Play it now.

Bryan Braun gave us Checkboxland, a unique library for rendering text, shapes, and video, via a grid of checkboxes.

Id software gave us DOOM.

Cornelius Diekmann gave us DOOM via WebAssembly.

Healey gave us DOOM via Checkboxes.

Today, I'm pleased to stand on top of these giants' shoulders, and give you DOOM via Console.log().

DOOM runs via WebAssembly in a hidden <canvas>. I use HTMLCanvasElement.toDataURL() to turn this into a base64 encoded string. A Console.log() is called with two arguments, "%c X", which is a random string that is going to be stylized by the next parameter, which is composed of css properties. I then attribute the base 64 into a background-url property, thus rendering it.

const base64Image = canvas.toDataURL().replace(/(\r\n|\n|\r)/gm, "");
console.log(
  "%c X",
  `font-size:400px;color: transparent;background:url(${base64Image}) no-repeat; background-size: contain;margin-top: 140px;margin-left: 60px;`
);

Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user.

Key events are forwarded to the hidden <canvas> to avoid focus issues.

const forwardKey = (e, type) => {
  const ev = new KeyboardEvent(type, {
    key: e.key,
    keyCode: e.keyCode,
  });
  canvas.dispatchEvent(ev);
};
document.body.addEventListener("keydown", (e) => forwardKey(e, "keydown"));
document.body.addEventListener("keyup", (e) => forwardKey(e, "keyup"));

While the .wasm is downloaded and processed, the console displays a loading message.

python dev.py

Edit files, refresh.