Serverboy

Serverboy is a pure NodeJS headless Gameboy emulator with hooks for scripting and streaming output, adapted for use by Piglet.

Serverboy has no dependencies, including browser-side dependencies like Canvas. This makes Serverboy ideal for headless streaming and scripting via low-powered environments and environments where users are not able to install additional software dependencies like Cairo.

Unlike most emulators, Serverboy's API is heavily geared towards automation and serverside projects. Serverboy doesn't auto-advance frames, so you can step forward frame by frame after running asynchronous logic. Serverboy also provides hooks for getting raw memory access, raw screen pixels, and raw PCM audio data.

This focus on automation means that Serverboy is not generally suited for regular play. There's no integrated code for displaying the screen or playing audio. It's designed to be used inside other more experimental projects. If you just want a way to play games, look elsewhere unless you're willing to build your own front-end.

Serverboy is alpha software; elements like sound are still a work in progress. The API may change over time.

Usage

The full API is available in the docs.

var gameboy = new Gameboy();
var rom = fs.readFileSync(file_path);

gameboy.loadRom(rom);

setTimeout(function () {

   //Whatever custom logic you need
   var memory = gameboy.getMemory();
   if (memory[3000] === 0) {
       gameboy.pressKeys([Gameboy.KEYMAP.RIGHT]);
   }
   
   gameboy.doFrame();
}, 0);

Integration Tests

Serverboy uses Blargg's Test Roms for integration tests to ensure that simulation accuracy doesn't change during code refactoring.

Serverboy doesn't guarantee complete emulation accuracy, just consistency with the results below. More tests and accuracy changes may be added in the future.

Credits

Serverboy is heavily based on work by rauchg, which is itself heavily based on Grant Galitz's earlier work with Gameboy Online. Most of this code originated in Grant's repo, and I've mostly been playing janitor since.

Imran Nazar's article series, Gameboy Emulation in Javascript was also an occasional help when I wanted dig into the internals of how the hardware actually worked to help with refactoring.