Sound

This chapter adds audio. We extend the asset manager to queue sounds, introduce an AudioManager, and wire up SFX + background music.

AudioManager (lib, ch11)

The audio system wraps the Web Audio API:

• loadSound(key, src) decodes a sound into an AudioBuffer.
• registerSound(key, buffer) stores a buffer (useful with the asset loader).
• playSound(key, volume) plays one‑shot effects.
• playMusic(key, volume) loops a track and keeps a handle for volume/stop.

Why use Web Audio?

Web Audio gives reliable timing and volume control, which is important for responsive gameplay sounds. It also lets us mix multiple sounds without managing <audio> tags.

AssetManager changes

AssetManager now supports queued tasks and sounds:

• queueSound(key, src, ctx) adds a sound task using an AudioContext.
• loadAll() reports progress across images and tasks.
• getSound(key) retrieves the decoded buffer.

This keeps audio loading in the same pipeline as images.

Beginner tip: by treating sounds like assets, you avoid “missing sound” bugs the same way you avoid “missing sprite” bugs.

Wiring audio in the game

In the loading state:

• queue music tracks and SFX.
• load all assets.
• register the decoded buffers with AudioManager.

When the player starts the game, AudioManager.resume() is called after user input to satisfy browser autoplay rules.

If you try to play audio before a user gesture, most browsers will block it. Calling resume() after pressing Enter unlocks audio playback.

Gameplay audio

• Laser shots play on fire.
• Enemy shots play when enemies shoot.
• Explosions play on asteroid and enemy destruction.
• Music changes between menu and gameplay.

This makes the game feel more alive and gives feedback for actions.

Library changes

• Added lib/Audio.
• Extended lib/Assets to support sound queues and typed progress.