# sfx-maker (`sfxc`)

Synthesizes **retro game sound effects** (sfxr-style) from `.sfx` text
files and writes 16-bit mono **WAV**. Sound design becomes text an agent
can read, tweak and reason about — no DAW needed. Go, zero
dependencies, single static binary.

## Build

```bash
# Arch/Garuda: sudo pacman -S go
cd sfx-maker
go build -o build/sfxc .        # or the VS Code task "build sfx-maker"
go test ./...
```

## Quick start

```bash
sfxc preset jump -o jump.sfx      # editable text preset
sfxc build jump.sfx               # -> jump.wav
mpv jump.wav                      # listen (or aplay/ffplay)

sfxc preset coin -o coin.wav      # straight to WAV
sfxc preset coin --seed 3 -o coin3.wav    # deterministic variant
sfxc info laser.sfx               # validate + summary
```

Presets: `blip, coin, explosion, hurt, jump, laser, powerup`.
`--seed 0` is the canonical sound; any other seed nudges pitch/length
deterministically — ask for three seeds, keep the one that sounds best.

## The `.sfx` format

```
# comment
sfx: jump            name
wave: square         square | saw | sine | triangle | noise
volume: 0.7          0..1
attack: 0.01         seconds: fade in
sustain: 0.08        hold at full volume
decay: 0.18          fade out (total length = a+s+d, max 10 s)
freq: 330            start pitch, Hz
freq-slide: 900      Hz/second (positive = rising, negative = falling)
duty: 0.5            square pulse width 0.05..0.95 (thinner = buzzier)
vibrato-depth: 25    pitch wobble, Hz
vibrato-rate: 9      wobbles per second
arpeggio: 1.335      multiply pitch by this...
arpeggio-time: 0.06  ...after this many seconds (classic coin blip)
lowpass: 2200        cutoff Hz (muffle: explosions, thuds)
highpass: 300        cutoff Hz (thin out: lasers, clicks)
sample-rate: 44100   8000-96000
seed: 1              noise randomness — same seed = same sound
```

Unknown keys are **errors**, so typos surface immediately. Everything is
deterministic: same file → byte-identical WAV.

## Recipe intuition for agents

- **Jump**: square wave + rising `freq-slide`.
- **Coin/pickup**: square + `arpeggio` > 1 shortly after the start.
- **Laser**: saw + steep negative `freq-slide` + `highpass`.
- **Explosion**: noise + `lowpass` ~2 kHz + long `decay`.
- **Hurt**: saw, low pitch, quick fall.
- **Power-up**: rising slide + `vibrato`.

[`examples/`](examples/) contains all presets as `.sfx` + rendered `.wav`.