Improvements

This chapter is a big polish pass: event‑driven effects, wave system, radar UI, fonts, title/game‑over visuals, and collision masks.

Event bus (lib, ch13)

We add a lightweight EventBus to decouple systems. Gameplay emits events like shot:player or enemy:destroyed, and other systems react without tight coupling.

const events = new EventBus<GameEvents>();
events.emit('shot:player', { position, angle });

Beginner tip: this is “publish/subscribe.” It keeps your gameplay logic small because you don’t have to call audio or particle functions directly from every place that shoots.

Collision layers and masks

Colliders can now declare layer and mask values. The entity manager skips collision checks when masks don’t overlap. This makes it easy to prevent friendly‑fire or ignore bullets hitting bullets.

Think of layer as “what I am” and mask as “what I care about.”

Easing functions

New easing helpers (easeInSine, easeInOutQuad, etc.) are used for title pulsing and UI motion.

Easing makes motion feel natural — it starts slow, speeds up, then slows down.

AssetManager fonts

AssetManager gains queueFont() to load custom fonts via FontFace. The chapter uses Space Grotesk and updates UI text to use it consistently.

Fonts are assets too. Loading them early prevents layout jumps when the menu appears.

Radar UI

The HUD now includes a radar panel showing asteroids, enemies, and the player as tiny dots. It uses world size to map positions into the radar panel.

This is a nice example of converting world coordinates into UI coordinates.

Wave system

Enemies and asteroids are spawned in waves with a short transition overlay. Wave counts scale difficulty and score values.

Waves keep the pacing clear and give the player a moment to breathe.

Title and game‑over screens

• Animated starfield background.
• Pulsing “Press Enter” prompt using easing.
• Game‑over fade and auto return to menu after a short delay.

Library changes

• Added lib/Events (EventBus).
• Added lib/Easing.
• Extended lib/Assets with queueFont().
• Added layer and mask to colliders and filtering in EntityManager.