106 lines
3.3 KiB
C
106 lines
3.3 KiB
C
#include "voices.h"
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// these are imported from audio.c
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extern uint16_t envelope_index;
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extern float note_timbre;
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extern float polyphony_rate;
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voice_type voice = duty_osc;
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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() {
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voice = (voice + 1) % number_of_voices;
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}
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void voice_deiterate() {
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voice = (voice - 1) % number_of_voices;
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}
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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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uint16_t compensated_index = (uint16_t)((float)envelope_index * (880.0 / frequency));
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switch (voice) {
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case default_voice:
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note_timbre = TIMBRE_50;
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polyphony_rate = 0;
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break;
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case butts_fader:
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polyphony_rate = 0;
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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 = .125 - pow(((float)compensated_index - 20) / (200 - 20), 2)*.125;
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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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polyphony_rate = 0;
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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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polyphony_rate = 0;
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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 = (float)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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polyphony_rate = 0;
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note_timbre = (envelope_index % 2) * .125 + .375 * 2;
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if ((envelope_index % 4) == 0)
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note_timbre = 0.5;
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if ((envelope_index % 8) == 0)
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note_timbre = 0;
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break;
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case duty_fifth_down:
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note_timbre = 0.5;
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if ((envelope_index % 5) == 0)
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note_timbre = 0.75;
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break;
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case duty_fourth_down:
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if ((envelope_index % 12) == 0)
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note_timbre = 0.25;
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else
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note_timbre = 0.5;
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break;
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}
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return frequency;
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} |