's new.
|
||
if(channels_[index].instrument != value >> 4) {
|
||
channels_[index].instrument = value >> 4;
|
||
if(index < 6 || !rhythm_mode_enabled_) {
|
||
install_instrument(index);
|
||
}
|
||
}
|
||
return;
|
||
}
|
||
});
|
||
}
|
||
|
||
void OPLL::set_channel_period(int channel) {
|
||
phase_generators_[channel + 0].set_period(channels_[channel].period, channels_[channel].octave);
|
||
phase_generators_[channel + 9].set_period(channels_[channel].period, channels_[channel].octave);
|
||
|
||
envelope_generators_[channel + 0].set_period(channels_[channel].period, channels_[channel].octave);
|
||
envelope_generators_[channel + 9].set_period(channels_[channel].period, channels_[channel].octave);
|
||
|
||
key_level_scalers_[channel + 0].set_period(channels_[channel].period, channels_[channel].octave);
|
||
key_level_scalers_[channel + 9].set_period(channels_[channel].period, channels_[channel].octave);
|
||
}
|
||
|
||
const uint8_t *OPLL::instrument_definition(int instrument, int channel) {
|
||
// Divert to the appropriate rhythm instrument if in rhythm mode.
|
||
if(channel >= 6 && rhythm_mode_enabled_) {
|
||
return &percussion_patch_set[(channel - 6) * 8];
|
||
}
|
||
|
||
// Instrument 0 is the custom instrument.
|
||
if(!instrument) return custom_instrument_;
|
||
|
||
// Instruments other than 0 are taken from the fixed set.
|
||
const int index = (instrument - 1) * 8;
|
||
return is_vrc7_ ? &vrc7_patch_set[index] : &opll_patch_set[index];
|
||
}
|
||
|
||
void OPLL::install_instrument(int channel) {
|
||
auto &carrier_envelope = envelope_generators_[channel + 0];
|
||
auto &carrier_phase = phase_generators_[channel + 0];
|
||
auto &carrier_scaler = key_level_scalers_[channel + 0];
|
||
|
||
auto &modulator_envelope = envelope_generators_[channel + 9];
|
||
auto &modulator_phase = phase_generators_[channel + 9];
|
||
auto &modulator_scaler = key_level_scalers_[channel + 9];
|
||
|
||
const uint8_t *const instrument = instrument_definition(channels_[channel].instrument, channel);
|
||
|
||
// Bytes 0 (modulator) and 1 (carrier):
|
||
//
|
||
// b0-b3: multiplier;
|
||
// b4: key-scale rate enable;
|
||
// b5: sustain-level enable;
|
||
// b6: vibrato enable;
|
||
// b7: tremolo enable.
|
||
modulator_phase.set_multiple(instrument[0] & 0xf);
|
||
channels_[channel].modulator_key_rate_scale_multiplier = (instrument[0] >> 4) & 1;
|
||
modulator_phase.set_vibrato_enabled(instrument[0] & 0x40);
|
||
modulator_envelope.set_tremolo_enabled(instrument[0] & 0x80);
|
||
|
||
carrier_phase.set_multiple(instrument[1] & 0xf);
|
||
channels_[channel].carrier_key_rate_scale_multiplier = (instrument[1] >> 4) & 1;
|
||
carrier_phase.set_vibrato_enabled(instrument[1] & 0x40);
|
||
carrier_envelope.set_tremolo_enabled(instrument[1] & 0x80);
|
||
|
||
// Pass off bit 5.
|
||
set_use_sustain(channel);
|
||
|
||
// Byte 2:
|
||
//
|
||
// b0–b5: modulator attenuation;
|
||
// b6–b7: modulator key-scale level.
|
||
modulator_scaler.set_key_scaling_level(instrument[3] >> 6);
|
||
channels_[channel].modulator_attenuation = instrument[2] & 0x3f;
|
||
|
||
// Byte 3:
|
||
//
|
||
// b0–b2: modulator feedback level;
|
||
// b3: modulator waveform selection;
|
||
// b4: carrier waveform selection;
|
||
// b5: [unused]
|
||
// b6–b7: carrier key-scale level.
|
||
channels_[channel].modulator_feedback = instrument[3] & 7;
|
||
channels_[channel].modulator_waveform = Waveform((instrument[3] >> 3) & 1);
|
||
channels_[channel].carrier_waveform = Waveform((instrument[3] >> 4) & 1);
|
||
carrier_scaler.set_key_scaling_level(instrument[3] >> 6);
|
||
|
||
// Bytes 4 (modulator) and 5 (carrier):
|
||
//
|
||
// b0–b3: decay rate;
|
||
// b4–b7: attack rate.
|
||
modulator_envelope.set_decay_rate(instrument[4] & 0xf);
|
||
modulator_envelope.set_attack_rate(instrument[4] >> 4);
|
||
carrier_envelope.set_decay_rate(instrument[5] & 0xf);
|
||
carrier_envelope.set_attack_rate(instrument[5] >> 4);
|
||
|
||
// Bytes 6 (modulator) and 7 (carrier):
|
||
//
|
||
// b0–b3: release rate;
|
||
// b4–b7: sustain level.
|
||
modulator_envelope.set_release_rate(instrument[6] & 0xf);
|
||
modulator_envelope.set_sustain_level(instrument[6] >> 4);
|
||
carrier_envelope.set_release_rate(instrument[7] & 0xf);
|
||
carrier_envelope.set_sustain_level(instrument[7] >> 4);
|
||
}
|
||
|
||
void OPLL::set_use_sustain(int channel) {
|
||
const uint8_t *const instrument = instrument_definition(channels_[channel].instrument, channel);
|
||
envelope_generators_[channel + 0].set_use_sustain_level((instrument[1] & 0x20) || channels_[channel].use_sustain);
|
||
envelope_generators_[channel + 9].set_use_sustain_level((instrument[0] & 0x20) || channels_[channel].use_sustain);
|
||
}
|
||
|
||
// MARK: - Output generation.
|
||
|
||
void OPLL::set_sample_volume_range(std::int16_t range) {
|
||
total_volume_ = range;
|
||
}
|
||
|
||
void OPLL::get_samples(std::size_t number_of_samples, std::int16_t *target) {
|
||
// Both the OPLL and the OPL2 divide the input clock by 72 to get the base tick frequency;
|
||
// unlike the OPL2 the OPLL time-divides the output for 'mixing'.
|
||
|
||
const int update_period = 72 / audio_divider_;
|
||
const int channel_output_period = 4 / audio_divider_;
|
||
|
||
// TODO: the conditional below is terrible. Fix.
|
||
while(number_of_samples--) {
|
||
if(!audio_offset_) update_all_channels();
|
||
|
||
*target = output_levels_[audio_offset_ / channel_output_period];
|
||
++target;
|
||
audio_offset_ = (audio_offset_ + 1) % update_period;
|
||
}
|
||
}
|
||
|
||
void OPLL::update_all_channels() {
|
||
oscillator_.update();
|
||
|
||
// Update all phase generators. That's guaranteed.
|
||
for(int c = 0; c < 18; ++c) {
|
||
phase_generators_[c].update(oscillator_);
|
||
}
|
||
|
||
// Update the ADSR envelopes that are guaranteed to be melodic.
|
||
for(int c = 0; c < 6; ++c) {
|
||
envelope_generators_[c + 0].update(oscillator_);
|
||
envelope_generators_[c + 9].update(oscillator_);
|
||
}
|
||
|
||
#define VOLUME(x) int16_t(((x) * total_volume_) >> 12)
|
||
|
||
if(rhythm_mode_enabled_) {
|
||
// Advance the rhythm envelope generators.
|
||
for(int c = 0; c < 6; ++c) {
|
||
rhythm_envelope_generators_[c].update(oscillator_);
|
||
}
|
||
|
||
// Fill in the melodic channels.
|
||
output_levels_[3] = VOLUME(melodic_output(0));
|
||
output_levels_[4] = VOLUME(melodic_output(1));
|
||
output_levels_[5] = VOLUME(melodic_output(2));
|
||
|
||
output_levels_[9] = VOLUME(melodic_output(3));
|
||
output_levels_[10] = VOLUME(melodic_output(4));
|
||
output_levels_[11] = VOLUME(melodic_output(5));
|
||
|
||
// Bass drum, which is a regular FM effect.
|
||
output_levels_[2] = output_levels_[15] = VOLUME(bass_drum());
|
||
oscillator_.update_lfsr();
|
||
|
||
// Tom tom, which is a single operator.
|
||
output_levels_[1] = output_levels_[14] = VOLUME(tom_tom());
|
||
oscillator_.update_lfsr();
|
||
|
||
// Snare.
|
||
output_levels_[6] = output_levels_[16] = VOLUME(snare_drum());
|
||
oscillator_.update_lfsr();
|
||
|
||
// Cymbal.
|
||
output_levels_[7] = output_levels_[17] = VOLUME(cymbal());
|
||
oscillator_.update_lfsr();
|
||
|
||
// High-hat.
|
||
output_levels_[0] = output_levels_[13] = VOLUME(high_hat());
|
||
oscillator_.update_lfsr();
|
||
|
||
// Unutilised slots.
|
||
output_levels_[8] = output_levels_[12] = 0;
|
||
oscillator_.update_lfsr();
|
||
} else {
|
||
for(int c = 6; c < 9; ++c) {
|
||
envelope_generators_[c + 0].update(oscillator_);
|
||
envelope_generators_[c + 9].update(oscillator_);
|
||
}
|
||
|
||
// All melodic. Fairly easy.
|
||
output_levels_[0] = output_levels_[1] = output_levels_[2] =
|
||
output_levels_[6] = output_levels_[7] = output_levels_[8] =
|
||
output_levels_[12] = output_levels_[13] = output_levels_[14] = 0;
|
||
|
||
output_levels_[3] = VOLUME(melodic_output(0));
|
||
output_levels_[4] = VOLUME(melodic_output(1));
|
||
output_levels_[5] = VOLUME(melodic_output(2));
|
||
|
||
output_levels_[9] = VOLUME(melodic_output(3));
|
||
output_levels_[10] = VOLUME(melodic_output(4));
|
||
output_levels_[11] = VOLUME(melodic_output(5));
|
||
|
||
output_levels_[15] = VOLUME(melodic_output(6));
|
||
output_levels_[16] = VOLUME(melodic_output(7));
|
||
output_levels_[17] = VOLUME(melodic_output(8));
|
||
}
|
||
|
||
#undef VOLUME
|
||
|
||
// TODO: batch updates of the LFSR.
|
||
}
|
||
|
||
// 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() + 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());
|
||
modulation += envelope_generators_[channel + 9].attenuation() + (channels_[channel].modulator_attenuation << 5) + key_level_scalers_[channel + 9].attenuation();
|
||
|
||
// Apply feedback, if any.
|
||
phase_generators_[channel + 9].apply_feedback(channels_[channel].modulator_output, modulation, channels_[channel].modulator_feedback);
|
||
channels_[channel].modulator_output = modulation;
|
||
|
||
return carrier.level();
|
||
}
|
||
|
||
int OPLL::bass_drum() {
|
||
// Use modulator 6 and carrier 6, attenuated as per the bass-specific envelope generators and the attenuation level for channel 6.
|
||
auto modulation = WaveformGenerator<period_precision>::wave(Waveform::Sine, phase_generators_[6 + 9].phase());
|
||
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() + ATTENUATION(channels_[6].attenuation);
|
||
return carrier.level();
|
||
}
|
||
|
||
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 += ATTENUATION(channels_[8].instrument);
|
||
return tom_tom.level();
|
||
}
|
||
|
||
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 += ATTENUATION(channels_[7].attenuation);
|
||
return snare.level();
|
||
}
|
||
|
||
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 += ATTENUATION(channels_[8].attenuation);
|
||
return cymbal.level();
|
||
}
|
||
|
||
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 += ATTENUATION(channels_[7].instrument);
|
||
return high_hat.level();
|
||
}
|
||
|
||
#undef ATTENUATION
|