142 lines
4.1 KiB
C++
142 lines
4.1 KiB
C++
/*
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tonewheel organ plugin
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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 "assigner.hpp"
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#define DEBUG
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void Assigner::dumpTables() {
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#ifdef DEBUG
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printf("table state is:\n");
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for (uint8_t i = 0; i < NUM_VOICES; i++) {
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uint8_t e = voiceTbl[i];
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uint8_t a = noteTbl[e];
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printf("%2d=%3d%c ", e, a & 0x7f, (a & 0x80) ? '^' : 'v');
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}
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printf("\n");
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#endif
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}
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Assigner::Assigner() {
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d_debug("assigner constructor");
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// set up the assigner tables
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for (uint8_t i = 0; i < NUM_VOICES; i++) {
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voiceTbl[i] = i;
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noteTbl[i] = 0x80;
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}
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}
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void Assigner::handleMidi(MidiEvent *ev) {
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uint8_t status = ev->data[0];
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switch (status & 0xf0) {
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case 0x80:
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noteOff(ev->data[1]);
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dumpTables();
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break;
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case 0x90:
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// dumpTables();
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noteOn(ev->data[1]);
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dumpTables();
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break;
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case 0xb0:
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switch (ev->data[1]) {
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// maybe handle the following
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// CC 1 - modwheel
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// CC 64 - sustain
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default:
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break;
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}
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break; // nothing to do here except in special cases where we don't expect the host to pass on controls
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case 0xc0: // program change
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break;
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case 0xe0: // pitch bend;
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break;
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case 0xf0: // sysex
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break;
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default:
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d_debug("unhandled MIDI event, status %02x value %02x\n", ev->data[0], ev->data[1]);
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break;
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}
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}
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void Assigner::noteOff(uint8_t note) {
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d_debug("note off %3d", note);
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uint8_t i, v;
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// scan for note in table
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for (i = 0; i < NUM_VOICES; i++) {
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if ((noteTbl[voiceTbl[i]] & 0x7f) == note) break;
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}
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if (i == NUM_VOICES) return; // got note off for note that isn't in the table
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// get the voice at this slot
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// then move the rest down and place this at the end
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// and mark the note for this voice as "off" by setting bit 7
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v = voiceTbl[i];
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memmove(voiceTbl + i, voiceTbl + i + 1, NUM_VOICES - i - 1);
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voiceTbl[NUM_VOICES - 1] = v;
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noteTbl[v] |= 0x80;
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}
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void Assigner::noteOn(uint8_t note) {
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d_debug("note on %3d", note);
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int8_t i, a, v;
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// don't even attempt to steal voices
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// by overwriting the last voice in the table
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// we could actually do voice stealing
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if ((noteTbl[voiceTbl[NUM_VOICES - 1]] & 0x80) == 0x00) {
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d_debug("note table full");
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return;
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}
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// loop around the voices
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for (i = NUM_VOICES - 1; i >= 0; i--) {
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v = voiceTbl[i];
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a = noteTbl[v];
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// if this note is playing we've gone too far
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// we need to back up a slot and consider it for use
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if ((a & 0x80) == 0) {
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i++;
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// shunt them all up to the end
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v = voiceTbl[i];
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memmove(voiceTbl + 1, voiceTbl, i);
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voiceTbl[0] = v;
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break; // note is already playing in table
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}
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if ((a & 0x7f) == note) {
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memmove(voiceTbl + 1, voiceTbl, i);
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voiceTbl[0] = v;
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a &= 0x7f;
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break;
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}
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}
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noteTbl[v] = note;
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// limit lowest note to C2 and highest note to C7
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while(note>96) note -= 12;
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while(note<36) note += 12;
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d_debug("send voice on note %3d to voice %d", note, v);
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}
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