95 lines
3.3 KiB
C++
95 lines
3.3 KiB
C++
/*
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Peacock-8 VA polysynth
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Copyright 2025 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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#include "module.hpp"
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#include <stdio.h>
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#include "tables.hpp"
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Module::Module() {
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}
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void Module::run(Voice* voice) {
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// run updates for module board
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// FIXME break these out to the patch setter
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a = attackTable[patchRam.env_a]; // attack time coeff looked up in table
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d = decayTable[patchRam.env_d]; // decay time coeff looked up in table
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r = decayTable[patchRam.env_r]; // release time coeff looked up in table
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s = patchRam.env_s << 7; // scale 0x00-0x7f to 0x0000-0x3f80
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square = (patchRam.switch1 & 0x08) ? 0.63 : 0;
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saw = (patchRam.switch1 & 0x10) ? 0.8 : 0;
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sub = patchRam.sub / 127.0f;
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lfoPhase += lfoRateTable[patchRam.lfoRate];
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if (lfoPhase & 0x4000)
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lfo = 0x1fff - (lfoPhase & 0x3fff);
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else
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lfo = (lfoPhase & 0x3fff) - 0x1fff;
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pw = 0.5- ((0x2000 + lfo) * patchRam.pwmLfo) / (32768.0f*128);
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// printf("%5d\n", (lfo * lfoDepthTable[patchRam.vcoLfo])>>8);
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int16_t vcf = (patchRam.vcfEnv << 7) * ((patchRam.switch2 & 0x02) ? -1 : 1);
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int16_t pitchBase = 0x1818;
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pitchBase += (lfo * lfoDepthTable[patchRam.vcoLfo]) >> 9;
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for (uint32_t i = 0; i < NUM_VOICES; i++) {
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// maybe move all this into voice.cpp FIXME
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Voice* v = &voice[i];
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switch (v->envPhase) {
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case 0: // release phase FIXME use an enum I guess
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v->env = (v->env * r) >> 16; // "RC" decay to zero
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break;
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case 1: // attack phase
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v->env += a; // linear attack to 0x3fff
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break;
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case 2:
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v->env = (((v->env - s) * d) >> 16) + s;
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break;
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}
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if (v->env > 0x3fff) {
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v->env = 0x3fff;
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v->envPhase = 2; // flip to decay
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}
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// pitch
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int16_t pitch = pitchBase + (v->note << 8);
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int16_t semi = pitch >> 8;
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float frac = (pitch & 0xff) / 256.0;
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float p1 = pitchTable[semi], p2 = pitchTable[semi + 1];
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int16_t px = ((p2 - p1) * frac + p1);
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v->omega = px / 192000.0f; // fixme use proper scaler
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// per voice we need to calculate the key follow amount and envelope amount
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v->vcfCut = (patchRam.vcfFreq << 7) + ((vcf * v->env) >> 16);
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v->vcfCut += (int)(v->note * (patchRam.vcfKey << 1) * 0.375);
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if (v->vcfCut > 0x3fff) v->vcfCut = 0x3fff;
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if (v->vcfCut < 0) v->vcfCut = 0;
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v->vcaEnv = (patchRam.switch2 & 0x04) ? (v->envPhase ? 0x3fff : 0) : v->env;
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}
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}
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