settled-reach/tooling/synth_ui_sounds.py

#!/usr/bin/env python3
"""Synthesize insert-tech UI sounds for Sprint 7 #440.

Each sound uses a DIFFERENT synthesis technique to ensure distinct character:
- cursor_hover: impulse → resonant bandpass (digital click)
- weapon_aim: filtered noise + sub thump (mechanical)
- monologue_chime: FM synthesis (crystalline bell)
- monologue_chime_urgent: FM synthesis + beating/dissonance (tense bell)
"""

import numpy as np
import wave
import os

SR = 44100
OUTPUT_DIR = os.path.join(os.path.dirname(__file__), "..", "client", "assets", "audio")


def write_wav(filename, samples, channels=1):
    """Write float samples [-1, 1] to 16-bit WAV."""
    path = os.path.join(OUTPUT_DIR, filename)
    # Normalize to peak if it exceeds 1.0
    peak = np.max(np.abs(samples))
    if peak > 1.0:
        samples = samples / peak
    int_samples = np.clip(samples * 32767, -32767, 32767).astype(np.int16)
    with wave.open(path, "w") as f:
        f.setnchannels(channels)
        f.setsampwidth(2)
        f.setframerate(SR)
        f.writeframes(int_samples.tobytes())
    dur_ms = len(int_samples) / SR * 1000
    print(f"  wrote {path} ({dur_ms:.0f}ms, {channels}ch)")
    return path


def simple_lowpass(signal, cutoff_hz, sr=SR):
    """Single-pole IIR low-pass filter."""
    rc = 1.0 / (2 * np.pi * cutoff_hz)
    dt = 1.0 / sr
    alpha = dt / (rc + dt)
    out = np.zeros_like(signal)
    out[0] = alpha * signal[0]
    for i in range(1, len(signal)):
        out[i] = out[i - 1] + alpha * (signal[i] - out[i - 1])
    return out


def simple_highpass(signal, cutoff_hz, sr=SR):
    """Single-pole IIR high-pass filter."""
    rc = 1.0 / (2 * np.pi * cutoff_hz)
    dt = 1.0 / sr
    alpha = rc / (rc + dt)
    out = np.zeros_like(signal)
    out[0] = signal[0]
    for i in range(1, len(signal)):
        out[i] = alpha * (out[i - 1] + signal[i] - signal[i - 1])
    return out


def cursor_hover():
    """UI-001: Digital click/tick on entity hover.

    Technique: Short noise impulse bandpass-filtered to ~4kHz.
    Sounds like a tiny digital snap — no sustained tone at all.
    The "click" of a selection appearing on a HUD.
    """
    duration = 0.035  # 35ms — shorter than before
    n = int(SR * duration)
    t = np.linspace(0, duration, n, endpoint=False)
    rng = np.random.default_rng(77)

    # White noise impulse
    impulse = rng.uniform(-1, 1, n)

    # Bandpass around 4kHz: high-pass at 3kHz, low-pass at 5kHz
    filtered = simple_highpass(impulse, 3000)
    filtered = simple_lowpass(filtered, 5500)

    # Very fast decay — done in 25ms
    envelope = np.exp(-t * 140)

    return write_wav("cursor_hover.wav", filtered * envelope * 0.3)


def weapon_aim():
    """UI-004: Mechanical latch for weapon aim.

    Technique: Low-pass filtered noise burst (the clack) + sub-bass
    thump (the weight). No musical pitch — this is a MECHANICAL sound.
    Think: safety clicking off, bolt sliding home.
    """
    duration = 0.15  # 150ms
    n = int(SR * duration)
    t = np.linspace(0, duration, n, endpoint=False)
    rng = np.random.default_rng(42)

    # Component 1: Low-pass noise burst — the metallic clack
    noise = rng.uniform(-1, 1, n)
    # Low-pass at 1.5kHz — dull, heavy impact, not bright
    clack = simple_lowpass(noise, 1500)
    clack_env = np.exp(-t * 60)  # fast decay
    clack = clack * clack_env

    # Component 2: Sub-bass thump — weight of the mechanism
    # 80Hz sine, very fast decay
    thump = np.sin(2 * np.pi * 80 * t)
    thump_env = np.exp(-t * 40)
    thump = thump * thump_env

    # Component 3: High metallic click at the very start (2ms)
    click = rng.uniform(-1, 1, n)
    click = simple_highpass(click, 4000)
    click_env = np.zeros(n)
    click_mask = t < 0.003
    click_env[click_mask] = np.exp(-t[click_mask] * 800)
    click = click * click_env

    signal = clack * 0.4 + thump * 0.35 + click * 0.25
    return write_wav("weapon_aim.wav", signal * 0.45)


def monologue_chime():
    """UI-005: Crystalline thought-chime. PLACEHOLDER.

    Technique: FM synthesis — carrier modulated by a lower frequency
    creates rich, evolving harmonics that sound like struck glass or
    crystal. Fundamentally different timbre from additive sine waves.
    """
    duration = 0.75  # 750ms
    n = int(SR * duration)
    t = np.linspace(0, duration, n, endpoint=False)

    # FM synthesis: carrier at 1200Hz, modulator at 420Hz (ratio ~2.86:1)
    # Inharmonic ratio = bell-like quality
    f_carrier = 1200
    f_mod = 420
    # Mod index decays over time — bright attack, mellow sustain
    mod_index = 3.0 * np.exp(-t * 6)
    # Modulator signal
    modulator = mod_index * np.sin(2 * np.pi * f_mod * t)
    # Carrier with FM
    signal = np.sin(2 * np.pi * f_carrier * t + modulator)

    # Gentle attack (20ms), slow decay
    attack = np.minimum(t / 0.02, 1.0)
    decay = np.exp(-t * 3.0)
    envelope = attack * decay

    return write_wav("sfx_monologue_chime.wav", signal * envelope * 0.22)


def monologue_chime_urgent():
    """UI-006: Urgent thought-chime. PLACEHOLDER.

    Technique: FM synthesis with higher mod index (brighter/harsher) +
    a second detuned carrier that creates beating/tension. The beating
    is what makes it feel "urgent" — not louder, but unsettled.
    """
    duration = 0.5  # 500ms — shorter
    n = int(SR * duration)
    t = np.linspace(0, duration, n, endpoint=False)

    f_carrier = 1200
    f_mod = 420

    # Higher mod index = more sidebands = brighter, more aggressive
    mod_index = 5.0 * np.exp(-t * 7)
    modulator = mod_index * np.sin(2 * np.pi * f_mod * t)

    # Primary carrier
    carrier1 = np.sin(2 * np.pi * f_carrier * t + modulator)

    # Second carrier, detuned +8Hz — creates beating at 8Hz (nervous flicker)
    carrier2 = np.sin(2 * np.pi * (f_carrier + 8) * t + modulator * 0.8)

    signal = carrier1 * 0.6 + carrier2 * 0.4

    # Sharp attack (6ms), faster decay
    attack = np.minimum(t / 0.006, 1.0)
    decay = np.exp(-t * 4.0)
    envelope = attack * decay

    # 15% louder than normal
    return write_wav("sfx_monologue_chime_urgent.wav", signal * envelope * 0.25)


if __name__ == "__main__":
    os.makedirs(OUTPUT_DIR, exist_ok=True)
    print("Synthesizing UI sounds for Sprint 7 #440...")
    print()

    print("[UI-001] cursor_hover — bandpass noise impulse (digital click)")
    cursor_hover()

    print("[UI-004] weapon_aim — filtered noise + sub thump (mechanical latch)")
    weapon_aim()

    print("[UI-005] sfx_monologue_chime — FM synthesis bell (PLACEHOLDER)")
    monologue_chime()

    print("[UI-006] sfx_monologue_chime_urgent — FM + beating (PLACEHOLDER)")
    monologue_chime_urgent()

    print()
    print("Done. Convert with: tooling/db/audio-post convert <file.wav>")