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