sequencer.h
4435 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#pragma once
18
19#include <stdbool.h>
20#include <stdint.h>
21
22// Maximum number of steps: 256
23#ifndef SEQUENCER_STEPS
24# define SEQUENCER_STEPS 16
25#endif
26
27// Maximum number of tracks: 8
28#ifndef SEQUENCER_TRACKS
29# define SEQUENCER_TRACKS 8
30#endif
31
32#ifndef SEQUENCER_TRACK_THROTTLE
33# define SEQUENCER_TRACK_THROTTLE 3
34#endif
35
36#ifndef SEQUENCER_PHASE_RELEASE_TIMEOUT
37# define SEQUENCER_PHASE_RELEASE_TIMEOUT 30
38#endif
39
40/**
41 * Make sure that the items of this enumeration follow the powers of 2, separated by a ternary variant.
42 * Check the implementation of `get_step_duration` for further explanation.
43 */
44typedef enum {
45 SQ_RES_2, //
46 SQ_RES_2T,
47 SQ_RES_4,
48 SQ_RES_4T,
49 SQ_RES_8,
50 SQ_RES_8T,
51 SQ_RES_16,
52 SQ_RES_16T,
53 SQ_RES_32,
54 SEQUENCER_RESOLUTIONS
55} sequencer_resolution_t;
56
57typedef struct {
58 bool enabled;
59 uint8_t steps[SEQUENCER_STEPS];
60 uint16_t track_notes[SEQUENCER_TRACKS];
61 uint8_t tempo; // Is a maximum tempo of 255 reasonable?
62 sequencer_resolution_t resolution;
63} sequencer_config_t;
64
65/**
66 * Because Digital Audio Workstations get overwhelmed when too many MIDI signals are sent concurrently,
67 * We use a "phase" state machine to delay some of the events.
68 */
69typedef enum sequencer_phase_t {
70 SEQUENCER_PHASE_ATTACK, // t=0ms, send the MIDI note on signal
71 SEQUENCER_PHASE_RELEASE, // t=SEQUENCER_PHASE_RELEASE_TIMEOUT ms, send the MIDI note off signal
72 SEQUENCER_PHASE_PAUSE // t=step duration ms, loop
73} sequencer_phase_t;
74
75typedef struct {
76 uint8_t active_tracks;
77 uint8_t current_track;
78 uint8_t current_step;
79 uint16_t timer;
80 sequencer_phase_t phase;
81} sequencer_state_t;
82
83extern sequencer_config_t sequencer_config;
84
85// We expose the internal state to make the feature more "unit-testable"
86extern sequencer_state_t sequencer_internal_state;
87
88bool is_sequencer_on(void);
89void sequencer_toggle(void);
90void sequencer_on(void);
91void sequencer_off(void);
92
93void sequencer_set_track_notes(const uint16_t track_notes[SEQUENCER_TRACKS]);
94
95bool is_sequencer_track_active(uint8_t track);
96void sequencer_set_track_activation(uint8_t track, bool value);
97void sequencer_toggle_track_activation(uint8_t track);
98void sequencer_toggle_single_active_track(uint8_t track);
99
100#define sequencer_activate_track(track) sequencer_set_track_activation(track, true)
101#define sequencer_deactivate_track(track) sequencer_set_track_activation(track, false)
102
103bool is_sequencer_step_on(uint8_t step);
104bool is_sequencer_step_on_for_track(uint8_t step, uint8_t track);
105void sequencer_set_step(uint8_t step, bool value);
106void sequencer_toggle_step(uint8_t step);
107void sequencer_set_all_steps(bool value);
108
109#define sequencer_set_step_on(step) sequencer_set_step(step, true)
110#define sequencer_set_step_off(step) sequencer_set_step(step, false)
111#define sequencer_set_all_steps_on() sequencer_set_all_steps(true)
112#define sequencer_set_all_steps_off() sequencer_set_all_steps(false)
113
114uint8_t sequencer_get_tempo(void);
115void sequencer_set_tempo(uint8_t tempo);
116void sequencer_increase_tempo(void);
117void sequencer_decrease_tempo(void);
118
119sequencer_resolution_t sequencer_get_resolution(void);
120void sequencer_set_resolution(sequencer_resolution_t resolution);
121void sequencer_increase_resolution(void);
122void sequencer_decrease_resolution(void);
123
124uint8_t sequencer_get_current_step(void);
125
126uint16_t sequencer_get_beat_duration(void);
127uint16_t sequencer_get_step_duration(void);
128
129uint16_t get_beat_duration(uint8_t tempo);
130uint16_t get_step_duration(uint8_t tempo, sequencer_resolution_t resolution);
131
132void sequencer_task(void);