LittleJS - The Tiny JavaScript Game Engine That Can

🚂 All aboard!

LittleJS is a lightweight open source HTML5 game engine designed for modern web development. It's small footprint is packed with a comprehensive feature set, including hybrid rendering, physics, particles, sound effects, music, input handling, and debug tools. The code is very clean and well documented with some fun examples to get you started. Choo-Choo! 🚂

Demo | Docs | Trailer | Discord | Tutorial

About LittleJS

LittleJS is a small but powerful game engine with many features and no dependencies.

✨ Graphics

• Super fast sprite and tile map rendering engine with WebGL
• Update and render over 10,000 objects at a solid 60fps
• Apply Shadertoy compatible shaders for post processinge effects
• Robust particle effect system and effect design tool

🔊 Audio

• Positional sound effects with wave or ZzFX
• Music with mp3, ogg, wave, or ZzFXM

🎮 Input

• Comprehensive system for keyboard, mouse, gamepad, and touch
• On screen touch gamepad designed for mobile devices

💥 Physics

• 2D physics engine with collision handling for axis aligned boxes
• Very fast collision and raycasting for tile maps

🚀 Flexability

• Compatible with all modern web bowsers and on mobile devices
• Support for TypeScript and Modules with example projects for both
• Ideal for size coding competitions like js13kGames, starter project builds to a 7KB zip
• Builds to an executable with Electron for distribution on Windows, macOS, and Linux
• Open Source with the MIT license so it can be used for anything you want forever

🛠️ And more...

• Node.js build system
• 2D vector math library
• Debug primitive rendering system
• Particle effects system and design tool
• Bitmap font rendering and includes a built in engine font
• Medal system tracks and displays achievements with Newgrounds integration

Demos

Starter Project - Clean example with only a few things to get you started

Breakout - Breakout game with post processing effect

Puzzle Game - Match 3 puzzle game with HD rendering and high score tracking

Platformer - Platformer/shooter with procedural generation and destruction

Stress Test - Max sprite/object test and music system demo

Particle System Designer - Particle system editor and visualizer

How to use LittleJS

To use LittleJS download the latest package from GitHub or call npm install littlejsengine.

The Breakout Tutorial demonstrates how to make a simple game from scratch. The tutorial is also available on YouTube.

This GitNation talk explains how LittleJS works with some tips on how to use it.

Builds

To easily include LittleJS in your game, you can use one of the pre-built js files.

• littlejs.js - The full game engine with debug mode available
• littlejs.release.js - The engine optimized for release builds
• littlejs.min.js - The engine in release mode and minified
• littlejs.esm.js - The engine exported as a module with debug mode available
• littlejs.esm.min.js - The engine exported as a minified module in release mode

To rebuild the engine you must first run npm install to setup the necessary npm dependencies. Then call npm run build to build the engine.

The starter example project includes a node js file build.js that compresses everything into a tiny zip file using Google Closure, UglifyJS, and ECT Zip.

LittleJS Setup

To start LittleJS, you need to create these 5 functions and pass them to engineInit.

function gameInit()
{
    // called once after the engine starts up
    // setup the game
}

function gameUpdate()
{
    // called every frame at 60 frames per second
    // handle input and update the game state
}

function gameUpdatePost()
{
    // called after physics and objects are updated
    // setup camera and prepare for render
}

function gameRender()
{
    // called before objects are rendered
    // draw any background effects that appear behind objects
}

function gameRenderPost()
{
    // called after objects are rendered
    // draw effects or hud that appear above all objects
}

// Startup LittleJS Engine
engineInit(gameInit, gameUpdate, gameUpdatePost, gameRender, gameRenderPost);

LittleJS Objects

LittleJS can be used as an object oriented system by extending the base class EngineObject with your own. This lightweight class provides many useful features including physics, collision, parent/child system, and sorted rendering. These objects are added to the global list of objects where they will automatically be updated and rendered until destroyed.

Here is a template you can use to make objects that behave however you want. See the examples for a complete demonstration.

class MyObject extends EngineObject 
{
    constructor(pos, size, tileInfo, angle)
    {
        super(pos, size, tileInfo, angle);
        // setup object
    }

    update()
    {
        // update object physics and position
        super.update(); 
    }

    render()
    {
        // draw object as a sprite
        super.render();
    }
}

Debugging

Debug builds of LittleJS have a special menu that can be opened by pressing the Esc key.

• Esc: Debug Overlay
• 1: Debug Physics
• 2: Debug Particles
• 3: Debug Gamepads
• 4: Debug Raycasts
• 5: Save Screenshot

Games Made With LittleJS

Here are a few of the amazing games people are making with LittleJS...

• Space Huggers - Run and gun platformer with procedural levels
• Undergrowth - An interactive music videogame for the band Squid
• Space Huggers - JS13K Edition - Original js13k game with source code
• Isletopia - Relaxing strategy game of greenifying barren islands
• Dead Again - Top down survial horror by sanojian & repsej
• Hel's Trial - Turn based RPG by Sebastian Dorn
• Bit Butcher - Survival crafting game by Deathray Games
• Necrotic Commander - Tower defense game by Daniel Jeffery
• Boxing up Bamboo - A challenging puzzle game by Patrick Traynor
• Samurai Sam - A Fruit Ninja inspired game by John Edvard