4 // these are imported from audio.c
5 extern uint16_t envelope_index;
6 extern float note_timbre;
7 extern float polyphony_rate;
9 voice_type voice = default_voice;
11 void set_voice(voice_type v) {
15 void voice_iterate() {
16 voice = (voice + 1) % number_of_voices;
19 void voice_deiterate() {
20 voice = (voice - 1) % number_of_voices;
23 float voice_envelope(float frequency) {
24 // envelope_index ranges from 0 to 0xFFFF, which is preserved at 880.0 Hz
25 uint16_t compensated_index = (uint16_t)((float)envelope_index * (880.0 / frequency));
29 note_timbre = TIMBRE_50;
35 switch (compensated_index) {
37 frequency = frequency / 4;
38 note_timbre = TIMBRE_12;
42 frequency = frequency / 2;
43 note_timbre = TIMBRE_12;
47 note_timbre = .125 - pow(((float)compensated_index - 20) / (200 - 20), 2)*.125;
58 switch (compensated_index) {
62 frequency = frequency / 2;
63 note_timbre = TIMBRE_12;
69 frequency = frequency * 2;
70 note_timbre = TIMBRE_12;
74 note_timbre = TIMBRE_12;
80 // This slows the loop down a substantial amount, so higher notes may freeze
82 switch (compensated_index) {
87 // note_timbre = (sin((float)compensated_index/10000*OCS_SPEED) * OCS_AMP / 2) + .5;
88 // triangle wave is a bit faster
89 note_timbre = (float)abs((compensated_index*OCS_SPEED % 3000) - 1500) * ( OCS_AMP / 1500 ) + (1 - OCS_AMP) / 2;
94 case duty_octave_down:
96 note_timbre = (envelope_index % 2) * .125 + .375 * 2;
97 if ((envelope_index % 4) == 0)
99 if ((envelope_index % 8) == 0)
102 // case duty_fifth_down:
103 // note_timbre = 0.5;
104 // if ((envelope_index % 3) == 0)
105 // note_timbre = 0.75;
107 // case duty_fourth_down:
108 // note_timbre = 0.0;
109 // if ((envelope_index % 12) == 0)
110 // note_timbre = 0.75;
111 // if (((envelope_index % 12) % 4) != 1)
112 // note_timbre = 0.75;
114 // case duty_third_down:
115 // note_timbre = 0.5;
116 // if ((envelope_index % 5) == 0)
117 // note_timbre = 0.75;
119 // case duty_fifth_third_down:
120 // note_timbre = 0.5;
121 // if ((envelope_index % 5) == 0)
122 // note_timbre = 0.75;
123 // if ((envelope_index % 3) == 0)
124 // note_timbre = 0.25;