363 lines
12 KiB
C
363 lines
12 KiB
C
/* Copyright 2016 Jack Humbert
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* Copyright 2020 JohSchneider
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "voices.h"
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#include "audio.h"
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#include <stdlib.h>
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uint8_t note_timbre = TIMBRE_DEFAULT;
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bool glissando = false;
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bool vibrato = false;
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float vibrato_strength = 0.5;
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float vibrato_rate = 0.125;
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uint16_t voices_timer = 0;
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#ifdef AUDIO_VOICE_DEFAULT
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voice_type voice = AUDIO_VOICE_DEFAULT;
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#else
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voice_type voice = default_voice;
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#endif
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void set_voice(voice_type v) {
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voice = v;
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}
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void voice_iterate(void) {
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voice = (voice + 1) % number_of_voices;
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}
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void voice_deiterate(void) {
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voice = (voice - 1 + number_of_voices) % number_of_voices;
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}
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#ifdef AUDIO_VOICES
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float mod(float a, int b) {
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float r = fmod(a, b);
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return r < 0 ? r + b : r;
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}
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// Effect: 'vibrate' a given target frequency slightly above/below its initial value
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float voice_add_vibrato(float average_freq) {
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float vibrato_counter = mod(timer_read() / (100 * vibrato_rate), VIBRATO_LUT_LENGTH);
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return average_freq * pow(vibrato_lut[(int)vibrato_counter], vibrato_strength);
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}
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// Effect: 'slides' the 'frequency' from the starting-point, to the target frequency
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float voice_add_glissando(float from_freq, float to_freq) {
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if (to_freq != 0 && from_freq < to_freq && from_freq < to_freq * pow(2, -440 / to_freq / 12 / 2)) {
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return from_freq * pow(2, 440 / from_freq / 12 / 2);
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} else if (to_freq != 0 && from_freq > to_freq && from_freq > to_freq * pow(2, 440 / to_freq / 12 / 2)) {
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return from_freq * pow(2, -440 / from_freq / 12 / 2);
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} else {
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return to_freq;
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}
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}
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#endif
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float voice_envelope(float frequency) {
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// envelope_index ranges from 0 to 0xFFFF, which is preserved at 880.0 Hz
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// __attribute__((unused)) uint16_t compensated_index = (uint16_t)((float)envelope_index * (880.0 / frequency));
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#ifdef AUDIO_VOICES
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uint16_t envelope_index = timer_elapsed(voices_timer); // TODO: multiply in some factor?
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uint16_t compensated_index = envelope_index / 100; // TODO: correct factor would be?
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#endif
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switch (voice) {
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case default_voice:
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glissando = false;
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// note_timbre = TIMBRE_50; //Note: leave the user the possibility to adjust the timbre with 'audio_set_timbre'
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break;
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#ifdef AUDIO_VOICES
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case vibrating:
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glissando = false;
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vibrato = true;
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break;
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case something:
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glissando = false;
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switch (compensated_index) {
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case 0 ... 9:
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note_timbre = TIMBRE_12;
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break;
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case 10 ... 19:
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note_timbre = TIMBRE_25;
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break;
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case 20 ... 200:
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note_timbre = 12 + 12;
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break;
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default:
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note_timbre = 12;
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break;
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}
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break;
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case drums:
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glissando = false;
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// switch (compensated_index) {
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// case 0 ... 10:
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// note_timbre = 50;
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// break;
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// case 11 ... 20:
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// note_timbre = 50 * (21 - compensated_index) / 10;
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// break;
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// default:
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// note_timbre = 0;
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// break;
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// }
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// frequency = (rand() % (int)(frequency * 1.2 - frequency)) + (frequency * 0.8);
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if (frequency < 80.0) {
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} else if (frequency < 160.0) {
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// Bass drum: 60 - 100 Hz
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frequency = (rand() % (int)(40)) + 60;
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switch (envelope_index) {
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case 0 ... 10:
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note_timbre = 50;
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break;
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case 11 ... 20:
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note_timbre = 50 * (21 - envelope_index) / 10;
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break;
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default:
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note_timbre = 0;
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break;
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}
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} else if (frequency < 320.0) {
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// Snare drum: 1 - 2 KHz
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frequency = (rand() % (int)(1000)) + 1000;
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switch (envelope_index) {
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case 0 ... 5:
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note_timbre = 50;
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break;
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case 6 ... 20:
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note_timbre = 50 * (21 - envelope_index) / 15;
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break;
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default:
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note_timbre = 0;
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break;
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}
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} else if (frequency < 640.0) {
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// Closed Hi-hat: 3 - 5 KHz
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frequency = (rand() % (int)(2000)) + 3000;
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switch (envelope_index) {
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case 0 ... 15:
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note_timbre = 50;
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break;
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case 16 ... 20:
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note_timbre = 50 * (21 - envelope_index) / 5;
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break;
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default:
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note_timbre = 0;
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break;
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}
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} else if (frequency < 1280.0) {
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// Open Hi-hat: 3 - 5 KHz
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frequency = (rand() % (int)(2000)) + 3000;
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switch (envelope_index) {
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case 0 ... 35:
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note_timbre = 50;
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break;
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case 36 ... 50:
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note_timbre = 50 * (51 - envelope_index) / 15;
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break;
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default:
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note_timbre = 0;
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break;
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}
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}
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break;
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case butts_fader:
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glissando = true;
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switch (compensated_index) {
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case 0 ... 9:
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frequency = frequency / 4;
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note_timbre = TIMBRE_12;
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break;
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case 10 ... 19:
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frequency = frequency / 2;
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note_timbre = TIMBRE_12;
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break;
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case 20 ... 200:
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note_timbre = 12 - (uint8_t)(pow(((float)compensated_index - 20) / (200 - 20), 2) * 12.5);
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break;
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default:
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note_timbre = 0;
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break;
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}
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break;
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// case octave_crunch:
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// switch (compensated_index) {
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// case 0 ... 9:
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// case 20 ... 24:
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// case 30 ... 32:
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// frequency = frequency / 2;
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// note_timbre = TIMBRE_12;
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// break;
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// case 10 ... 19:
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// case 25 ... 29:
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// case 33 ... 35:
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// frequency = frequency * 2;
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// note_timbre = TIMBRE_12;
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// break;
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// default:
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// note_timbre = TIMBRE_12;
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// break;
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// }
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// break;
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case duty_osc:
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// This slows the loop down a substantial amount, so higher notes may freeze
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glissando = true;
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switch (compensated_index) {
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default:
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# define OCS_SPEED 10
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# define OCS_AMP .25
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// sine wave is slow
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// note_timbre = (sin((float)compensated_index/10000*OCS_SPEED) * OCS_AMP / 2) + .5;
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// triangle wave is a bit faster
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note_timbre = (uint8_t)abs((compensated_index * OCS_SPEED % 3000) - 1500) * (OCS_AMP / 1500) + (1 - OCS_AMP) / 2;
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break;
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}
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break;
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case duty_octave_down:
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glissando = true;
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note_timbre = (uint8_t)(100 * (envelope_index % 2) * .125 + .375 * 2);
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if ((envelope_index % 4) == 0) note_timbre = 50;
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if ((envelope_index % 8) == 0) note_timbre = 0;
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break;
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case delayed_vibrato:
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glissando = true;
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note_timbre = TIMBRE_50;
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# define VOICE_VIBRATO_DELAY 150
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# define VOICE_VIBRATO_SPEED 50
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switch (compensated_index) {
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case 0 ... VOICE_VIBRATO_DELAY:
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break;
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default:
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// TODO: merge/replace with voice_add_vibrato above
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frequency = frequency * vibrato_lut[(int)fmod((((float)compensated_index - (VOICE_VIBRATO_DELAY + 1)) / 1000 * VOICE_VIBRATO_SPEED), VIBRATO_LUT_LENGTH)];
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break;
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}
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break;
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// case delayed_vibrato_octave:
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// if ((envelope_index % 2) == 1) {
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// note_timbre = 55;
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// } else {
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// note_timbre = 45;
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// }
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// #define VOICE_VIBRATO_DELAY 150
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// #define VOICE_VIBRATO_SPEED 50
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// switch (compensated_index) {
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// case 0 ... VOICE_VIBRATO_DELAY:
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// break;
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// default:
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// frequency = frequency * VIBRATO_LUT[(int)fmod((((float)compensated_index - (VOICE_VIBRATO_DELAY + 1))/1000*VOICE_VIBRATO_SPEED), VIBRATO_LUT_LENGTH)];
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// break;
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// }
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// break;
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// case duty_fifth_down:
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// note_timbre = TIMBRE_50;
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// if ((envelope_index % 3) == 0)
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// note_timbre = TIMBRE_75;
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// break;
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// case duty_fourth_down:
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// note_timbre = 0;
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// if ((envelope_index % 12) == 0)
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// note_timbre = TIMBRE_75;
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// if (((envelope_index % 12) % 4) != 1)
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// note_timbre = TIMBRE_75;
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// break;
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// case duty_third_down:
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// note_timbre = TIMBRE_50;
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// if ((envelope_index % 5) == 0)
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// note_timbre = TIMBRE_75;
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// break;
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// case duty_fifth_third_down:
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// note_timbre = TIMBRE_50;
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// if ((envelope_index % 5) == 0)
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// note_timbre = TIMBRE_75;
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// if ((envelope_index % 3) == 0)
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// note_timbre = TIMBRE_25;
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// break;
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#endif // AUDIO_VOICES
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default:
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break;
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}
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#ifdef AUDIO_VOICES
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if (vibrato && (vibrato_strength > 0)) {
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frequency = voice_add_vibrato(frequency);
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}
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if (glissando) {
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// TODO: where to keep track of the start-frequency?
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// frequency = voice_add_glissando(??, frequency);
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}
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#endif // AUDIO_VOICES
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return frequency;
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}
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// Vibrato functions
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void voice_set_vibrato_rate(float rate) {
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vibrato_rate = rate;
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}
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void voice_increase_vibrato_rate(float change) {
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vibrato_rate *= change;
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}
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void voice_decrease_vibrato_rate(float change) {
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vibrato_rate /= change;
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}
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void voice_set_vibrato_strength(float strength) {
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vibrato_strength = strength;
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}
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void voice_increase_vibrato_strength(float change) {
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vibrato_strength *= change;
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}
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void voice_decrease_vibrato_strength(float change) {
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vibrato_strength /= change;
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}
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// Timbre functions
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void voice_set_timbre(uint8_t timbre) {
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if ((timbre > 0) && (timbre < 100)) {
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note_timbre = timbre;
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}
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}
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uint8_t voice_get_timbre(void) {
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return note_timbre;
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}
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