Matrix digital rain · deepseek-v3.2
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 · 36 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
I'll create a single-page web app with the Matrix digital rain effect. Let me first check the current directory and then write the index.html file.
{"command":"pwd && ls -la"}/workspace total 4 drwxrwxrwx 2 node node 64 Jul 22 17:15 . drwxr-xr-x 1 root root 4096 Jul 22 17:15 ..
thinking
Now I'll write the index.html file with the Matrix digital rain effect. The effect will have columns of falling green katakana characters, with a trailing fade and a brighter leading character. I'll use HTML5 canvas and JavaScript for the animation. Let's create a self-contained file.
index.html (9872 bytes)Successfully wrote 9872 bytes to index.html
thinking
Now let's verify the file was created and view it to ensure it works as expected. I'll also open a quick preview using a simple Python HTTP server to see if the canvas renders. Let's first check the file size and content.
{"command":"ls -lh index.html"}-rw-r--r-- 1 node node 9.7K Jul 22 17:16 index.html
thinking
Let's start a simple HTTP server in the background to serve the file and check if the page loads correctly. We'll also do a quick curl to ensure the HTML is valid.
{"command":"python3 -m http.server 8080 > /dev/null 2>&1 &"}(no output)
thinking
Now let's fetch the page with curl to see if it serves. Let's also kill the server after a moment.
{"command":"sleep充当2 && curl -s http://localhost:8080/ | head -5"}/bin/bash: line 1: $'sleep\345\205\205\345\275\2232': command not found Command exited with code 127
thinking
Oops, I typed Chinese characters accidentally. Let me kill the server and restart with a cleaner approach. Let's first kill the python server and then just verify the HTML content directly.
{"command":"pkill -f \"http.server 8080\" 2>/dev/null || true"}(no output)
thinking
Now let's examine the HTML content to ensure it includes all necessary parts. Let's read the first few lines and the script section.
{"path":"index.html","limit":30}<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Matrix Digital Rain</title> <style> * { margin: 0; padding: 0; box-sizing: border-box; } html, body { height: 100%; overflow: hidden; background: #000; } canvas { display: block; width: 100%; height: 100%; } .controls { position: fixed; bottom: 20px; left: 20px; color: #0f0; [264 more lines in file. Use offset=31 to continue.]
thinking
Let's also check the script section to ensure the katakana range is correct and the animation loop works. Let's read a portion of the script.
{"path":"index.html","offset":200,"limit":100}// Leading character is brightest opacity = 1; } else { // Exponential fade for trailing characters opacity = Math.pow(0.7, i); } // Adjust brightness based on control const brightnessFactor = brightness / 5; const r = 0; const g = Math.min(255, Math.floor(255 * opacity * brightnessFactor)); const b = 0; ctx.fillStyle = `rgb(${r}, ${g}, ${b})`; // Draw character ctx.fillText( col.chars[i], col.x, col.y - i * fontSize ); } col.updateCount++; } // Update column position function updateColumn(col) { col.y += col.speed * (speed / 15); // Reset column when it goes off screen if (col.y - col.length * (columnWidth * 0.8) > canvas.height) { col.y = Math.random() * -canvas.height; col.length = Math.floor(Math.random() * 15) + 5; col.speed = Math.random() * 5 + 5; col.chars = []; col.updateCount = 0; } } // Animation loop function animate() { // Clear with slight fade effect for trailing glow ctx.fillStyle = 'rgba(0, 0, 0, 0.1)'; ctx.fillRect(0, 0, canvas.width, canvas.height); // Update and draw each column columns.forEach(col => { updateColumn(col); drawColumn(col); }); requestAnimationFrame(animate); } // Start animation animate(); // Add some interactivity: mouse affects columns let mouseX = 0, mouseY = 0; document.addEventListener('mousemove', function(e) { mouseX = e.clientX; mouseY = e.clientY; // Affect columns near mouse columns.forEach(col => { const distance = Math.abs(col.x - mouseX); if (distance < 100) { // Speed up columns near mouse const influence = 1 - (distance / 100); col.speed += influence * 3; } }); }); // Touch support document.addEventListener('touchmove', function(e) { if (e.touches.length > 0) { mouseX = e.touches[0].clientX; mouseY = e.touches[0].clientY; columns.forEach(col => { const distance = Math.abs(col.x - mouseX); if (distance < 100) { const influence = 1 - (distance / 100); col.speed += influence * 3; } }); } e.preventDefault(); }, { passive: false }); })(); </script> </body> </html>
thinking
The script looks good. However, I noticed a bug: `columnWidth` is declared with `const` initially, but later in the density control event listener we try to reassign it (`columnWidth = Math.max(10, canvas.width / density);`). That will cause an error because `columnWidth` is a constant. I need to change that to `let`. Also, we need to recalculate columns when density changes. Let's fix that. Also, the `columnWidth` variable should be declared with `let` at the top of the script, and the `initMatrix` function should use that variable. Let's edit the file. First, let's see the exact lines around the variable declaration. Let's read from line 70 to 100.
{"path":"index.html","offset":70,"limit":40}font-size: 1.2em; margin-bottom: 5px; } .title p { font-size: 0.9em; opacity: 0.8; } @media (max-width: 768px) { .controls, .title { font-size: 12px; padding: 8px; } .title h1 { font-size: 1em; } } </style> </head> <body> <div class="title"> <h1>Matrix Digital Rain</h1> <p>Green katakana glyphs falling with trailing fade</p> </div> <canvas id="matrixCanvas"></canvas> <div class="controls"> <label for="speed">Speed:</label> <input type="range" id="speed" min="1" max="30" value="15"> <span id="speedValue">15</span> <br> <label for="density">Density:</label> <input type="range" id="density" min="5" max="50" value="20"> <span id="densityValue">20</span> <br> <label for="brightness">Brightness:</label> <input type="range" id="brightness" min="1" max="10" value="5"> <span id="brightnessValue">5</span> </div> [185 more lines in file. Use offset=110 to continue.]
thinking
Now find the script section where `columnWidth` is defined. Let's search for "columnWidth" in the file using bash.
{"command":"grep -n \"columnWidth\" index.html"}140: const columnWidth = 20; // pixels between columns 150: const columnCount = Math.floor(canvas.width / columnWidth); 154: x: i * columnWidth, 172: columnWidth = Math.max(10, canvas.width / density); 184: const fontSize = Math.floor(columnWidth * 0.8); 231: if (col.y - col.length * (columnWidth * 0.8) > canvas.height) {
thinking
So line 140 declares `const columnWidth`. Need to change that to `let`. Also line 172 tries to reassign, which we'll keep. Also, we need to update the `initMatrix` function to use the current `columnWidth` variable (it already does). Let's edit the file to change the declaration and ensure the density slider works properly. We'll also need to ensure the `columnWidth` variable is accessible within the density event handler (it's in the same scope). Let's make the edit. First, we need to locate the exact lines around line 140. Let's read lines 135-180 to see the context.
{"path":"index.html","offset":135,"limit":50}katakana.push(String.fromCharCode(i)); } // Matrix columns let columns = []; const columnWidth = 20; // pixels between columns // Parameters let speed = 15; // pixels per frame let density = 20; // columns per screen width let brightness = 5; // leading character brightness multiplier // Initialize matrix columns function initMatrix() { columns = []; const columnCount = Math.floor(canvas.width / columnWidth); for (let i = 0; i < columnCount; i++) { columns.push({ x: i * columnWidth, y: Math.random() * -canvas.height, // start above canvas length: Math.floor(Math.random() * 15) + 5, speed: Math.random() * 5 + 5, chars: [], updateCount: 0 }); } } // Update controls document.getElementById('speed').addEventListener('input', function(e) { speed = parseInt(e.target.value); document.getElementById('speedValue').textContent = speed; }); document.getElementById('density').addEventListener('input', function(e) { density = parseInt(e.target.value); columnWidth = Math.max(10, canvas.width / density); initMatrix(); document.getElementById('densityValue').textContent = density; }); document.getElementById('brightness').addEventListener('input', function(e) { brightness = parseInt(e.target.value); document.getElementById('brightnessValue').textContent = brightness; }); // Draw a column function drawColumn(col) { const fontSize = Math.floor(columnWidth * 0.8); [110 more lines in file. Use offset=185 to continue.]
thinking
Now we need to change line 140 from `const columnWidth = 20;` to `let columnWidth = 20;`. Also we should adjust the columnWidth calculation to use density, but the current formula `Math.max(10, canvas.width / density)` will give a columnWidth in pixels, but we also have the columnWidth used for spacing. That's fine. However, note that the columnWidth is also used for fontSize calculation (columnWidth * 0.8). That's okay. But there's a potential issue: when density changes, we recalc columnWidth and call initMatrix, which uses the updated columnWidth. However, the existing columns array is replaced. That's fine. But we also need to ensure that the columnWidth variable is accessible inside the drawColumn and updateColumn functions (they are nested inside the same closure, so they have access). That's fine. Now we also need to adjust the columnWidth initial value to be based on density? Currently it's 20. Maybe we should compute initial columnWidth based on initial density (20). Let's set columnWidth = Math.max(10, canvas.width / density); after canvas is resized. But we need to call that after canvas dimensions are set. Let's modify the initMatrix to compute columnWidth based on density, and also update the columnWidth variable accordingly. Actually, we can keep columnWidth as a variable that is updated when density changes, and also when canvas resizes? The density slider changes columnWidth, but if the window is resized, columnWidth should be recalculated based on the same density? Actually, density is defined as "columns per screen width". So when the window resizes, we want to keep the same density (columns per screen width) and adjust columnWidth accordingly. However, the density slider is independent of window size. Let's make columnWidth always equal canvas.width / density (with a min of 10). That will keep density consistent across resizes. Thus we need to update columnWidth both on density change and on window resize. Let's modify the resizeCanvas function to recompute columnWidth based on current density and call initMatrix. Also we need to keep the density variable accessible. Let's make the following changes: 1. Change `const columnWidth` to `let columnWidth`. 2. Create a function `updateColumnWidth()` that sets columnWidth = Math.max(10, canvas.width / density). 3. Call that function in resizeCanvas and in the density event listener, then call initMatrix. Let's edit the file. We'll need to replace multiple sections. We'll do it in one edit call with multiple edits. Let's first write out the exact old text and new text. We'll locate the line numbers precisely. Let's get the full script section from line 135 to maybe 250 to have enough context. Let's read more lines.
{"path":"index.html","offset":135,"limit":120}katakana.push(String.fromCharCode(i)); } // Matrix columns let columns = []; const columnWidth = 20; // pixels between columns // Parameters let speed = 15; // pixels per frame let density = 20; // columns per screen width let brightness = 5; // leading character brightness multiplier // Initialize matrix columns function initMatrix() { columns = []; const columnCount = Math.floor(canvas.width / columnWidth); for (let i = 0; i < columnCount; i++) { columns.push({ x: i * columnWidth, y: Math.random() * -canvas.height, // start above canvas length: Math.floor(Math.random() * 15) + 5, speed: Math.random() * 5 + 5, chars: [], updateCount: 0 }); } } // Update controls document.getElementById('speed').addEventListener('input', function(e) { speed = parseInt(e.target.value); document.getElementById('speedValue').textContent = speed; }); document.getElementById('density').addEventListener('input', function(e) { density = parseInt(e.target.value); columnWidth = Math.max(10, canvas.width / density); initMatrix(); document.getElementById('densityValue').textContent = density; }); document.getElementById('brightness').addEventListener('input', function(e) { brightness = parseInt(e.target.value); document.getElementById('brightnessValue').textContent = brightness; }); // Draw a column function drawColumn(col) { const fontSize = Math.floor(columnWidth * 0.8); ctx.font = `bold ${fontSize}px monospace`; // Generate characters for this column if needed if (col.chars.length === 0 || col.updateCount % 5 === 0) { col.chars = []; for (let i = 0; i < col.length; i++) { col.chars.push(katakana[Math.floor(Math.random() * katakana.length)]); } } // Draw characters with gradient effect for (let i = 0; i < col.chars.length; i++) { // Calculate opacity: head is brightest, tail fades let opacity; if (i === 0) { // Leading character is brightest opacity = 1; } else { // Exponential fade for trailing characters opacity = Math.pow(0.7, i); } // Adjust brightness based on control const brightnessFactor = brightness / 5; const r = 0; const g = Math.min(255, Math.floor(255 * opacity * brightnessFactor)); const b = 0; ctx.fillStyle = `rgb(${r}, ${g}, ${b})`; // Draw character ctx.fillText( col.chars[i], col.x, col.y - i * fontSize ); } col.updateCount++; } // Update column position function updateColumn(col) { col.y += col.speed * (speed / 15); // Reset column when it goes off screen if (col.y - col.length * (columnWidth * 0.8) > canvas.height) { col.y = Math.random() * -canvas.height; col.length = Math.floor(Math.random() * 15) + 5; col.speed = Math.random() * 5 + 5; col.chars = []; col.updateCount = 0; } } // Animation loop function animate() { // Clear with slight fade effect for trailing glow ctx.fillStyle = 'rgba(0, 0, 0, 0.1)'; ctx.fillRect(0, 0, canvas.width, canvas.height); // Update and draw each column columns.forEach(col => { updateColumn(col); drawColumn(col); }); requestAnimationFrame(animate); } [40 more lines in file. Use offset=255 to continue.]
thinking
Now we need to also see the resizeCanvas function. Let's find it earlier in the script. Let's search for "resizeCanvas". Let's get lines 60-140
{"path":"index.html"}<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Matrix Digital Rain</title> <style> * { margin: 0; padding: 0; box-sizing: border-box; } html, body { height: 100%; overflow: hidden; background: #000; } canvas { display: block; width: 100%; height: 100%; } .controls { position: fixed; bottom: 20px; left: 20px; color: #0f0; font-family: monospace; font-size: 14px; z-index: 100; background: rgba(0, 0, 0, 0.7); padding: 10px; border-radius: 5px; border: 1px solid #0f0; } .controls label { display: inline-block; margin-right: 10px; } .controls input[type="range"] { vertical-align: middle; margin: 0 5px; } .controls span { display: inline-block; min-width: 30px; } .title { position: fixed; top: 20px; left: 20px; color: #0f0; font-family: monospace; font-size: 18px; z-index: 100; background: rgba(0, 0, 0, 0.7); padding: 10px; border-radius: 5px; border: 1px solid #0f0; } .title h1 { font-size: 1.2em; margin-bottom: 5px; } .title p { font-size: 0.9em; opacity: 0.8; } @media (max-width: 768px) { .controls, .title { font-size: 12px; padding: 8px; } .title h1 { font-size: 1em; } } </style> </head> <body> <div class="title"> <h1>Matrix Digital Rain</h1> <p>Green katakana glyphs falling with trailing fade</p> </div> <canvas id="matrixCanvas"></canvas> <div class="controls"> <label for="speed">Speed:</label> <input type="range" id="speed" min="1" max="30" value="15"> <span id="speedValue">15</span> <br> <label for="density">Density:</label> <input type="range" id="density" min="5" max="50" value="20"> <span id="densityValue">20</span> <br> <label for="brightness">Brightness:</label> <input type="range" id="brightness" min="1" max="10" value="5"> <span id="brightnessValue">5</span> </div> <script> (function() { 'use strict'; // Canvas setup const canvas = document.getElementById('matrixCanvas'); const ctx = canvas.getContext('2d'); // Set canvas dimensions to full window function resizeCanvas() { canvas.width = window.innerWidth; canvas.height = window.innerHeight; initMatrix(); } window.addEventListener('resize', resizeCanvas); resizeCanvas(); // Katakana characters (Unicode range: 30A0–30FF) const katakana = []; for (let i = 0x30A0; i <= 0x30FF; i++) { katakana.push(String.fromCharCode(i)); } // Add some half-width katakana (FF65–FF9F) for variety for (let i = 0xFF65; i <= 0xFF9F; i++) { katakana.push(String.fromCharCode(i)); } // Matrix columns let columns = []; const columnWidth = 20; // pixels between columns // Parameters let speed = 15; // pixels per frame let density = 20; // columns per screen width let brightness = 5; // leading character brightness multiplier // Initialize matrix columns function initMatrix() { columns = []; const columnCount = Math.floor(canvas.width / columnWidth); for (let i = 0; i < columnCount; i++) { columns.push({ x: i * columnWidth, y: Math.random() * -canvas.height, // start above canvas length: Math.floor(Math.random() * 15) + 5, speed: Math.random() * 5 + 5, chars: [], updateCount: 0 }); } } // Update controls document.getElementById('speed').addEventListener('input', function(e) { speed = parseInt(e.target.value); document.getElementById('speedValue').textContent = speed; }); document.getElementById('density').addEventListener('input', function(e) { density = parseInt(e.target.value); columnWidth = Math.max(10, canvas.width / density); initMatrix(); document.getElementById('densityValue').textContent = density; }); document.getElementById('brightness').addEventListener('input', function(e) { brightness = parseInt(e.target.value); document.getElementById('brightnessValue').textContent = brightness; }); // Draw a column function drawColumn(col) { const fontSize = Math.floor(columnWidth * 0.8); ctx.font = `bold ${fontSize}px monospace`; // Generate characters for this column if needed if (col.chars.length === 0 || col.updateCount % 5 === 0) { col.chars = []; for (let i = 0; i < col.length; i++) { col.chars.push(katakana[Math.floor(Math.random() * katakana.length)]); } } // Draw characters with gradient effect for (let i = 0; i < col.chars.length; i++) { // Calculate opacity: head is brightest, tail fades let opacity; if (i === 0) { // Leading character is brightest opacity = 1; } else { // Exponential fade for trailing characters opacity = Math.pow(0.7, i); } // Adjust brightness based on control const brightnessFactor = brightness / 5; const r = 0; const g = Math.min(255, Math.floor(255 * opacity * brightnessFactor)); const b = 0; ctx.fillStyle = `rgb(${r}, ${g}, ${b})`; // Draw character ctx.fillText( col.chars[i], col.x, col.y - i * fontSize ); } col.updateCount++; } // Update column position function updateColumn(col) { col.y += col.speed * (speed / 15); // Reset column when it goes off screen if (col.y - col.length * (columnWidth * 0.8) > canvas.height) { col.y = Math.random() * -canvas.height; col.length = Math.floor(Math.random() * 15) + 5; col.speed = Math.random() * 5 + 5; col.chars = []; col.updateCount = 0; } } // Animation loop function animate() { // Clear with slight fade effect for trailing glow ctx.fillStyle = 'rgba(0, 0, 0, 0.1)'; ctx.fillRect(0, 0, canvas.width, canvas.height); // Update and draw each column columns.forEach(col => { updateColumn(col); drawColumn(col); }); requestAnimationFrame(animate); } // Start animation animate(); // Add some interactivity: mouse affects columns let mouseX = 0, mouseY = 0; document.addEventListener('mousemove', function(e) { mouseX = e.clientX; mouseY = e.clientY; // Affect columns near mouse columns.forEach(col => { const distance = Math.abs(col.x - mouseX); if (distance < 100) { // Speed up columns near mouse const influence = 1 - (distance / 100); col.speed += influence * 3; } }); }); // Touch support document.addEventListener('touchmove', function(e) { if (e.touches.length > 0) { mouseX = e.touches[0].clientX; mouseY = e.touches[0].clientY; columns.forEach(col => { const distance = Math.abs(col.x - mouseX); if (distance < 100) { const influence = 1 - (distance / 100); col.speed += influence * 3; } }); } e.preventDefault(); }, { passive: false }); })(); </script> </body> </html>
thinking
Great, now we have the full file. Let's make the edits.
First, change `const columnWidth = 20;` to `let columnWidth = 20;`.
Second, create a function `updateColumnWidth()` and call it in resizeCanvas and density listener. But we also need to compute columnWidth based on density initially. Let's add a function `updateColumnWidth()` that sets columnWidth = Math.max(10, canvas.width / density). Then call it after canvas resize, and also call initMatrix after updating columnWidth. However, note that initMatrix already uses columnWidth. So we need to call updateColumnWidth before initMatrix.
We need to modify the resizeCanvas function to updateColumnWidth then initMatrix. Also, we need to call updateColumnWidth on initial load after canvas dimensions are set. We'll adjust the flow.
Let's write the edit with multiple changes:
1. Replace line "const columnWidth = 20;" with "let columnWidth = 20;"
2. Replace the resizeCanvas function block with a new version that updates columnWidth:
Old text:
```
// Set canvas dimensions to full window
function resizeCanvas() {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
initMatrix();
}
```
New text:
```
// Set canvas dimensions to full window
function resizeCanvas() {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
updateColumnWidth();
initMatrix();
}
// Update column width based on density and canvas size
function updateColumnWidth() {
columnWidth = Math.max(10, canvas.width / density);
}
```
3. Replace the density event listener block to call updateColumnWidth instead of directly assigning columnWidth:
Old text:
```
document.getElementById('density').addEventListener('input', function(e) {
density = parseInt(e.target.value);
columnWidth = Math.max(10, canvas.width / density);
initMatrix();
document.getElementById('densityValue').textContent = density;
});
```
New text:
```
document.getElementById('density').addEventListener('input', function(e) {
density = parseInt(e.target.value);
updateColumnWidth();
initMatrix();
document.getElementById('densityValue').textContent = density;
});
```
Note: we also need to call updateColumnWidth() initially after canvas resize but before initMatrix? Actually, we already call resizeCanvas() at the bottom, which now includes updateColumnWidth. That's fine.
But also need to ensure that columnWidth is initialized with the correct value before the first initMatrix call. Since we call resizeCanvas() after defining everything, and resizeCanvas calls updateColumnWidth, it will set columnWidth based on canvas.width (which is set) and density (initial 20). That's good.
Now we also need to adjust the initMatrix function to use columnWidth variable (it already does). However, note that initMatrix uses columnWidth which is now updated after resizeCanvas calls updateColumnWidth. Since updateColumnWidth is called before initMatrix in resizeCanvas, we're fine.
Now we also need to update the columnWidth variable when density changes but canvas width hasn't changed; we already do that.
Now we must ensure that columnWidth is accessible in drawColumn and updateColumn (they are closures and have access). Yes.
Let's apply these edits. We'll do them in one edit call. Let's craft the exact old strings and new strings.
First, find the exact text for each block. We'll need to be careful with whitespace. Let's copy the exact lines.
I'll write the edit command now. Let's open a new editor. We'll need to ensure we don't have overlapping edits. We'll do three separate edits but combine them into one edit call with three entries.
Let's write the edit:{"path":"index.html","edits":[{"oldText":" const columnWidth = 20; // pixels between columns","newText":" let columnWiSuccessfully replaced 3 block(s) in index.html.
thinking
Great! Now we should also ensure that the columnWidth used in the updateColumn check for offscreen uses the same columnWidth variable. That's already using columnWidth (line 231). That's fine. Now there's a small issue: the columnWidth variable is used in drawColumn for fontSize, but columnWidth may now be fractional (e.g., canvas.width / density). That's okay; fontSize will be floor of 0.8 * columnWidth, which may be less than 10px if columnWidth is small. That's fine. Now we should also consider adding a min font size to ensure characters are visible. But we already have a min columnWidth of 10 pixels, so fontSize min is floor(8) = 8px. That's okay. Now we should test the page. Let's start a simple HTTP server and fetch the page to verify no JavaScript errors. We'll also check if the canvas renders. Let's do a quick curl and see if the HTML is valid. Let's also kill any existing python servers. First, kill them.
{"command":"pkill -f \"http.server\" 2>/dev/null || true"}(no output)
thinking
Now start a server in the background and run a quick curl to get the page and see if there are any obvious errors. Let's also output the first few lines of the script to ensure our changes are there. Let's first check the edited parts
{"path":"index.html"}<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Matrix Digital Rain</title> <style> * { margin: 0; padding: 0; box-sizing: border-box; } html, body { height: 100%; overflow: hidden; background: #000; } canvas { display: block; width: 100%; height: 100%; } .controls { position: fixed; bottom: 20px; left: 20px; color: #0f0; font-family: monospace; font-size: 14px; z-index: 100; background: rgba(0, 0, 0, 0.7); padding: 10px; border-radius: 5px; border: 1px solid #0f0; } .controls label { display: inline-block; margin-right: 10px; } .controls input[type="range"] { vertical-align: middle; margin: 0 5px; } .controls span { display: inline-block; min-width: 30px; } .title { position: fixed; top: 20px; left: 20px; color: #0f0; font-family: monospace; font-size: 18px; z-index: 100; background: rgba(0, 0, 0, 0.7); padding: 10px; border-radius: 5px; border: 1px solid #0f0; } .title h1 { font-size: 1.2em; margin-bottom: 5px; } .title p { font-size: 0.9em; opacity: 0.8; } @media (max-width: 768px) { .controls, .title { font-size: 12px; padding: 8px; } .title h1 { font-size: 1em; } } </style> </head> <body> <div class="title"> <h1>Matrix Digital Rain</h1> <p>Green katakana glyphs falling with trailing fade</p> </div> <canvas id="matrixCanvas"></canvas> <div class="controls"> <label for="speed">Speed:</label> <input type="range" id="speed" min="1" max="30" value="15"> <span id="speedValue">15</span> <br> <label for="density">Density:</label> <input type="range" id="density" min="5" max="50" value="20"> <span id="densityValue">20</span> <br> <label for="brightness">Brightness:</label> <input type="range" id="brightness" min="1" max="10" value="5"> <span id="brightnessValue">5</span> </div> <script> (function() { 'use strict'; // Canvas setup const canvas = document.getElementById('matrixCanvas'); const ctx = canvas.getContext('2d'); // Set canvas dimensions to full window function resizeCanvas() { canvas.width = window.innerWidth; canvas.height = window.innerHeight; updateColumnWidth(); initMatrix(); } // Update column width based on density and canvas size function updateColumnWidth() { columnWidth = Math.max(10, canvas.width / density); } window.addEventListener('resize', resizeCanvas); resizeCanvas(); // Katakana characters (Unicode range: 30A0–30FF) const katakana = []; for (let i = 0x30A0; i <= 0x30FF; i++) { katakana.push(String.fromCharCode(i)); } // Add some half-width katakana (FF65–FF9F) for variety for (let i = 0xFF65; i <= 0xFF9F; i++) { katakana.push(String.fromCharCode(i)); } // Matrix columns let columns = []; let columnWidth = 20; // pixels between columns // Parameters let speed = 15; // pixels per frame let density = 20; // columns per screen width let brightness = 5; // leading character brightness multiplier // Initialize matrix columns function initMatrix() { columns = []; const columnCount = Math.floor(canvas.width / columnWidth); for (let i = 0; i < columnCount; i++) { columns.push({ x: i * columnWidth, y: Math.random() * -canvas.height, // start above canvas length: Math.floor(Math.random() * 15) + 5, speed: Math.random() * 5 + 5, chars: [], updateCount: 0 }); } } // Update controls document.getElementById('speed').addEventListener('input', function(e) { speed = parseInt(e.target.value); document.getElementById('speedValue').textContent = speed; }); document.getElementById('density').addEventListener('input', function(e) { density = parseInt(e.target.value); updateColumnWidth(); initMatrix(); document.getElementById('densityValue').textContent = density; }); document.getElementById('brightness').addEventListener('input', function(e) { brightness = parseInt(e.target.value); document.getElementById('brightnessValue').textContent = brightness; }); // Draw a column function drawColumn(col) { const fontSize = Math.floor(columnWidth * 0.8); ctx.font = `bold ${fontSize}px monospace`; // Generate characters for this column if needed if (col.chars.length === 0 || col.updateCount % 5 === 0) { col.chars = []; for (let i = 0; i < col.length; i++) { col.chars.push(katakana[Math.floor(Math.random() * katakana.length)]); } } // Draw characters with gradient effect for (let i = 0; i < col.chars.length; i++) { // Calculate opacity: head is brightest, tail fades let opacity; if (i === 0) { // Leading character is brightest opacity = 1; } else { // Exponential fade for trailing characters opacity = Math.pow(0.7, i); } // Adjust brightness based on control const brightnessFactor = brightness / 5; const r = 0; const g = Math.min(255, Math.floor(255 * opacity * brightnessFactor)); const b = 0; ctx.fillStyle = `rgb(${r}, ${g}, ${b})`; // Draw character ctx.fillText( col.chars[i], col.x, col.y - i * fontSize ); } col.updateCount++; } // Update column position function updateColumn(col) { col.y += col.speed * (speed / 15); // Reset column when it goes off screen if (col.y - col.length * (columnWidth * 0.8) > canvas.height) { col.y = Math.random() * -canvas.height; col.length = Math.floor(Math.random() * 15) + 5; col.speed = Math.random() * 5 + 5; col.chars = []; col.updateCount = 0; } } // Animation loop function animate() { // Clear with slight fade effect for trailing glow ctx.fillStyle = 'rgba(0, 0, 0, 0.1)'; ctx.fillRect(0, 0, canvas.width, canvas.height); // Update and draw each column columns.forEach(col => { updateColumn(col); drawColumn(col); }); requestAnimationFrame(animate); } // Start animation animate(); // Add some interactivity: mouse affects columns let mouseX = 0, mouseY = 0; document.addEventListener('mousemove', function(e) { mouseX = e.clientX; mouseY = e.clientY; // Affect columns near mouse columns.forEach(col => { const distance = Math.abs(col.x - mouseX); if (distance < 100) { // Speed up columns near mouse const influence = 1 - (distance / 100); col.speed += influence * 3; } }); }); // Touch support document.addEventListener('touchmove', function(e) { if (e.touches.length > 0) { mouseX = e.touches[0].clientX; mouseY = e.touches[0].clientY; columns.forEach(col => { const distance = Math.abs(col.x - mouseX); if (distance < 100) { const influence = 1 - (distance / 100); col.speed += influence * 3; } }); } e.preventDefault(); }, { passive: false }); })(); </script> </body> </html>
thinking
All changes look good. However, there's a scoping issue: The `updateColumnWidth` function is defined before `columnWidth`, `density`, and `canvas` are defined? Actually, `updateColumnWidth` is defined after `resizeCanvas` but before `columnWidth` and `density` variables. In JavaScript, function declarations are hoisted, but they still refer to variables in their lexical scope. However, `columnWidth` and `density` are not yet declared when `updateColumnWidth` is defined (they are declared later). That's fine because `updateColumnWidth` references `columnWidth` and `density` which are in the closure; they will be available when the function is called, as long as they are declared somewhere in the outer scope. They are declared later, but still in the same closure (the outer IIFE). That's okay because JavaScript closures capture variables, not values at definition time. When `updateColumnWidth` is invoked, `columnWidth` and `density` will have been initialized (since we call `updateColumnWidth` after the variable declarations? Wait, we call `resizeCanvas` after the variable declarations? Let's examine: The code order is:
1. canvas, ctx
2. resizeCanvas function (includes updateColumnWidth call)
3. updateColumnWidth function (references columnWidth and density)
4. window.addEventListener('resize', resizeCanvas);
5. resizeCanvas(); // called after all variable declarations? Actually after this line, we have katakana arrays, then columnWidth, density etc. But the call to resizeCanvas() is before columnWidth and density are declared! That's a problem.
We need to move the variable declarations before the call to resizeCanvas(). However, note that `columnWidth` and `density` are used in `updateColumnWidth`. So we need to declare them before updateColumnWidth is called. Let's reorder: declare columnWidth, density, brightness after katakana arrays but before the function definitions? Actually we need columnWidth and density for updateColumnWidth. Let's move the variable declarations before the function definitions, but after katakana arrays. However, note that `updateColumnWidth` also uses `canvas.width`, which is set only after resizeCanvas is called. That's okay because updateColumnWidth is called inside resizeCanvas after canvas dimensions are set.
But we need to ensure that columnWidth and density exist before we define updateColumnWidth (they will be defined later). That's fine because function declaration hoisting doesn't require variables to exist yet. However, we must ensure that when updateColumnWidth is called, those variables are defined. Since we call resizeCanvas after the variable declarations, we should move the variable declarations before the first resizeCanvas call.
Let's restructure: after katakana arrays, declare columns, columnWidth, speed, density, brightness. Then define functions (initMatrix, updateColumnWidth, etc.), then call resizeCanvas. That way all variables are initialized before any function that uses them is called.
Let's edit the file again. We'll need to move a block of code. We'll do this by replacing the section from after katakana arrays up to the call to resizeCanvas. Let's find the exact lines.
We'll replace from line "// Matrix columns" (around line 140) up to line "resizeCanvas();" (around line 160) with restructured code.
Let's first copy the exact text we want to replace. We'll view lines 135-180 again. Let's compute line numbers after earlier edits; but we can just replace based on unique strings.
We'll replace:
```
// Matrix columns
let columns = [];
let columnWidth = 20; // pixels between columns
// Parameters
let speed = 15; // pixels per frame
let density = 20; // columns per screen width
let brightness = 5; // leading character brightness multiplier
// Initialize matrix columns
function initMatrix() {
columns = [];
const columnCount = Math.floor(canvas.width / columnWidth);
for (let i = 0; i < columnCount; i++) {
columns.push({
x: i * columnWidth,
y: Math.random() * -canvas.height, // start above canvas
length: Math.floor(Math.random() * 15) + 5,
speed: Math.random() * 5 + 5,
chars: [],
updateCount: 0
});
}
}
// Update controls
document.getElementById('speed').addEventListener('input', function(e) {
speed = parseInt(e.target.value);
document.getElementById('speedValue').textContent = speed;
});
document.getElementById('density').addEventListener('input', function(e) {
density = parseInt(e.target.value);
updateColumnWidth();
initMatrix();
document.getElementById('densityValue').textContent = density;
});
document.getElementById('brightness').addEventListener('input', function(e) {
brightness = parseInt(e.target.value);
document.getElementById('brightnessValue').textContent = brightness;
});
```
But we also need to keep the function definitions for drawColumn, updateColumn, animate, etc. Those are after the event listeners. Actually the event listeners are after the function definitions? Let's look at the current order:
1. canvas, ctx
2. resizeCanvas function (calls updateColumnWidth and initMatrix)
3. updateColumnWidth function
4. window.addEventListener('resize', resizeCanvas);
5. resizeCanvas(); // called before columnWidth is declared! This is the problem.
We need to move the variable declarations before the first resizeCanvas call. Let's restructure as follows:
- Keep canvas, ctx.
- Define katakana arrays.
- Declare columns, columnWidth, speed, density, brightness.
- Define initMatrix, updateColumnWidth, drawColumn, updateColumn, animate.
- Define event listeners for controls.
- Call resizeCanvas (which will use the declared variables).
- Then add window event listener and start animation.
But note that we already have a call to resizeCanvas right after window.addEventListener. We'll keep that order but move variable declarations earlier.
Let's write the new code block from after katakana arrays up to the line before "// Draw a column". We'll replace a larger chunk.
Let's first identify the exact boundaries. We'll replace from the line "// Matrix columns" to the line "// Draw a column". Let's find the exact text.
I'll search for "// Draw a column" in the file to see line number. Let's do a quick bash.{"command":"grep -n \"// Draw a column\" index.html"}188: // Draw a column
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
Only UI controls and title text render; canvas is blank black due to a JS init error, no rain effect visible.
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.
- Cannot access 'density' before initialization