Matrix digital rain · grok-4.20
Create the Matrix digital rain effect on a full-screen black canvas: columns of falling green katakana glyphs with a trailing fade and a brighter leading character.
transcript · 6 messages
Create the Matrix digital rain effect on a full-screen black canvas: columns of falling green katakana glyphs with a trailing fade and a brighter leading character.
thinking
The task is to create the Matrix digital rain effect on a full-screen black canvas: columns of falling green katakana glyphs with a trailing fade and a brighter leading character. It must be a single-...The task is to create the Matrix digital rain effect in a single-page web app using one index.html file with CSS and JS inside.
I need to implement it using HTML5 Canvas.
Key points:
- Full-screen black canvas
- Columns of falling green katakana glyphs
- Trailing fade
- Brighter leading character
- Random katakana characters
- Different speeds per column
- Reset when reaching bottom
Katakana Unicode: U+30A0 to U+30FF, but commonly use a string like 'ｦｧｨｩｪｫｬｭｮ etc., but easier to use range.
For code: use String.fromCharCode for katakana.
Font: monospace with size 15px or so.
For brighter leading: in the loop, for each column, draw the body with #0F0, and the head (last one) with #0FF or brighter.
But since only one char per column drawn per frame, the current one is the head.
To make it brighter, use ctx.fillStyle = '#0F0' for most, but change for the one at the "head" position? But since it's falling, the current drawn is the leading one.
The implementation I thought is standard and works.
Let me write the code.
First, HTML:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Matrix Digital Rain</title>
<style>
body { margin: 0; background: black; overflow: hidden; }
canvas { display: block; }
</style>
</head>
<body>
<canvas id="c"></canvas>
<script>
// JS here
const canvas = document.getElementById('c');
const ctx = canvas.getContext('2d');
let width, height;
function resize() {
width = canvas.width = window .innerWidth;
height = canvas.height = window.innerHeight;
}
window.addEventListener('resize', resize);
resize();
const fontSize = 15;
const columns = Math.floor(width / fontSize);
let drops = new Array(columns);
for (let i = 0; i < columns; i++) {
drops[i] = Math.floor(Math.random() * height / fontSize);
}
const katakana = [];
for (let i = 0x30A0; i <= 0x30FF; i++) {
katakana.push(String.fromCharCode(i));
}
function draw() {
ctx.fillStyle = 'rgba(0,0,0,0.05)';
ctx.fillRect(0,0,width,height);
ctx.fillStyle = '#0F0';
ctx.font = fontSize + 'px monospace';
for (let i = 0; i < columns; i ++) {
const y = drops[i] * fontSize;
const char = katakana[Math.floor(Math.random() * katakana.length)];
ctx.index.html (6299 bytes)Successfully wrote 6299 bytes to index.html
thinking
The task is complete. The file index.html has been created with a full-screen Matrix digital rain effect using katakana glyphs. It features:
{"command":"ls -la"}total 8 drwxr-sr-x. 2 node node 24 Aug 1 20:17 . drwxrwsrwx. 3 root node 16 Aug 1 20:16 .. -rw-r--r--. 1 node node 6379 Aug 1 20:17 index.html
thinking
The file is written successfully. The Matrix digital rain effect is implemented in a single self-contained index.html file with canvas, CSS in style tag, and JS in script tag. No external resources ar...
The file `index.html` has been created with a full-screen Matrix digital rain effect (green katakana glyphs, trailing fade, brighter leading characters, organic variable speeds, interactivity, etc.). Open it in a browser to view/run.
TAKE IT TO CODE
A single self-contained HTML file — copy it and open in any browser, or reuse the prompt with your own pi-agent run.
RUN
EVALUATION
Classic Matrix digital rain with falling katakana glyphs, fade trails, and bright leading chars; animates continuously on its own.
Vision grade · anthropic/claude-sonnet-5
MEASUREMENTS
Raw readings from the capture, not a verdict — the grade above is the only judgement. Percentages are how much of the screen changed; the measure under-reports sparse motion on a dark background.