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A lightweight game engine and development platform using JavaScript for game coding, based on the original Sphere engine by Chad Austin but with a redesigned, modern API and brand-new command-line development tools.



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neoSphere: a JavaScript-based game engine


neoSphere is a lightweight, fully sandboxed, JavaScript-powered game engine and development platform. It is a complete rewrite of Chad Austin's original Sphere engine, written from the ground up in C. While neoSphere is backwards compatible with the original engine (henceforth referred to as Sphere 1.x), it also brings with it a new, modern API and a collection of powerful development tools.

Graphics and audio support are provided through Allegro 5, and JavaScript support is enabled by ChakraCore, the same JavaScript engine that once powered Microsoft Edge.


The latest release of neoSphere, complete with development tools, can always be found on the neoSphere releases page:

For an overview of the breaking changes in each release, refer to

The Sphere Toolbox

Sphere games are written in JavaScript, which gives game developers a great deal of power. The API is designed to be user-friendly and reasonably accessible to novices, allowing coders of any skill level to pick up the engine and start hacking away.

The Game Engine

The official Sphere engine implementation for desktop platforms is known as neoSphere. There is also a Web-based version, currently in development, known as Oozaru, which has its own GitHub repository but is planned to eventually be merged into the main repository.

Sphere games are written in JavaScript. The engine exposes a collection of low-level functions to the JavaScript environment, leaving higher-level game logic entirely up to script. In this way, any kind of game can be developed and you are not limited to a specific genre as in, for example, RPG Maker.

Besides the low-level Core API, there is also a set of libraries written in JavaScript that any game is free to use, collectively called the Sphere Runtime. The Runtime provides high-level functionality such as a text-based debug console and music manager, which can save a lot of time when developing new games.

The Compiler

Cell, the Sphere compiler, uses JavaScript to control the build process. Like neoSphere, Cell is powered by ChakraCore and natively supports ES2015 features like arrow functions, destructuring, and modules. A basic Cellscript might look like this:

/* Cellscript.js */

    version:  2,  // target the Sphere v2 API
    apiLevel: 3,  // require API level 3+

    name:       "My Game",
    author:     "Some Guy",
    summary:    "This game is awesome.",
    resolution: '768x480',
    main:       'scripts/main.js',

// install JavaScript modules
install('@/scripts', files('scripts/*.js', true));

// install non-code game assets
install('@/images', files('images/*.png', true));
install('@/music',  files('music/*.ogg', true));
install('@/sounds', files('sounds/*.wav', true));
install('@/',       files('icon.png'));

If that's not enough for you, then using Cell's flexible Tool API, you can extend the compiler to build any kind of asset. Simply construct a Tool object and provide a function to be called when the tool is executed. The tool below will write the contents of a single text file to the destination file:

// the second argument to `new Tool()` is optional and describes the process
// performed by the tool, e.g., "compiling" or "installing".  if omitted, Cell
// just says "building".
let copyTool = new Tool((outName, sourceNames) => {
    let text = FS.readFile(sourceNames[0]);
    FS.writeFile(outName, text);
}, "copying");

To have Cell build a file using your new tool, just do this:

// the first argument is the destination filename, the second argument is an
// array of Target objects specifying the sources.  Here we pass an exact
// filename to files() to get that array.
// note: the prefix '@/' refers to the root of the game package being compiled.
//       see `cellscript-api.txt` for more information on SphereFS prefixes.
copyTool.stage('@/eatypig.fat', files('eaty/pig.src'));

The Debugger

SSj, the Sphere debugger, is an easy-to-use command-line debugger for Sphere games. SSj works in tandem with neoSphere to allow you to step through your game's code and inspect the internal state of the code--variables, call stack, objects, etc.--while it executes. Best of all, the original source files don't need to be present: SSj can download source code directly from the engine instance being debugged.

A symbolic debugger like SSj is an invaluable tool for development and is a neoSphere exclusive: no such tool was ever available for the original engine!


The entire Sphere game development platform is licensed under the terms of the BSD-3-clause license. Practically speaking, this means the engine and tools can be used for any purpose, even commercially, with no restriction other than maintain the original copyright notice.


A lightweight game engine and development platform using JavaScript for game coding, based on the original Sphere engine by Chad Austin but with a redesigned, modern API and brand-new command-line development tools.