js-dos 8.xx Help

Node

In this tutorial we will run Digger game in Node.js and save game screenshot to the image.

Let's start with creating empty project:

npm init

To run DOS in browser we need to install emulators package. For creating screenshot we will use jimp library. So let's install them.

npm install --save emulators jimp

Next we need to download Digger js-dos bundle:

curl https://cdn.dos.zone/original/2X/2/24b00b14f118580763440ecaddcc948f8cb94f14.jsdos -o digger.jsdos

Let's create source file digger.js. We can run it with this command node digger.js

Use require to import all libraries

const fs = require("fs"); const jimp = require("jimp"); require("emulators"); const emulators = global.emulators; emulators.pathPrefix = "./";

Now we need to read contents of jsdos bundle and start emulation

const bundle = fs.readFileSync("digger.jsdos"); emulators .dosDirect(bundle) .then((ci) => { // ... });

When dos emulation starts, we will receive Command Interface, we can use it to subscribe on frame updates and to send key/mouse events.

ci.events().onFrame((rgb, rgba) => { // use rgb or rgba image data });

In the v7 we have frame in RGBA format with transparent alpha, let's fix this and save screenshot:

const width = ci.width(); const height = ci.height(); for (let next = 3; next < width * height * 4; next = next + 4) { rgba[next] = 255; } new jimp({ data: rgba, width, height }, (err, image) => { image.write("./screenshot.png", () => { ci.exit(); }); });

If you execute node digger.js it will save the screenshot to ./screenshot.png.

Full code of digger.js:

const fs = require("fs"); const jimp = require("jimp"); require("emulators"); const emulators = global.emulators; emulators.pathPrefix = "./"; const bundle = fs.readFileSync("digger.jsdos"); emulators .dosDirect(bundle) .then((ci) => { let rgba = new Uint8Array(0); ci.events().onFrame((_, _rgba) => { rgba = _rgba; }); // capture the screen after 3 sec console.log("Will capture screen after 3 sec..."); setTimeout(() => { const width = ci.width(); const height = ci.height(); for (let next = 3; next < width * height * 4; next = next + 4) { rgba[next] = 255; } new jimp({ data: rgba, width, height }, (err, image) => { image.write("./screenshot.png", () => { ci.exit(); }); }); }, 3000); }) .catch(console.error);
Last modified: 26 апреля 2024