mirror of
https://github.com/QB64-Phoenix-Edition/QB64pe.git
synced 2024-09-20 09:04:43 +00:00
205 lines
6.3 KiB
C++
205 lines
6.3 KiB
C++
/*
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The Opal OPL3 emulator (header).
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Note: this is not a complete emulator, just enough for Reality Adlib Tracker tunes.
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Missing features compared to a real OPL3:
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- Timers/interrupts
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- OPL3 enable bit (it defaults to always on)
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- CSW mode
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- Test register
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- Percussion mode
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*/
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// This is the Opal OPL3 emulator from Reality Adlib Tracker v2.0a (http://www.3eality.com/productions/reality-adlib-tracker).
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// It was released by Shayde/Reality into the public domain.
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// Minor modifications to silence some warnings and fix a bug in the envelope generator have been applied.
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// Additional fixes by JP Cimalando.
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// Soft panning support by Wohlstand.
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#pragma once
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#include <cstdint>
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//==================================================================================================
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// Opal class.
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//==================================================================================================
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class Opal {
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class Channel;
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// Various constants
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enum {
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OPL3SampleRate = 49716,
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NumChannels = 18,
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NumOperators = 36,
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EnvOff = -1,
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EnvAtt,
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EnvDec,
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EnvSus,
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EnvRel
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};
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// A single FM operator
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class Operator {
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public:
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Operator();
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void SetMaster(Opal *opal) { Master = opal; }
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void SetChannel(Channel *chan) { Chan = chan; }
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int16_t Output(uint16_t keyscalenum, uint32_t phase_step, int16_t vibrato, int16_t mod = 0, int16_t fbshift = 0);
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void SetKeyOn(bool on);
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void SetTremoloEnable(bool on);
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void SetVibratoEnable(bool on);
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void SetSustainMode(bool on);
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void SetEnvelopeScaling(bool on);
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void SetFrequencyMultiplier(uint16_t scale);
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void SetKeyScale(uint16_t scale);
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void SetOutputLevel(uint16_t level);
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void SetAttackRate(uint16_t rate);
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void SetDecayRate(uint16_t rate);
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void SetSustainLevel(uint16_t level);
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void SetReleaseRate(uint16_t rate);
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void SetWaveform(uint16_t wave);
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void ComputeRates();
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void ComputeKeyScaleLevel();
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protected:
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Opal *Master; // Master object
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Channel *Chan; // Owning channel
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uint32_t Phase; // The current offset in the selected waveform
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uint16_t Waveform; // The waveform id this operator is using
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uint16_t FreqMultTimes2; // Frequency multiplier * 2
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int EnvelopeStage; // Which stage the envelope is at (see Env* enums above)
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int16_t EnvelopeLevel; // 0 - $1FF, 0 being the loudest
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uint16_t OutputLevel; // 0 - $FF
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uint16_t AttackRate;
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uint16_t DecayRate;
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uint16_t SustainLevel;
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uint16_t ReleaseRate;
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uint16_t AttackShift;
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uint16_t AttackMask;
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uint16_t AttackAdd;
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const uint16_t *AttackTab;
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uint16_t DecayShift;
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uint16_t DecayMask;
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uint16_t DecayAdd;
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const uint16_t *DecayTab;
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uint16_t ReleaseShift;
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uint16_t ReleaseMask;
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uint16_t ReleaseAdd;
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const uint16_t *ReleaseTab;
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uint16_t KeyScaleShift;
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uint16_t KeyScaleLevel;
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int16_t Out[2];
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bool KeyOn;
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bool KeyScaleRate; // Affects envelope rate scaling
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bool SustainMode; // Whether to sustain during the sustain phase, or release instead
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bool TremoloEnable;
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bool VibratoEnable;
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};
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// A single channel, which can contain two or more operators
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class Channel {
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public:
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Channel();
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void SetMaster(Opal *opal) { Master = opal; }
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void SetOperators(Operator *a, Operator *b, Operator *c, Operator *d) {
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Op[0] = a;
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Op[1] = b;
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Op[2] = c;
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Op[3] = d;
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if (a)
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a->SetChannel(this);
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if (b)
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b->SetChannel(this);
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if (c)
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c->SetChannel(this);
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if (d)
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d->SetChannel(this);
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}
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void Output(int16_t &left, int16_t &right);
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void SetEnable(bool on) { Enable = on; }
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void SetChannelPair(Channel *pair) { ChannelPair = pair; }
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void SetFrequencyLow(uint16_t freq);
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void SetFrequencyHigh(uint16_t freq);
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void SetKeyOn(bool on);
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void SetOctave(uint16_t oct);
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void SetLeftEnable(bool on);
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void SetRightEnable(bool on);
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void SetPan(uint8_t pan);
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void SetFeedback(uint16_t val);
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void SetModulationType(uint16_t type);
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uint16_t GetFreq() const { return Freq; }
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uint16_t GetOctave() const { return Octave; }
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uint16_t GetKeyScaleNumber() const { return KeyScaleNumber; }
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uint16_t GetModulationType() const { return ModulationType; }
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Channel *GetChannelPair() const { return ChannelPair; }
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void ComputeKeyScaleNumber();
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protected:
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void ComputePhaseStep();
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Operator *Op[4];
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Opal *Master; // Master object
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uint16_t Freq; // Frequency; actually it's a phase stepping value
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uint16_t Octave; // Also known as "block" in Yamaha parlance
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uint32_t PhaseStep;
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uint16_t KeyScaleNumber;
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uint16_t FeedbackShift;
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uint16_t ModulationType;
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Channel *ChannelPair;
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bool Enable;
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bool LeftEnable, RightEnable;
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uint16_t LeftPan, RightPan;
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};
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public:
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Opal(int sample_rate);
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Opal(const Opal &) = delete;
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Opal(Opal &&) = delete;
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~Opal();
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void SetSampleRate(int sample_rate);
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void Port(uint16_t reg_num, uint8_t val);
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void Pan(uint16_t reg_num, uint8_t pan);
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void Sample(int16_t *left, int16_t *right);
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protected:
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void Init(int sample_rate);
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void Output(int16_t &left, int16_t &right);
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int32_t SampleRate;
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int32_t SampleAccum;
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int16_t LastOutput[2], CurrOutput[2];
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Channel Chan[NumChannels];
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Operator Op[NumOperators];
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// uint16_t ExpTable[256];
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// uint16_t LogSinTable[256];
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uint16_t Clock;
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uint16_t TremoloClock;
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uint16_t TremoloLevel;
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uint16_t VibratoTick;
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uint16_t VibratoClock;
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bool NoteSel;
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bool TremoloDepth;
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bool VibratoDepth;
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static const uint16_t RateTables[4][8];
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static const uint16_t ExpTable[256];
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static const uint16_t LogSinTable[256];
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static const uint16_t PanLawTable[128];
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};
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