Show HN: I recreated 90s Mode X demoscene effects in JavaScript and Canvas

After 25 years of writing software, I was feeling nostalgic for the kinds of things that got me into programming in the first place: the old DOS demoscene. I spent a weekend seeing if I could recapture some of that INT 13H VGA magic using today's web tech, but with the old-school constraints of doing it from scratch.

The result is this portfolio of ten classic effects running in a single HTML file. It's all vanilla JavaScript writing to a <canvas> element, with no external libraries. It was a fun challenge to implement things like:

* The color palette cycling and smooth fading in the Plasma demo. * The buffer-averaging algorithm for the Fire effect to make the flames feel more natural. * The distance-based texture crossfading in the Tunnel to create the illusion of flying through different sections. * A 2D scalar field for the Metaballs to calculate the surface normals for that classic blended, metallic look (I did the best I could with the given constraints).

It was a great exercise in getting back to first principles and a reminder of how much those early demo programmers could accomplish with so little. I hope it brings back some good memories for others who grew up with this stuff.

I'd love to hear about your favorite classic demos or if there are any other iconic effects you think would be a fun challenge to add.

Cheers!