chongdashu Phaser Game Development
Build 2D browser games using Phaser 3's scene-based architecture and physics systems.
STOP: Before Loading Any Spritesheet
Read spritesheets-nineslice.md FIRST.
Spritesheet loading is fragile—a few pixels off causes silent corruption that compounds into broken visuals. The reference file contains the mandatory inspection protocol.
Quick rules (details in reference):
- Measure the asset before writing loader code—never guess frame dimensions
- Character sprites use SQUARE frames: If you calculate frameWidth=56, try 56 for height first
- Different animations have different frame sizes: A run cycle needs wider frames than idle; an attack needs extra width for weapon swing. Measure EACH spritesheet independently
- Check for spacing: Gaps between frames require
spacing: Nin loader config - Verify the math:
imageWidth = (frameWidth × cols) + (spacing × (cols - 1))
Reference Files
Read these BEFORE working on the relevant feature:
| When working on... | Read first |
|---|---|
| Loading ANY spritesheet | spritesheets-nineslice.md |
| Nine-slice UI panels | spritesheets-nineslice.md |
| Tiled tilemaps, collision layers | tilemaps.md |
| Physics tuning, groups, pooling | arcade-physics.md |
| Performance issues, object pooling | performance.md |
Architecture Decisions (Make Early)
Physics System Choice
| System | Use When |
|---|---|
| Arcade | Platformers, shooters, most 2D games. Fast AABB collisions |
| Matter | Physics puzzles, ragdolls, realistic collisions. Slower, more accurate |
| None | Menu scenes, visual novels, card games |
Scene Structure
scenes/
├── BootScene.ts # Asset loading, progress bar
├── MenuScene.ts # Title screen, options
├── GameScene.ts # Main gameplay
├── UIScene.ts # HUD overlay (launched parallel)
└── GameOverScene.ts # End screen, restart
Scene Transitions
this.scene.start('GameScene', { level: 1 }); // Stop current, start new
this.scene.launch('UIScene'); // Run in parallel
this.scene.pause('GameScene'); // Pause
this.scene.stop('UIScene'); // Stop
Core Patterns
Game Configuration
const config: Phaser.Types.Core.GameConfig = {
type: Phaser.AUTO,
width: 800,
height: 600,
scale: {
mode: Phaser.Scale.FIT,
autoCenter: Phaser.Scale.CENTER_BOTH
},
physics: {
default: 'arcade',
arcade: { gravity: { y: 300 }, debug: false }
},
scene: [BootScene, MenuScene, GameScene]
};
Scene Lifecycle
class GameScene extends Phaser.Scene {
init(data) { } // Receive data from previous scene
preload() { } // Load assets (runs before create)
create() { } // Set up game objects, physics, input
update(time, delta) { } // Game loop, use delta for frame-rate independence
}
Frame-Rate Independent Movement
// CORRECT: scales with frame rate
this.player.x += this.speed * (delta / 1000);
// WRONG: varies with frame rate
this.player.x += this.speed;
Anti-Patterns
| Anti-Pattern | Problem | Solution |
|---|---|---|
Global state on window |
Scene transitions break state | Use scene data, registries |
Loading in create() |
Assets not ready when referenced | Load in preload(), use Boot scene |
| Frame counting | Game speed varies with FPS | Use delta / 1000 |
| Matter for simple collisions | Unnecessary complexity | Arcade handles most 2D games |
| One giant scene | Hard to extend | Separate gameplay/UI/menus |
| Magic numbers | Impossible to balance | Config objects, constants |
| No object pooling | GC stutters | Groups with setActive(false) |
Remember
Phaser provides powerful primitives—scenes, sprites, physics, input—but architecture is your responsibility.
Before coding: What scenes? What entities? How do they interact? What physics model?
Claude can build complete, polished Phaser games. These guidelines illuminate the path—they don't fence it.