140 lines
4.1 KiB
C++
140 lines
4.1 KiB
C++
/*
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Chassis polysynth framework
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Copyright 2024 Gordon JC Pearce <gordonjcp@gjcp.net>
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#pragma once
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#include <cstdint>
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// uint16_t attack_table[128];
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// uint16_t decay_table[128];
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class Synth;
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class Voice {
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public:
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uint8_t note = 60; // per-voice note, set to middle C at 02b1h
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void on(uint32_t key, bool reset);
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void off();
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bool isFree();
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void run(Synth &s, float *buffer, uint32_t samples);
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void envelope(Synth &s);
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void calcPitch(Synth &s);
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void calcFilter(Synth &s);
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uint16_t ff71 = 0; // stores pitch + fraction
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float omega;
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uint16_t vcfenv;
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private:
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enum { ATTACK,
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DECAY,
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SUSTAIN,
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RELEASE } envState = RELEASE;
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enum { K_OFF,
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K_WAIT,
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K_ON,
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K_SUSTAIN } keyState = K_OFF;
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bool ff00 = 0; // reset DCO clock flag
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bool ff07 = 0; // set to indicate attack phase
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bool ff08 = 0; // set to indicate decay/sustain phase
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bool ff10 = 0; // note on bit
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bool ff11 = 0; // drives the "gate" signal for VCA
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uint16_t ff27 = 0; // envelope for voice
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bool ff33 = 0; // releasing flag
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uint16_t env;
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float phase = 0, subosc = 1;
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// float env, target;
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float delay;
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uint8_t pulseStage = 0;
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float lastpw = 0;
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float vr58c106 = 0;
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float b1, b2, b3, b4;
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};
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class Synth {
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public:
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Voice voice[8];
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float lfo = 0, lfosw = 0.01;
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float lastpw = 0;
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uint32_t blockLeft;
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uint32_t framesLeft = 0;
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bool keyon;
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uint8_t ff63 = 0;
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// RAM from ff00h to ffffh is cleared to zero
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// this is in the startup routine at 0280h
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uint8_t ff1e = 0;
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uint8_t ff34 = 0;
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uint8_t ff4a = 0; // LFO flags
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uint16_t ff4d = 0; // LFO output value
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uint16_t ff4f = 0; // computed PWM LFO
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uint16_t ff51 = 0; // computed pitch LFO
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uint16_t ff53 = 0; // computed VCF LFO
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uint16_t ff56 = 0; // LFO Delay envelope
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uint16_t ff5a = 0; // LFO Delay holdoff
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uint8_t ff64 = 0; // LFO mod sens amount
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uint16_t ff65 = 0; // computed VCF bend amount
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uint8_t ff6a = 0;
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uint8_t ff6b = 0;
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uint8_t ff6e = 0; // fractional pitch temp
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uint16_t ff6f = 0; // computed pitch amount
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// uint16_t ff71 = 0; // unsure, to do with pitch
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// okay, not the greatest, this right here
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// this struct contains the bytes that make up a Juno 106 patch in
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// sysex order, exactly as they'd be transmitted or received by a
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// real one.
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// the horrifying implication here is that we can just shunt this
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// around and memcpy() values from sysex on top of it
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// this is set to a "sensible" patch
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// the comments indicate what the defaults are set to
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// in the routine at 02c2h, in case they're important
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struct {
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uint8_t lfoRate = 57; // lookup value defaults to 0x0200
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uint8_t lfoDelay = 45;
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uint8_t vcoLfo = 0;
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uint8_t pwmLfo = 55;
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uint8_t noise = 0;
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uint8_t vcfFreq = 85; // 0x3f80
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uint8_t vcfReso = 0;
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uint8_t vcfEnv = 0;
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uint8_t vcfLfo = 0;
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uint8_t vcfKey = 108;
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uint8_t vca = 52;
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uint8_t env_a = 59;
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uint8_t env_d = 32;
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uint8_t env_s = 86; // 0x3f80
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uint8_t env_r = 40;
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uint8_t sub = 0;
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uint8_t switch1 = 26;
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uint8_t switch2 = 24;
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} patchRam;
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float pitchCV[104];
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void runLFO();
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void lfoDelay();
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};
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