89 lines
2.3 KiB
C++
89 lines
2.3 KiB
C++
/*
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Peacock-8 VA polysynth
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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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#include "ic29.hpp"
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Synth s;
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Synth::Synth() {
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d_debug("initialising synth\n");
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envAtk = 0x007f;
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envDcy = envRls = 0xfe90;
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envStn = 0x1fff;
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}
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void Synth::run() {
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// handle a "loop" worth of envelopes, pitch calculations, etc
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// callled once every 4.3ms block of samples
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for (uint8_t i = 0; i < NUM_VOICES; i++) {
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s.voices[i].env.run();
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}
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}
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void Synth::voiceOn(uint8_t voice, uint8_t note) {
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// enable synth voice, start it all running
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voice &= 0x7f;
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s.voices[voice].env.on();
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// FIXME determine if we need to reset the counter
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s.voices[voice].note = note;
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}
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void Synth::voiceOff(uint8_t voice) {
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// enable synth voice, start it all running
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voice &= 0x7f;
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s.voices[voice].env.off();
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}
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Envelope::Envelope() {
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level = 0;
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phase = ENV_IDLE;
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}
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void Envelope::run() {
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switch (phase) {
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case ENV_ATK:
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level += s.envAtk;
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if (level > 0x3fff) {
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level = 0x3fff;
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phase = ENV_DCY;
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}
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break;
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case ENV_DCY:
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if (level > s.envStn) {
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level -= s.envStn;
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level = (level * s.envDcy) >> 16;
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level += s.envStn;
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} else {
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level = s.envStn;
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}
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break;
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case ENV_RLS:
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level = (level * s.envRls) >> 16;
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break;
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case ENV_IDLE:
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default:
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break;
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}
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}
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Voice::Voice() {
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}
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extern Synth s; |