sequencer.c
9550 bytes
1/* Copyright 2020 Rodolphe Belouin
2 *
3 * This program is free software: you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation, either version 2 of the License, or
6 * (at your option) any later version.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
15 */
16
17#include "sequencer.h"
18#include "debug.h"
19#include "timer.h"
20
21#ifdef MIDI_ENABLE
22# include "process_midi.h"
23#endif
24
25#ifdef MIDI_MOCKED
26# include "tests/midi_mock.h"
27#endif
28
29sequencer_config_t sequencer_config = {
30 false, // enabled
31 {false}, // steps
32 {0}, // track notes
33 60, // tempo
34 SQ_RES_4, // resolution
35};
36
37sequencer_state_t sequencer_internal_state = {0, 0, 0, 0, SEQUENCER_PHASE_ATTACK};
38
39bool is_sequencer_on(void) {
40 return sequencer_config.enabled;
41}
42
43void sequencer_on(void) {
44 dprintln("sequencer on");
45 sequencer_config.enabled = true;
46 sequencer_internal_state.current_track = 0;
47 sequencer_internal_state.current_step = 0;
48 sequencer_internal_state.timer = timer_read();
49 sequencer_internal_state.phase = SEQUENCER_PHASE_ATTACK;
50}
51
52void sequencer_off(void) {
53 dprintln("sequencer off");
54 sequencer_config.enabled = false;
55 sequencer_internal_state.current_step = 0;
56}
57
58void sequencer_toggle(void) {
59 if (is_sequencer_on()) {
60 sequencer_off();
61 } else {
62 sequencer_on();
63 }
64}
65
66void sequencer_set_track_notes(const uint16_t track_notes[SEQUENCER_TRACKS]) {
67 for (uint8_t i = 0; i < SEQUENCER_TRACKS; i++) {
68 sequencer_config.track_notes[i] = track_notes[i];
69 }
70}
71
72bool is_sequencer_track_active(uint8_t track) {
73 return (sequencer_internal_state.active_tracks >> track) & true;
74}
75
76void sequencer_set_track_activation(uint8_t track, bool value) {
77 if (value) {
78 sequencer_internal_state.active_tracks |= (1 << track);
79 } else {
80 sequencer_internal_state.active_tracks &= ~(1 << track);
81 }
82 dprintf("sequencer: track %d is %s\n", track, value ? "active" : "inactive");
83}
84
85void sequencer_toggle_track_activation(uint8_t track) {
86 sequencer_set_track_activation(track, !is_sequencer_track_active(track));
87}
88
89void sequencer_toggle_single_active_track(uint8_t track) {
90 if (is_sequencer_track_active(track)) {
91 sequencer_internal_state.active_tracks = 0;
92 } else {
93 sequencer_internal_state.active_tracks = 1 << track;
94 }
95}
96
97bool is_sequencer_step_on(uint8_t step) {
98 return step < SEQUENCER_STEPS && (sequencer_config.steps[step] & sequencer_internal_state.active_tracks) > 0;
99}
100
101bool is_sequencer_step_on_for_track(uint8_t step, uint8_t track) {
102 return step < SEQUENCER_STEPS && (sequencer_config.steps[step] >> track) & true;
103}
104
105void sequencer_set_step(uint8_t step, bool value) {
106 if (step < SEQUENCER_STEPS) {
107 if (value) {
108 sequencer_config.steps[step] |= sequencer_internal_state.active_tracks;
109 } else {
110 sequencer_config.steps[step] &= ~sequencer_internal_state.active_tracks;
111 }
112 dprintf("sequencer: step %d is %s\n", step, value ? "on" : "off");
113 } else {
114 dprintf("sequencer: step %d is out of range\n", step);
115 }
116}
117
118void sequencer_toggle_step(uint8_t step) {
119 if (is_sequencer_step_on(step)) {
120 sequencer_set_step_off(step);
121 } else {
122 sequencer_set_step_on(step);
123 }
124}
125
126void sequencer_set_all_steps(bool value) {
127 for (uint8_t step = 0; step < SEQUENCER_STEPS; step++) {
128 if (value) {
129 sequencer_config.steps[step] |= sequencer_internal_state.active_tracks;
130 } else {
131 sequencer_config.steps[step] &= ~sequencer_internal_state.active_tracks;
132 }
133 }
134 dprintf("sequencer: all steps are %s\n", value ? "on" : "off");
135}
136
137uint8_t sequencer_get_tempo(void) {
138 return sequencer_config.tempo;
139}
140
141void sequencer_set_tempo(uint8_t tempo) {
142 if (tempo > 0) {
143 sequencer_config.tempo = tempo;
144 dprintf("sequencer: tempo set to %d bpm\n", tempo);
145 } else {
146 dprintln("sequencer: cannot set tempo to 0");
147 }
148}
149
150void sequencer_increase_tempo(void) {
151 // Handling potential uint8_t overflow
152 if (sequencer_config.tempo < UINT8_MAX) {
153 sequencer_set_tempo(sequencer_config.tempo + 1);
154 } else {
155 dprintf("sequencer: cannot set tempo above %d\n", UINT8_MAX);
156 }
157}
158
159void sequencer_decrease_tempo(void) {
160 sequencer_set_tempo(sequencer_config.tempo - 1);
161}
162
163sequencer_resolution_t sequencer_get_resolution(void) {
164 return sequencer_config.resolution;
165}
166
167void sequencer_set_resolution(sequencer_resolution_t resolution) {
168 if (resolution >= 0 && resolution < SEQUENCER_RESOLUTIONS) {
169 sequencer_config.resolution = resolution;
170 dprintf("sequencer: resolution set to %d\n", resolution);
171 } else {
172 dprintf("sequencer: resolution %d is out of range\n", resolution);
173 }
174}
175
176void sequencer_increase_resolution(void) {
177 sequencer_set_resolution(sequencer_config.resolution + 1);
178}
179
180void sequencer_decrease_resolution(void) {
181 sequencer_set_resolution(sequencer_config.resolution - 1);
182}
183
184uint8_t sequencer_get_current_step(void) {
185 return sequencer_internal_state.current_step;
186}
187
188void sequencer_phase_attack(void) {
189 dprintf("sequencer: step %d\n", sequencer_internal_state.current_step);
190 dprintf("sequencer: time %d\n", timer_read());
191
192 if (sequencer_internal_state.current_track == 0) {
193 sequencer_internal_state.timer = timer_read();
194 }
195
196 if (timer_elapsed(sequencer_internal_state.timer) < sequencer_internal_state.current_track * SEQUENCER_TRACK_THROTTLE) {
197 return;
198 }
199
200#if defined(MIDI_ENABLE) || defined(MIDI_MOCKED)
201 if (is_sequencer_step_on_for_track(sequencer_internal_state.current_step, sequencer_internal_state.current_track)) {
202 process_midi_basic_noteon(midi_compute_note(sequencer_config.track_notes[sequencer_internal_state.current_track]));
203 }
204#endif
205
206 if (sequencer_internal_state.current_track < SEQUENCER_TRACKS - 1) {
207 sequencer_internal_state.current_track++;
208 } else {
209 sequencer_internal_state.phase = SEQUENCER_PHASE_RELEASE;
210 }
211}
212
213void sequencer_phase_release(void) {
214 if (timer_elapsed(sequencer_internal_state.timer) < SEQUENCER_PHASE_RELEASE_TIMEOUT + sequencer_internal_state.current_track * SEQUENCER_TRACK_THROTTLE) {
215 return;
216 }
217#if defined(MIDI_ENABLE) || defined(MIDI_MOCKED)
218 if (is_sequencer_step_on_for_track(sequencer_internal_state.current_step, sequencer_internal_state.current_track)) {
219 process_midi_basic_noteoff(midi_compute_note(sequencer_config.track_notes[sequencer_internal_state.current_track]));
220 }
221#endif
222 if (sequencer_internal_state.current_track > 0) {
223 sequencer_internal_state.current_track--;
224 } else {
225 sequencer_internal_state.phase = SEQUENCER_PHASE_PAUSE;
226 }
227}
228
229void sequencer_phase_pause(void) {
230 if (timer_elapsed(sequencer_internal_state.timer) < sequencer_get_step_duration()) {
231 return;
232 }
233
234 sequencer_internal_state.current_step = (sequencer_internal_state.current_step + 1) % SEQUENCER_STEPS;
235 sequencer_internal_state.phase = SEQUENCER_PHASE_ATTACK;
236}
237
238void sequencer_task(void) {
239 if (!sequencer_config.enabled) {
240 return;
241 }
242
243 if (sequencer_internal_state.phase == SEQUENCER_PHASE_PAUSE) {
244 sequencer_phase_pause();
245 }
246
247 if (sequencer_internal_state.phase == SEQUENCER_PHASE_RELEASE) {
248 sequencer_phase_release();
249 }
250
251 if (sequencer_internal_state.phase == SEQUENCER_PHASE_ATTACK) {
252 sequencer_phase_attack();
253 }
254}
255
256uint16_t sequencer_get_beat_duration(void) {
257 return get_beat_duration(sequencer_config.tempo);
258}
259
260uint16_t sequencer_get_step_duration(void) {
261 return get_step_duration(sequencer_config.tempo, sequencer_config.resolution);
262}
263
264uint16_t get_beat_duration(uint8_t tempo) {
265 // Don’t crash in the unlikely case where the given tempo is 0
266 if (tempo == 0) {
267 return get_beat_duration(60);
268 }
269
270 /**
271 * Given
272 * t = tempo and d = duration, both strictly greater than 0
273 * When
274 * t beats / minute = 1 beat / d ms
275 * Then
276 * t beats / 60000ms = 1 beat / d ms
277 * d ms = 60000ms / t
278 */
279 return 60000 / tempo;
280}
281
282uint16_t get_step_duration(uint8_t tempo, sequencer_resolution_t resolution) {
283 /**
284 * Resolution cheatsheet:
285 * 1/2 => 2 steps per 4 beats
286 * 1/2T => 3 steps per 4 beats
287 * 1/4 => 4 steps per 4 beats
288 * 1/4T => 6 steps per 4 beats
289 * 1/8 => 8 steps per 4 beats
290 * 1/8T => 12 steps per 4 beats
291 * 1/16 => 16 steps per 4 beats
292 * 1/16T => 24 steps per 4 beats
293 * 1/32 => 32 steps per 4 beats
294 *
295 * The number of steps for binary resolutions follows the powers of 2.
296 * The ternary variants are simply 1.5x faster.
297 */
298 bool is_binary = resolution % 2 == 0;
299 uint8_t binary_steps = 2 << (resolution / 2);
300 uint16_t binary_step_duration = get_beat_duration(tempo) * 4 / binary_steps;
301
302 return is_binary ? binary_step_duration : 2 * binary_step_duration / 3;
303}