Add monophonic Audio FX

circuitpython-audio-fx/monophonic/code.py

@@ -0,0 +1,230 @@
+# SPDX-FileCopyrightText: Copyright 2024 Jeff Epler for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+# pylint: disable=no-self-use
+
+import os
+import io
+import random
+
+import board
+import digitalio
+import keypad
+import audiobusio
+import audiocore
+import audiomp3
+
+# Configure the pins to use -- earlier in list = higher priority
+pads = [
+    board.GP0, board.GP1, board.GP2, board.GP3,
+    board.GP4, board.GP5, board.GP6, board.GP7,
+    board.GP8, board.GP9, board.GP10, board.GP11,
+    board.GP12, board.GP13, board.GP14, board.GP15
+]
+
+# Configure the audio device
+audiodev = audiobusio.I2SOut(
+    bit_clock=board.GP16, word_select=board.GP17, data=board.GP18
+)
+
+led = digitalio.DigitalInOut(board.LED)
+led.switch_to_output(False)
+
+# This is enough to register as an MP3 file with mp3decoder!, allows creating a decoder
+# without "opening" a "file"!
+EMPTY_MP3_BYTES = b"\xff\xe3"
+
+# Create the MP3 decoder object
+decoder = audiomp3.MP3Decoder(io.BytesIO(EMPTY_MP3_BYTES))
+
+def exists(p):
+    try:
+        os.stat(p)
+        return True
+    except OSError:
+        return False
+
+
+def random_shuffle(seq):
+    for i in range(len(seq)):
+        j = random.randrange(0, i+1)
+        if i != j: # Chance an item remains in same location
+            seq[i], seq[j] = seq[j], seq[i]
+
+def random_cycle(seq):
+    while True:
+        random_shuffle(seq)
+        yield from seq
+
+def cycle(seq):
+    while True:
+        yield from seq
+
+class TriggerBase:
+    def __init__(self, prefix):
+        self._filenames = list(self._gather_filenames(prefix))
+        self._filename_generator = type(self).generate_filenames(self._filenames)
+        self.wants_to_play = False
+
+    # Can be cycle or random_cycle
+    generate_filenames = cycle
+
+    def on_press(self):
+        self.wants_to_play = True
+
+    def on_release(self):
+        self.wants_to_play = False
+
+    def on_activate(self):
+        self.play_wait()
+
+    def _gather_filenames(self, prefix):
+        if self.stems is None:
+            return
+        for stem in self.stems:
+            name_mp3 = f"{prefix}{stem}.mp3"
+            if exists(name_mp3):
+                yield name_mp3
+                continue
+            name_wav = f"{prefix}{stem}.wav"
+            if exists(name_wav):
+                yield name_wav
+                continue
+
+    def _get_sample(self, path):
+        if path.endswith(".mp3"):
+            decoder.open(path)
+            return decoder
+        else:
+            return audiocore.WaveFile(path)
+
+    def play(self, loop=False):
+        audiodev.stop()
+        path = next(self._filename_generator)
+        sample = self._get_sample(path)
+        audiodev.play(sample, loop=loop)
+
+    def play_wait(self):
+        self.play()
+        while audiodev.playing:
+            poll_keys()
+
+    def stop(self):
+        audiodev.stop()
+
+    @classmethod
+    def matches(cls, prefix):
+        stem = cls.stems[0]
+        name_mp3 = f"{prefix}{stem}.mp3"
+        name_wav = f"{prefix}{stem}.wav"
+        return exists(name_wav) or exists(name_mp3)
+
+    def __repr__(self):
+        return (f"<{self.__class__.__name__} {' '.join(self._filenames)}" +
+                f"{' ACTIVE' if self.wants_to_play else ''}>")
+
+
+class NopTrigger(TriggerBase):
+    """Does nothing."""
+
+    stems = None
+
+    def on_activate(self):
+        return
+
+class BasicTrigger(TriggerBase):
+    """Plays a file each time the button is pressed down"""
+
+    stems = [""]
+
+class HoldLoopingTrigger(TriggerBase):
+    """Plays a file as long as a button is held down
+
+    This differs from the basic trigger because the loop stops as soon as the button
+    is released """
+
+    stems = ["HOLDL"]
+
+    def on_activate(self):
+        self.play(loop=True)
+        while audiodev.playing:
+            poll_keys()
+            for trigger in triggers:
+                if trigger is self:
+                    break
+                if trigger.wants_to_play:
+                    self.wants_to_play = False
+            if not self.wants_to_play:
+                audiodev.stop()
+
+class LatchingLoopTrigger(HoldLoopingTrigger):
+    """Plays a file until the button is pressed again
+
+    When the button is pressed again, stops the loop immediately."""
+
+    stems = ["LATCH"]
+
+    def on_press(self):
+        if self.wants_to_play or not audiodev.playing:
+            self.wants_to_play = not self.wants_to_play
+
+    def on_release(self):
+        pass # override default behavior
+
+
+class PlayNextTrigger(TriggerBase):
+    stems = [f"NEXT{i}" for i in range(10)]
+    _phase = 0
+
+
+class PlayRandomTrigger(TriggerBase):
+    stems = [f"RAND{i}" for i in range(10)]
+
+    generate_filenames = random_cycle
+
+
+
+trigger_classes = [
+    BasicTrigger,
+    HoldLoopingTrigger,
+    LatchingLoopTrigger,
+    PlayNextTrigger,
+    PlayRandomTrigger,
+]
+
+
+def make_trigger(i):
+    prefix = f"T{i:02d}"
+
+    for cls in trigger_classes:
+        if not cls.matches(prefix):
+            continue
+        return cls(prefix)
+
+    return NopTrigger(prefix)
+
+
+keys = keypad.Keys(pads, value_when_pressed=False)
+
+triggers = [make_trigger(i) for i in range(len(pads))]
+
+def poll_keys():
+    while e := keys.events.get():
+        trigger = triggers[e.key_number]
+        if e.pressed:
+            trigger.on_press()
+        else:
+            trigger.on_release()
+        print(e.pressed, trigger)
+
+print(triggers)
+
+reversed_triggers = list(reversed(triggers))
+
+while True:
+    poll_keys()
+    for t in triggers:
+        if t.wants_to_play:
+            print(t)
+            t.on_activate()
+            break