1 files changed, 275 insertions, 0 deletions

diff --git a/quantum/sequencer/sequencer.c b/quantum/sequencer/sequencer.c
new file mode 100644
index 000000000..0eaf3a17a
--- /dev/null
+++ b/quantum/sequencer/sequencer.c
@@ -0,0 +1,275 @@
+/* Copyright 2020 Rodolphe Belouin
+ *
+ * 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 "sequencer.h"
+
+#ifdef MIDI_ENABLE
+#    include "process_midi.h"
+#endif
+
+#ifdef MIDI_MOCKED
+#    include "tests/midi_mock.h"
+#endif
+
+sequencer_config_t sequencer_config = {
+    false,     // enabled
+    {false},   // steps
+    {0},       // track notes
+    60,        // tempo
+    SQ_RES_4,  // resolution
+};
+
+sequencer_state_t sequencer_internal_state = {0, 0, 0, 0, SEQUENCER_PHASE_ATTACK};
+
+bool is_sequencer_on(void) { return sequencer_config.enabled; }
+
+void sequencer_on(void) {
+    dprintln("sequencer on");
+    sequencer_config.enabled               = true;
+    sequencer_internal_state.current_track = 0;
+    sequencer_internal_state.current_step  = 0;
+    sequencer_internal_state.timer         = timer_read();
+    sequencer_internal_state.phase         = SEQUENCER_PHASE_ATTACK;
+}
+
+void sequencer_off(void) {
+    dprintln("sequencer off");
+    sequencer_config.enabled              = false;
+    sequencer_internal_state.current_step = 0;
+}
+
+void sequencer_toggle(void) {
+    if (is_sequencer_on()) {
+        sequencer_off();
+    } else {
+        sequencer_on();
+    }
+}
+
+void sequencer_set_track_notes(const uint16_t track_notes[SEQUENCER_TRACKS]) {
+    for (uint8_t i = 0; i < SEQUENCER_TRACKS; i++) {
+        sequencer_config.track_notes[i] = track_notes[i];
+    }
+}
+
+bool is_sequencer_track_active(uint8_t track) { return (sequencer_internal_state.active_tracks >> track) & true; }
+
+void sequencer_set_track_activation(uint8_t track, bool value) {
+    if (value) {
+        sequencer_internal_state.active_tracks |= (1 << track);
+    } else {
+        sequencer_internal_state.active_tracks &= ~(1 << track);
+    }
+    dprintf("sequencer: track %d is %s\n", track, value ? "active" : "inactive");
+}
+
+void sequencer_toggle_track_activation(uint8_t track) { sequencer_set_track_activation(track, !is_sequencer_track_active(track)); }
+
+void sequencer_toggle_single_active_track(uint8_t track) {
+    if (is_sequencer_track_active(track)) {
+        sequencer_internal_state.active_tracks = 0;
+    } else {
+        sequencer_internal_state.active_tracks = 1 << track;
+    }
+}
+
+bool is_sequencer_step_on(uint8_t step) { return step < SEQUENCER_STEPS && (sequencer_config.steps[step] & sequencer_internal_state.active_tracks) > 0; }
+
+bool is_sequencer_step_on_for_track(uint8_t step, uint8_t track) { return step < SEQUENCER_STEPS && (sequencer_config.steps[step] >> track) & true; }
+
+void sequencer_set_step(uint8_t step, bool value) {
+    if (step < SEQUENCER_STEPS) {
+        if (value) {
+            sequencer_config.steps[step] |= sequencer_internal_state.active_tracks;
+        } else {
+            sequencer_config.steps[step] &= ~sequencer_internal_state.active_tracks;
+        }
+        dprintf("sequencer: step %d is %s\n", step, value ? "on" : "off");
+    } else {
+        dprintf("sequencer: step %d is out of range\n", step);
+    }
+}
+
+void sequencer_toggle_step(uint8_t step) {
+    if (is_sequencer_step_on(step)) {
+        sequencer_set_step_off(step);
+    } else {
+        sequencer_set_step_on(step);
+    }
+}
+
+void sequencer_set_all_steps(bool value) {
+    for (uint8_t step = 0; step < SEQUENCER_STEPS; step++) {
+        if (value) {
+            sequencer_config.steps[step] |= sequencer_internal_state.active_tracks;
+        } else {
+            sequencer_config.steps[step] &= ~sequencer_internal_state.active_tracks;
+        }
+    }
+    dprintf("sequencer: all steps are %s\n", value ? "on" : "off");
+}
+
+uint8_t sequencer_get_tempo(void) { return sequencer_config.tempo; }
+
+void sequencer_set_tempo(uint8_t tempo) {
+    if (tempo > 0) {
+        sequencer_config.tempo = tempo;
+        dprintf("sequencer: tempo set to %d bpm\n", tempo);
+    } else {
+        dprintln("sequencer: cannot set tempo to 0");
+    }
+}
+
+void sequencer_increase_tempo(void) {
+    // Handling potential uint8_t overflow
+    if (sequencer_config.tempo < UINT8_MAX) {
+        sequencer_set_tempo(sequencer_config.tempo + 1);
+    } else {
+        dprintf("sequencer: cannot set tempo above %d\n", UINT8_MAX);
+    }
+}
+
+void sequencer_decrease_tempo(void) { sequencer_set_tempo(sequencer_config.tempo - 1); }
+
+sequencer_resolution_t sequencer_get_resolution(void) { return sequencer_config.resolution; }
+
+void sequencer_set_resolution(sequencer_resolution_t resolution) {
+    if (resolution >= 0 && resolution < SEQUENCER_RESOLUTIONS) {
+        sequencer_config.resolution = resolution;
+        dprintf("sequencer: resolution set to %d\n", resolution);
+    } else {
+        dprintf("sequencer: resolution %d is out of range\n", resolution);
+    }
+}
+
+void sequencer_increase_resolution(void) { sequencer_set_resolution(sequencer_config.resolution + 1); }
+
+void sequencer_decrease_resolution(void) { sequencer_set_resolution(sequencer_config.resolution - 1); }
+
+uint8_t sequencer_get_current_step(void) { return sequencer_internal_state.current_step; }
+
+void sequencer_phase_attack(void) {
+    dprintf("sequencer: step %d\n", sequencer_internal_state.current_step);
+    dprintf("sequencer: time %d\n", timer_read());
+
+    if (sequencer_internal_state.current_track == 0) {
+        sequencer_internal_state.timer = timer_read();
+    }
+
+    if (timer_elapsed(sequencer_internal_state.timer) < sequencer_internal_state.current_track * SEQUENCER_TRACK_THROTTLE) {
+        return;
+    }
+
+#if defined(MIDI_ENABLE) || defined(MIDI_MOCKED)
+    if (is_sequencer_step_on_for_track(sequencer_internal_state.current_step, sequencer_internal_state.current_track)) {
+        process_midi_basic_noteon(midi_compute_note(sequencer_config.track_notes[sequencer_internal_state.current_track]));
+    }
+#endif
+
+    if (sequencer_internal_state.current_track < SEQUENCER_TRACKS - 1) {
+        sequencer_internal_state.current_track++;
+    } else {
+        sequencer_internal_state.phase = SEQUENCER_PHASE_RELEASE;
+    }
+}
+
+void sequencer_phase_release(void) {
+    if (timer_elapsed(sequencer_internal_state.timer) < SEQUENCER_PHASE_RELEASE_TIMEOUT + sequencer_internal_state.current_track * SEQUENCER_TRACK_THROTTLE) {
+        return;
+    }
+#if defined(MIDI_ENABLE) || defined(MIDI_MOCKED)
+    if (is_sequencer_step_on_for_track(sequencer_internal_state.current_step, sequencer_internal_state.current_track)) {
+        process_midi_basic_noteoff(midi_compute_note(sequencer_config.track_notes[sequencer_internal_state.current_track]));
+    }
+#endif
+    if (sequencer_internal_state.current_track > 0) {
+        sequencer_internal_state.current_track--;
+    } else {
+        sequencer_internal_state.phase = SEQUENCER_PHASE_PAUSE;
+    }
+}
+
+void sequencer_phase_pause(void) {
+    if (timer_elapsed(sequencer_internal_state.timer) < sequencer_get_step_duration()) {
+        return;
+    }
+
+    sequencer_internal_state.current_step = (sequencer_internal_state.current_step + 1) % SEQUENCER_STEPS;
+    sequencer_internal_state.phase        = SEQUENCER_PHASE_ATTACK;
+}
+
+void matrix_scan_sequencer(void) {
+    if (!sequencer_config.enabled) {
+        return;
+    }
+
+    if (sequencer_internal_state.phase == SEQUENCER_PHASE_PAUSE) {
+        sequencer_phase_pause();
+    }
+
+    if (sequencer_internal_state.phase == SEQUENCER_PHASE_RELEASE) {
+        sequencer_phase_release();
+    }
+
+    if (sequencer_internal_state.phase == SEQUENCER_PHASE_ATTACK) {
+        sequencer_phase_attack();
+    }
+}
+
+uint16_t sequencer_get_beat_duration(void) { return get_beat_duration(sequencer_config.tempo); }
+
+uint16_t sequencer_get_step_duration(void) { return get_step_duration(sequencer_config.tempo, sequencer_config.resolution); }
+
+uint16_t get_beat_duration(uint8_t tempo) {
+    // Don’t crash in the unlikely case where the given tempo is 0
+    if (tempo == 0) {
+        return get_beat_duration(60);
+    }
+
+    /**
+     * Given
+     *  t = tempo and d = duration, both strictly greater than 0
+     * When
+     *  t beats / minute = 1 beat / d ms
+     * Then
+     *  t beats / 60000ms = 1 beat / d ms
+     *  d ms = 60000ms / t
+     */
+    return 60000 / tempo;
+}
+
+uint16_t get_step_duration(uint8_t tempo, sequencer_resolution_t resolution) {
+    /**
+     * Resolution cheatsheet:
+     * 1/2  => 2 steps per 4 beats
+     * 1/2T => 3 steps per 4 beats
+     * 1/4  => 4 steps per 4 beats
+     * 1/4T => 6 steps per 4 beats
+     * 1/8  => 8 steps per 4 beats
+     * 1/8T => 12 steps per 4 beats
+     * 1/16 => 16 steps per 4 beats
+     * 1/16T => 24 steps per 4 beats
+     * 1/32 => 32 steps per 4 beats
+     *
+     * The number of steps for binary resolutions follows the powers of 2.
+     * The ternary variants are simply 1.5x faster.
+     */
+    bool     is_binary            = resolution % 2 == 0;
+    uint8_t  binary_steps         = 2 << (resolution / 2);
+    uint16_t binary_step_duration = get_beat_duration(tempo) * 4 / binary_steps;
+
+    return is_binary ? binary_step_duration : 2 * binary_step_duration / 3;
+}