mGBA-wasm

This package is a bundled version of my mGBA fork compiled to webassembly.

This core is framework agnostic, and can be instantiated in any framework, including vanilla javascript.

See the api documentation for in depth details.

This core currently powers gbajs3!

Install

npm i @thenick775/mgba-wasm

React

To instantiate the emulator using react:

import mGBA, { type mGBAEmulator } from '@thenick775/mgba-wasm';
import { useEffect, useState } from 'react';

export const useEmulator = (canvas: HTMLCanvasElement | null) => {
  const [emulator, setEmulator] = useState<mGBAEmulator | null>(null);

  useEffect(() => {
    const initialize = async () => {
      if (canvas) {
        const Module = await mGBA({ canvas });

        const mGBAVersion =
          Module.version.projectName + ' ' + Module.version.projectVersion;
        console.log(mGBAVersion);

        await Module.FSInit();

        setEmulator(Module);
      }
    };

    initialize();
  }, [canvas]);

  return emulator;
};

Vanilla

In a vanilla javascript project with no bundler, first download the published package tarball:

npm pack @thenick775/mgba-wasm

Extract these files from package/dist/ and serve them from the same origin as your page:

• mgba.js
• mgba.wasm

Then instantiate the emulator as follows:

<canvas id="canvas" width="240" height="160"></canvas>

<script type="module">
  import mGBA from "./mgba.js";

  const canvas = document.getElementById("canvas");
  const Module = await mGBA({ canvas });
  await Module.FSInit();

  console.log(
    `version ${Module.version.projectName + " " + Module.version.projectVersion}`,
  );
</script>

Cross-origin Isolation

This core uses threads, so the page serving these files must enable cross-origin isolation:

Cross-Origin-Opener-Policy: same-origin
Cross-Origin-Embedder-Policy: require-corp

mgba.js must be same-origin with the page because the threaded runtime starts its pthread worker from that script URL.

API

The core exposes the following contract in addition to some standard Emscripten Module utilities such as Module.FS. This is a stateful emulator runtime designed to be created once, retained by the host application, and driven through the imperative API below.

Lifecycle:

• FSInit()
• FSSync()
• pauseGame()
• resumeGame()
• pauseAudio()
• resumeAudio()
• quickReload()
• quitGame()
• quitMgba()

ROM and file management:

• loadGame(romPath, savePathOverride)
• listRoms()
• listSaves()
• filePaths()
• uploadRom(file, callback)
• uploadSaveOrSaveState(file, callback)
• uploadCheats(file, callback)
• uploadPatch(file, callback)
• uploadScreenshot(file, callback)
• uploadAutoSaveState(autoSaveStateName, data)

Input management:

• bindKey(bindingName, inputName)
• buttonPress(name)
• buttonUnpress(name)
• toggleInput(enabled)

Save data and save states:

• getSave()
• saveState(slot)
• loadState(slot)
• saveStateSlot(slot, flags)
• loadStateSlot(slot, flags)
• forceAutoSaveState()
• loadAutoSaveState()
• getAutoSaveState()

Audio, timing, and speed:

• getVolume()
• setVolume(percent)
• getMainLoopTimingMode()
• getMainLoopTimingValue()
• setMainLoopTiming(mode, value)
• getFastForwardMultiplier()
• setFastForwardMultiplier(multiplier)
• screenshot(fileName)

Callbacks and core settings:

• addCoreCallbacks(coreCallbacks)
• autoLoadCheats()
• setLogger(callback)
• setCoreSettings(coreSettings)
• toggleRewind(toggle)

Local link play:

• linkLocalStartSession(options)
• linkLocalStopSession()
• linkLocalSetActivePlayer(player)
• linkLocalGetStatus()

See dist/mgba.d.ts for full signatures and inline documentation.

Source

See the repo README for further details such as:

• building from source
• running the bundled demo
• repository and implementation details