Tiny Game Engine 🎮

A minimalist 2D game engine optimized for JS13K competitions.

Target size: < 2KB gzipped (leaving ~11KB for your game code)

Features

- ✅ Fixed timestep game loop (60 FPS)
- ✅ Entity system with velocity/acceleration
- ✅ Sprite rendering (rect, image, animation)
- ✅ Unified keyboard + pointer input
- ✅ Collision detection (AABB, circle, circle-rect)
- ✅ Object pooling for particles/bullets
- ✅ Zero dependencies
- ✅ Tree-shakeable exports

Installation

``bash
bun add tiny-game-engine
`

Quick Start

`js
import { init, loop, sprite, initInput, keyDown, clamp } from 'tiny-game-engine'

let { canvas, ctx } = init('game')
initInput(canvas)

let player = sprite({
x: 100,
y: 100,
width: 32,
height: 32,
color: '#e94560'
})

loop({
update(dt) {
if (keyDown('left')) player.x -= 200 * dt
if (keyDown('right')) player.x += 200 * dt
if (keyDown('up')) player.y -= 200 * dt
if (keyDown('down')) player.y += 200 * dt

player.x = clamp(0, canvas.width - 32, player.x)
player.y = clamp(0, canvas.height - 32, player.y)
},
render() {
player.render(ctx)
}
}).start(ctx)
`

API

$3

`js
import { init, getCtx, getCanvas } from 'tiny-game-engine'

let { canvas, ctx } = init('canvas-id') // or pass canvas element
`

$3

`js
import { loop } from 'tiny-game-engine'

let gameLoop = loop({
fps: 60, // target framerate (default: 60)
clear: true, // auto-clear canvas (default: true)
update(dt) {}, // called at fixed timestep
render() {} // called every frame
})

gameLoop.start(ctx)
gameLoop.stop()
`

$3

`js
import { vec, add, sub, scale, len, norm, dot, dist } from 'tiny-game-engine'

let v = vec(3, 4)
let length = len(v) // 5
let normalized = norm(v) // { x: 0.6, y: 0.8 }

// Zero-allocation in hot paths
let out = vec()
add(a, b, out) // result stored in out
`

$3

`js
import { entity, sprite } from 'tiny-game-engine'

// Base entity (no rendering)
let e = entity({
x: 0, y: 0,
dx: 10, dy: 0, // velocity
ddx: 0, ddy: 9.8, // acceleration
ttl: 5 // time to live (seconds)
})

// Sprite (renderable entity)
let s = sprite({
x: 100, y: 100,
width: 32, height: 32,
color: '#ff0000',
anchor: { x: 0.5, y: 0.5 },
opacity: 0.8,
rotation: Math.PI / 4
})
`

$3

`js
import { initInput, keyDown, getPointer, pointerDown } from 'tiny-game-engine'

initInput(canvas)

// In update loop
if (keyDown('left')) { / ... / }
if (keyDown('a')) { / ... / }
if (keyDown('space')) { / ... / }

let { x, y } = getPointer()
if (pointerDown()) { / ... / }
`

$3

`js
import { aabb, circle, circleRect, pointRect, pointCircle } from 'tiny-game-engine'

if (aabb(player, enemy)) { / collision! / }
if (circle(bullet, target)) { / collision! / }
`

$3

`js
import { pool, sprite } from 'tiny-game-engine'

let bullets = pool(() => sprite({
width: 4, height: 4,
color: '#fff',
ttl: 2
}))

// Get bullet from pool
let bullet = bullets.get({ x: player.x, y: player.y, dy: -300 })

// In game loop
bullets.update(dt) // auto-releases dead bullets
bullets.render(ctx)
`

$3

`js
import { lerp, clamp, degToRad, radToDeg, rand, randInt, pick } from 'tiny-game-engine'

lerp(0, 100, 0.5) // 50
clamp(0, 100, 150) // 100
degToRad(90) // 1.5707...
rand(10, 20) // random float 10-20
randInt(1, 6) // random int 1-6
pick(['a', 'b', 'c']) // random element
`

$3

`js
import { on, off, emit, once } from 'tiny-game-engine'

on('score', points => console.log(+${points}))
emit('score', 100)

once('gameover', () => { / called once / })
`

Development

`bash
bun run dev # Start dev server with HMR
bun run build # Bundle for production
bun run test # Run tests
bun run size # Check bundle size
``

License

MIT