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141 lines
3.3 KiB
C++
141 lines
3.3 KiB
C++
#pragma once
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#include "stdafx.h"
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#include "Snapshotable.h"
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#include "EmulationSettings.h"
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#include "APU.h"
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#include "BaseFdsChannel.h"
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#include "ModChannel.h"
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#include <algorithm>
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#include "BaseExpansionAudio.h"
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class FdsAudio : public BaseExpansionAudio
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{
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private:
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const uint32_t WaveVolumeTable[4] = { 36, 24, 17, 14 };
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//Register values
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uint8_t _waveTable[64];
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bool _waveWriteEnabled = false;
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BaseFdsChannel _volume;
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ModChannel _mod;
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bool _disableEnvelopes = false;
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bool _haltWaveform = false;
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uint8_t _masterVolume = 0;
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//Internal values
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uint16_t _waveOverflowCounter = 0;
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int32_t _wavePitch = 0;
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uint8_t _wavePosition = 0;
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uint8_t _lastOutput = 0;
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protected:
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void StreamState(bool saving) override
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{
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BaseExpansionAudio::StreamState(saving);
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ArrayInfo<uint8_t> waveTable = { _waveTable, 64 };
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SnapshotInfo volume{ &_volume };
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SnapshotInfo mod{ &_mod };
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Stream(volume, mod, _waveWriteEnabled, _disableEnvelopes, _haltWaveform, _masterVolume, _waveOverflowCounter, _wavePitch, _wavePosition, _lastOutput, waveTable);
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}
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void ClockAudio() override
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{
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//"The envelopes are not ticked while the waveform is halted."
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_volume.TickEnvelope(_disableEnvelopes || _haltWaveform);
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_mod.TickEnvelope(_disableEnvelopes || _haltWaveform);
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if(_mod.IsEnabled()) {
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if(_mod.TickModulator()) {
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//Modulator was ticked, update wave pitch
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_wavePitch = _mod.GetWavePitch(_volume.GetFrequency());
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}
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} else {
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_wavePitch = 0;
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}
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if(_haltWaveform) {
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//"The high bit of this register halts the waveform and resets its phase to 0. Note that if halted it will output the constant value at $4040"
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//"writes to the volume register $4080 or master volume $4089 will affect the output."
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_wavePosition = 0;
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}
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int32_t freq = _volume.GetFrequency() + _wavePitch;
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if(freq > 0 && !_waveWriteEnabled) {
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_waveOverflowCounter += freq;
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if(_waveOverflowCounter < freq) {
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//Overflow, tick
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uint32_t level = std::min((int)_volume.GetGain(), 32) * WaveVolumeTable[_masterVolume];
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uint8_t outputLevel = (_waveTable[_wavePosition] * level) / 1152;
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APU::AddExpansionAudioDelta(AudioChannel::FDS, outputLevel - _lastOutput);
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_lastOutput = outputLevel;
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_wavePosition = (_wavePosition + 1) & 0x3F;
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}
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}
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}
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public:
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uint8_t ReadRegister(uint16_t addr)
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{
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if(addr <= 0x407F) {
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return 0x40 | _waveTable[addr & 0x3F];
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} else {
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switch(addr) {
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case 0x4090: return 0x40 | _volume.GetGain();
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case 0x4092: return 0x40 | _mod.GetGain();
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}
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}
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return MemoryManager::GetOpenBus();
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}
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void WriteRegister(uint16_t addr, uint8_t value)
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{
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if(addr <= 0x407F) {
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if(_waveWriteEnabled) {
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_waveTable[addr & 0x3F] = value & 0x3F;
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}
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} else {
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switch(addr) {
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case 0x4080:
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case 0x4082:
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_volume.WriteReg(addr, value);
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break;
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case 0x4083:
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_disableEnvelopes = (value & 0x40) == 0x40;
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_haltWaveform = (value & 0x80) == 0x80;
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_volume.WriteReg(addr, value);
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break;
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case 0x4084:
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case 0x4085:
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case 0x4086:
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case 0x4087:
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_mod.WriteReg(addr, value);
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break;
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case 0x4088:
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_mod.WriteModTable(value);
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break;
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case 0x4089:
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_masterVolume = value & 0x03;
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_waveWriteEnabled = (value & 0x80) == 0x80;
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break;
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case 0x408A:
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_volume.SetMasterEnvelopeSpeed(value);
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_mod.SetMasterEnvelopeSpeed(value);
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break;
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}
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}
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}
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}; |