44 lines
1.6 KiB
Python
44 lines
1.6 KiB
Python
#!/usr/bin/env python3
|
|
"""Reproduce deterministic PCM16 mono electrical discharge sounds."""
|
|
import math
|
|
import struct
|
|
import wave
|
|
from pathlib import Path
|
|
|
|
PACKAGE = "lightning_shield"
|
|
RATE = 22050
|
|
|
|
def render(kind):
|
|
heavy = PACKAGE == "lightning_cannon"
|
|
duration = (0.24 if heavy else 0.09) if kind == "fire" else (0.11 if heavy else 0.06)
|
|
count = int(RATE * duration)
|
|
seed = 0x5A17C0DE
|
|
phase = 0.0
|
|
samples = []
|
|
for n in range(count):
|
|
t = n / count
|
|
seed ^= (seed << 13) & 0xffffffff
|
|
seed ^= seed >> 17
|
|
seed ^= (seed << 5) & 0xffffffff
|
|
seed &= 0xffffffff
|
|
noise = seed / 2147483648.0 - 1.0
|
|
frequency = (2100 - 1450 * t) if heavy else (3100 - 1650 * t)
|
|
phase += 2 * math.pi * frequency / RATE
|
|
crackle = noise * (0.45 + 0.25 * math.sin(2 * math.pi * 61 * n / RATE) ** 8)
|
|
tone = math.sin(phase) * 0.24 + math.sin(phase * 1.503) * 0.15
|
|
if kind == "impact":
|
|
tone = math.sin(phase * 0.18) * 0.25
|
|
attack = min(1.0, n / (RATE * 0.002))
|
|
envelope = attack * (1 - t) ** (2.2 if kind == "fire" else 3)
|
|
samples.append(round(max(-1, min(1, (crackle + tone) * envelope)) * 21000))
|
|
return struct.pack("<" + "h" * len(samples), *samples)
|
|
|
|
if __name__ == "__main__":
|
|
output = Path(__file__).resolve().parent / "audio"
|
|
output.mkdir(exist_ok=True)
|
|
for kind in ["fire", "impact"]:
|
|
with wave.open(str(output / (kind + ".wav")), "wb") as wav:
|
|
wav.setparams((1, 2, RATE, 0, "NONE", "not compressed"))
|
|
wav.writeframes(render(kind))
|
|
print(output / (kind + ".wav"))
|