synthio: add a noise program to the manual tests

tests/circuitpython-manual/synthio/note/noise.py

@@ -0,0 +1,71 @@
+import sys
+
+sys.path.insert(
+    0, f"{__file__.rpartition('/')[0] or '.'}/../../../../frozen/Adafruit_CircuitPython_Wave"
+)
+
+import random
+import audiocore
+import synthio
+from ulab import numpy as np
+import adafruit_wave as wave
+
+random.seed(9)
+SAMPLE_SIZE = 1024
+VOLUME = 14700
+noise = np.array(
+    [random.randint(-32768, 32767) for i in range(SAMPLE_SIZE)],
+    dtype=np.int16,
+)
+
+envelope = synthio.Envelope(
+    attack_time=0,
+    decay_time=0.2,
+    sustain_level=0,
+)
+
+synth = synthio.Synthesizer(sample_rate=48000)
+
+
+def randf(lo, hi):
+    return random.random() * (hi - lo) + lo
+
+
+def synthesize(synth):
+    notes = [
+        synthio.Note(
+            frequency=synthio.midi_to_hz(1 + i),
+            waveform=noise,
+            envelope=envelope,
+            bend_mode=synthio.BendType.SWEEP,
+            bend_depth=random.choice((-1, 1)),
+            bend_rate=randf(4, 12),
+        )
+        for i in range(12)
+    ]
+
+    random.seed(9)
+    for _ in range(16):
+        n = random.choice(notes)
+        d = random.randint(30, 60)
+        print(n, d)
+        synth.press((n,))
+        yield d
+    synth.release_all()
+    yield 36
+
+
+def chain(*args):
+    for a in args:
+        yield from a
+
+
+# sox -r 48000 -e signed -b 16 -c 1 tune.raw tune.wav
+with wave.open("noise.wav", "w") as f:
+    f.setnchannels(1)
+    f.setsampwidth(2)
+    f.setframerate(48000)
+    for n in chain(synthesize(synth)):
+        for i in range(n):
+            result, data = audiocore.get_buffer(synth)
+            f.writeframes(data)