synthio: add Synthesizer.lfo, retrigger option

shared-bindings/synthio/Synthesizer.c

@@ -33,6 +33,7 @@
 #include "py/runtime.h"
 #include "shared-bindings/util.h"
 #include "shared-bindings/synthio/Synthesizer.h"
+#include "shared-bindings/synthio/LFO.h"
 #include "shared-bindings/synthio/__init__.h"
 #include "supervisor/shared/translate/translate.h"
 
@@ -120,23 +121,29 @@ STATIC mp_obj_t synthio_synthesizer_release(mp_obj_t self_in, mp_obj_t release)
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_2(synthio_synthesizer_release_obj, synthio_synthesizer_release);
 
-//|     def release_then_press(self, release: NoteSequence = (), press: NoteSequence = ()) -> None:
+//|     def release_then_press(
+//|         self, release: NoteSequence = (), press: NoteSequence = (), retrigger=LFOSequence
+//|     ) -> None:
 //|         """Turn some notes on and/or off.
 //|
 //|         It is OK to release note that was not actually turned on.
 //|
-//|         Pressing a note that was already pressed has no effect.
+//|         Pressing a note that was already pressed returns it to the attack phase
+//|         but without resetting its amplitude. Releasing a note and immediately
+//|         pressing it again returns it to the attack phase with an initial
+//|         amplitude of 0.
 //|
-//|         Releasing and pressing the note again has little effect, but does reset the phase
-//|         of the note, which may be perceptible as a small glitch.
+//|         At the same time, the passed LFOs (if any) are retriggered.
 //|
 //|         :param NoteSequence release: Any sequence of notes.
-//|         :param NoteSequence press: Any sequence of notes."""
+//|         :param NoteSequence press: Any sequence of notes.
+//|         :param LFOSequence retrigger: Any sequence of LFOs."""
 STATIC mp_obj_t synthio_synthesizer_release_then_press(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_release, ARG_press };
+    enum { ARG_release, ARG_press, ARG_retrigger };
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_release, MP_ARG_OBJ, {.u_obj = mp_const_empty_tuple } },
         { MP_QSTR_press, MP_ARG_OBJ, {.u_obj = mp_const_empty_tuple } },
+        { MP_QSTR_retrigger, MP_ARG_OBJ, {.u_obj = mp_const_empty_tuple } },
     };
 
     mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
@@ -146,6 +153,7 @@ STATIC mp_obj_t synthio_synthesizer_release_then_press(mp_uint_t n_args, const m
     check_for_deinit(self);
     common_hal_synthio_synthesizer_release(self, args[ARG_release].u_obj);
     common_hal_synthio_synthesizer_press(self, args[ARG_press].u_obj);
+    common_hal_synthio_synthesizer_retrigger(self, args[ARG_retrigger].u_obj);
     return mp_const_none;
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_KW(synthio_synthesizer_release_then_press_obj, 1, synthio_synthesizer_release_then_press);
@@ -250,6 +258,23 @@ MP_DEFINE_CONST_FUN_OBJ_1(synthio_synthesizer_get_pressed_obj, synthio_synthesiz
 MP_PROPERTY_GETTER(synthio_synthesizer_pressed_obj,
     (mp_obj_t)&synthio_synthesizer_get_pressed_obj);
 
+//|     lfos: List[LFO]
+//|     """A list of LFOs to advance whether or not they are associated with a playing note.
+//|
+//|     This can be used to implement 'free-running' LFOs. LFOs associated with playing notes are advanced whether or not they are in this list.
+//|
+//|     This attribute is read-only but its contents may be modified by e.g., calling append() or remove(). It is initially an empty list."""
+//|
+STATIC mp_obj_t synthio_synthesizer_obj_get_lfos(mp_obj_t self_in) {
+    synthio_synthesizer_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    check_for_deinit(self);
+    return common_hal_synthio_synthesizer_get_lfos(self);
+}
+MP_DEFINE_CONST_FUN_OBJ_1(synthio_synthesizer_get_lfos_obj, synthio_synthesizer_obj_get_lfos);
+
+MP_PROPERTY_GETTER(synthio_synthesizer_lfos_obj,
+    (mp_obj_t)&synthio_synthesizer_get_lfos_obj);
+
 //|     max_polyphony: int
 //|     """Maximum polyphony of the synthesizer (read-only class property)"""
 //|
@@ -270,6 +295,7 @@ STATIC const mp_rom_map_elem_t synthio_synthesizer_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_sample_rate), MP_ROM_PTR(&synthio_synthesizer_sample_rate_obj) },
     { MP_ROM_QSTR(MP_QSTR_max_polyphony), MP_ROM_INT(CIRCUITPY_SYNTHIO_MAX_CHANNELS) },
     { MP_ROM_QSTR(MP_QSTR_pressed), MP_ROM_PTR(&synthio_synthesizer_pressed_obj) },
+    { MP_ROM_QSTR(MP_QSTR_lfos), MP_ROM_PTR(&synthio_synthesizer_lfos_obj) },
 };
 STATIC MP_DEFINE_CONST_DICT(synthio_synthesizer_locals_dict, synthio_synthesizer_locals_dict_table);
 

shared-bindings/synthio/Synthesizer.h

@@ -41,5 +41,7 @@ uint8_t common_hal_synthio_synthesizer_get_bits_per_sample(synthio_synthesizer_o
 uint8_t common_hal_synthio_synthesizer_get_channel_count(synthio_synthesizer_obj_t *self);
 void common_hal_synthio_synthesizer_release(synthio_synthesizer_obj_t *self, mp_obj_t to_release);
 void common_hal_synthio_synthesizer_press(synthio_synthesizer_obj_t *self, mp_obj_t to_press);
+void common_hal_synthio_synthesizer_retrigger(synthio_synthesizer_obj_t *self, mp_obj_t to_retrigger);
 void common_hal_synthio_synthesizer_release_all(synthio_synthesizer_obj_t *self);
 mp_obj_t common_hal_synthio_synthesizer_get_pressed_notes(synthio_synthesizer_obj_t *self);
+mp_obj_t common_hal_synthio_synthesizer_get_lfos(synthio_synthesizer_obj_t *self);

shared-module/synthio/Synthesizer.c

@@ -25,8 +25,9 @@
  */
 
 #include "py/runtime.h"
-#include "shared-bindings/synthio/Synthesizer.h"
+#include "shared-bindings/synthio/LFO.h"
 #include "shared-bindings/synthio/Note.h"
+#include "shared-bindings/synthio/Synthesizer.h"
 #include "shared-module/synthio/Note.h"
 
 
@@ -36,6 +37,7 @@ void common_hal_synthio_synthesizer_construct(synthio_synthesizer_obj_t *self,
     mp_obj_t envelope_obj) {
 
     synthio_synth_init(&self->synth, sample_rate, channel_count, waveform_obj, filter_obj, envelope_obj);
+    self->lfos = mp_obj_new_list(0, NULL);
 }
 
 void common_hal_synthio_synthesizer_deinit(synthio_synthesizer_obj_t *self) {
@@ -67,7 +69,20 @@ audioio_get_buffer_result_t synthio_synthesizer_get_buffer(synthio_synthesizer_o
         return GET_BUFFER_ERROR;
     }
     self->synth.span.dur = SYNTHIO_MAX_DUR;
+
+
     synthio_synth_synthesize(&self->synth, buffer, buffer_length, single_channel_output ? channel : 0);
+
+    // free-running LFOs
+    mp_obj_iter_buf_t iter_buf;
+    mp_obj_t iterable = mp_getiter(self->lfos, &iter_buf);
+    mp_obj_t item;
+    while ((item = mp_iternext(iterable)) != MP_OBJ_STOP_ITERATION) {
+        synthio_lfo_slot_t slot = { .obj = item };
+        // does not error for invalid type, so it's OK that we don't police
+        // list contents
+        (void)synthio_lfo_obj_tick(&slot);
+    }
     return GET_BUFFER_MORE_DATA;
 }
 
@@ -119,6 +134,16 @@ void common_hal_synthio_synthesizer_press(synthio_synthesizer_obj_t *self, mp_ob
     }
 }
 
+void common_hal_synthio_synthesizer_retrigger(synthio_synthesizer_obj_t *self, mp_obj_t to_retrigger) {
+    mp_obj_iter_buf_t iter_buf;
+    mp_obj_t iterable = mp_getiter(to_retrigger, &iter_buf);
+    mp_obj_t lfo_obj;
+    while ((lfo_obj = mp_iternext(iterable)) != MP_OBJ_STOP_ITERATION) {
+        synthio_lfo_obj_t *lfo = MP_OBJ_TO_PTR(mp_arg_validate_type(lfo_obj, &synthio_lfo_type, MP_QSTR_retrigger));
+        common_hal_synthio_lfo_retrigger(lfo);
+    }
+}
+
 mp_obj_t common_hal_synthio_synthesizer_get_pressed_notes(synthio_synthesizer_obj_t *self) {
     int count = 0;
     for (int chan = 0; chan < CIRCUITPY_SYNTHIO_MAX_CHANNELS; chan++) {
@@ -134,3 +159,7 @@ mp_obj_t common_hal_synthio_synthesizer_get_pressed_notes(synthio_synthesizer_ob
     }
     return MP_OBJ_FROM_PTR(result);
 }
+
+mp_obj_t common_hal_synthio_synthesizer_get_lfos(synthio_synthesizer_obj_t *self) {
+    return self->lfos;
+}

shared-module/synthio/Synthesizer.h

@@ -34,6 +34,7 @@
 typedef struct {
     mp_obj_base_t base;
     synthio_synth_t synth;
+    mp_obj_t lfos;
 } synthio_synthesizer_obj_t;