synthio: Add Synthesizer.note_state

This enables the specific use case of checking whether a note's release
phase has ended, but is also potentially useful to implement a sort of
"voice stealing" algorithm in Python code, which can take account of
the note's envelope state as well as other factors specific to the
program.

shared-bindings/synthio/Synthesizer.c

@@ -31,6 +31,7 @@
 #include "py/binary.h"
 #include "py/objproperty.h"
 #include "py/runtime.h"
+#include "py/enum.h"
 #include "shared-bindings/util.h"
 #include "shared-bindings/synthio/Biquad.h"
 #include "shared-bindings/synthio/Synthesizer.h"
@@ -256,7 +257,9 @@ MP_PROPERTY_GETTER(synthio_synthesizer_sample_rate_obj,
     (mp_obj_t)&synthio_synthesizer_get_sample_rate_obj);
 
 //|     pressed: NoteSequence
-//|     """A sequence of the currently pressed notes (read-only property)"""
+//|     """A sequence of the currently pressed notes (read-only property).
+//|
+//|     This does not include notes in the release phase of the envelope."""
 //|
 STATIC mp_obj_t synthio_synthesizer_obj_get_pressed(mp_obj_t self_in) {
     synthio_synthesizer_obj_t *self = MP_OBJ_TO_PTR(self_in);
@@ -268,6 +271,23 @@ 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);
 
+//|     def note_info(note: Note) -> Tuple[Optional[EnvelopeState], float]:
+//|         """Get info about a note's current envelope state
+//|
+//|         If the note is currently playing (including in the release phase), the returned value gives the current envelope state and the current envelope value.
+//|
+//|         If the note is not playing on this synthesizer, returns the tuple ``(None, 0.0)``."""
+STATIC mp_obj_t synthio_synthesizer_obj_note_info(mp_obj_t self_in, mp_obj_t note) {
+    synthio_synthesizer_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    check_for_deinit(self);
+    mp_float_t vol = MICROPY_FLOAT_CONST(0.0);
+    envelope_state_e state = common_hal_synthio_synthesizer_note_info(self, note, &vol);
+    return MP_OBJ_NEW_TUPLE(
+        cp_enum_find(&synthio_note_state_type, state),
+        mp_obj_new_float(vol));
+}
+MP_DEFINE_CONST_FUN_OBJ_2(synthio_synthesizer_note_info_obj, synthio_synthesizer_obj_note_info);
+
 //|     blocks: List[BlockInput]
 //|     """A list of blocks to advance whether or not they are associated with a playing note.
 //|
@@ -417,6 +437,7 @@ 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_note_info), MP_ROM_PTR(&synthio_synthesizer_note_info_obj) },
     { MP_ROM_QSTR(MP_QSTR_blocks), MP_ROM_PTR(&synthio_synthesizer_blocks_obj) },
 };
 STATIC MP_DEFINE_CONST_DICT(synthio_synthesizer_locals_dict, synthio_synthesizer_locals_dict_table);

shared-bindings/synthio/Synthesizer.h

@@ -45,3 +45,4 @@ void common_hal_synthio_synthesizer_retrigger(synthio_synthesizer_obj_t *self, m
 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_blocks(synthio_synthesizer_obj_t *self);
+envelope_state_e common_hal_synthio_synthesizer_note_info(synthio_synthesizer_obj_t *self, mp_obj_t note, mp_float_t *vol_out);

shared-bindings/synthio/__init__.c

@@ -45,6 +45,22 @@
 
 #include "shared-module/synthio/LFO.h"
 
+MAKE_ENUM_VALUE(synthio_note_state_type, note_state, ATTACK, SYNTHIO_ENVELOPE_STATE_ATTACK);
+MAKE_ENUM_VALUE(synthio_note_state_type, note_state, DECAY, SYNTHIO_ENVELOPE_STATE_DECAY);
+MAKE_ENUM_VALUE(synthio_note_state_type, note_state, SUSTAIN, SYNTHIO_ENVELOPE_STATE_SUSTAIN);
+MAKE_ENUM_VALUE(synthio_note_state_type, note_state, RELEASE, SYNTHIO_ENVELOPE_STATE_RELEASE);
+
+MAKE_ENUM_MAP(synthio_note_state) {
+    MAKE_ENUM_MAP_ENTRY(note_state, ATTACK),
+    MAKE_ENUM_MAP_ENTRY(note_state, DECAY),
+    MAKE_ENUM_MAP_ENTRY(note_state, SUSTAIN),
+    MAKE_ENUM_MAP_ENTRY(note_state, RELEASE),
+};
+
+STATIC MP_DEFINE_CONST_DICT(synthio_note_state_locals_dict, synthio_note_state_locals_table);
+MAKE_PRINTER(synthio, synthio_note_state);
+MAKE_ENUM_TYPE(synthio, NoteState, synthio_note_state);
+
 #define default_attack_time (MICROPY_FLOAT_CONST(0.1))
 #define default_decay_time (MICROPY_FLOAT_CONST(0.05))
 #define default_release_time (MICROPY_FLOAT_CONST(0.2))
@@ -316,6 +332,7 @@ STATIC const mp_rom_map_elem_t synthio_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_MathOperation), MP_ROM_PTR(&synthio_math_operation_type) },
     { MP_ROM_QSTR(MP_QSTR_MidiTrack), MP_ROM_PTR(&synthio_miditrack_type) },
     { MP_ROM_QSTR(MP_QSTR_Note), MP_ROM_PTR(&synthio_note_type) },
+    { MP_ROM_QSTR(MP_QSTR_NoteState), MP_ROM_PTR(&synthio_note_state_type) },
     { MP_ROM_QSTR(MP_QSTR_LFO), MP_ROM_PTR(&synthio_lfo_type) },
     { MP_ROM_QSTR(MP_QSTR_Synthesizer), MP_ROM_PTR(&synthio_synthesizer_type) },
     { MP_ROM_QSTR(MP_QSTR_from_file), MP_ROM_PTR(&synthio_from_file_obj) },

shared-bindings/synthio/__init__.h

@@ -29,10 +29,16 @@
 #include "py/objnamedtuple.h"
 #include "py/enum.h"
 
+typedef enum {
+    SYNTHIO_ENVELOPE_STATE_ATTACK, SYNTHIO_ENVELOPE_STATE_DECAY,
+    SYNTHIO_ENVELOPE_STATE_SUSTAIN, SYNTHIO_ENVELOPE_STATE_RELEASE
+} envelope_state_e;
+
 typedef enum synthio_bend_mode_e {
     SYNTHIO_BEND_MODE_STATIC, SYNTHIO_BEND_MODE_VIBRATO, SYNTHIO_BEND_MODE_SWEEP, SYNTHIO_BEND_MODE_SWEEP_IN
 } synthio_bend_mode_t;
 
+extern const mp_obj_type_t synthio_note_state_type;
 extern const cp_enum_obj_t bend_mode_VIBRATO_obj;
 extern const mp_obj_type_t synthio_bend_mode_type;
 typedef struct synthio_synth synthio_synth_t;

shared-module/synthio/Synthesizer.c

@@ -185,6 +185,17 @@ mp_obj_t common_hal_synthio_synthesizer_get_pressed_notes(synthio_synthesizer_ob
     return MP_OBJ_FROM_PTR(result);
 }
 
+envelope_state_e common_hal_synthio_synthesizer_note_info(synthio_synthesizer_obj_t *self, mp_obj_t note, mp_float_t *vol_out) {
+    for (int chan = 0; chan < CIRCUITPY_SYNTHIO_MAX_CHANNELS; chan++) {
+        if (self->synth.span.note_obj[chan] == note) {
+            *vol_out = self->synth.envelope_state[chan].level / 32767.;
+            return self->synth.envelope_state[chan].state;
+        }
+    }
+    return (envelope_state_e) - 1;
+}
+
+
 mp_obj_t common_hal_synthio_synthesizer_get_blocks(synthio_synthesizer_obj_t *self) {
     return self->blocks;
 }

shared-module/synthio/__init__.h

@@ -35,6 +35,7 @@
 #define SYNTHIO_FREQUENCY_SHIFT (16)
 
 #include "shared-module/audiocore/__init__.h"
+#include "shared-bindings/synthio/__init__.h"
 
 typedef struct {
     uint16_t dur;
@@ -49,11 +50,6 @@ typedef struct {
     uint16_t attack_level, sustain_level;
 } synthio_envelope_definition_t;
 
-typedef enum {
-    SYNTHIO_ENVELOPE_STATE_ATTACK, SYNTHIO_ENVELOPE_STATE_DECAY,
-    SYNTHIO_ENVELOPE_STATE_SUSTAIN, SYNTHIO_ENVELOPE_STATE_RELEASE
-} envelope_state_e;
-
 typedef struct {
     int16_t level;
     uint16_t substep;

tests/circuitpython/synthio_note_info.py

@@ -0,0 +1,17 @@
+from synthio import Synthesizer, Note, Envelope
+from audiocore import get_buffer
+
+s = Synthesizer()
+n = Note(440, envelope=Envelope())
+print("{} {:.2f}".format(*s.note_info(n)))
+s.press(n)
+print("press")
+for _ in range(9):
+    print("{} {:.2f}".format(*s.note_info(n)))
+    get_buffer(s)
+
+s.release(n)
+print("release")
+for _ in range(11):
+    print("{} {:.2f}".format(*s.note_info(n)))
+    get_buffer(s)

tests/circuitpython/synthio_note_info.py.exp

@@ -0,0 +1,23 @@
+None 0.00
+press
+synthio.NoteState.ATTACK 0.23
+synthio.NoteState.ATTACK 0.46
+synthio.NoteState.ATTACK 0.70
+synthio.NoteState.ATTACK 0.93
+synthio.NoteState.DECAY 1.00
+synthio.NoteState.DECAY 0.91
+synthio.NoteState.DECAY 0.81
+synthio.NoteState.SUSTAIN 0.80
+synthio.NoteState.SUSTAIN 0.80
+release
+synthio.NoteState.RELEASE 0.80
+synthio.NoteState.RELEASE 0.71
+synthio.NoteState.RELEASE 0.61
+synthio.NoteState.RELEASE 0.52
+synthio.NoteState.RELEASE 0.43
+synthio.NoteState.RELEASE 0.34
+synthio.NoteState.RELEASE 0.24
+synthio.NoteState.RELEASE 0.15
+synthio.NoteState.RELEASE 0.06
+synthio.NoteState.RELEASE 0.00
+None 0.00