Matrix digital rain · glm-5.3-flash
Output generated Cost / run $0.0018 Runtime 89.8s
Prompt for this run
Build an animated Matrix-style digital rain effect on a full-screen black canvas. Use HTML, CSS, and JavaScript as needed. Write it to `index.html` in the current working directory using your file tools. Inline your own CSS and JavaScript. Do not use external assets, CDNs, or network requests. No third-party libraries are provided. Required behavior: - Draw multiple independently moving columns of green katakana glyphs, each with a brighter leading character and a fading trail. - Vary column speed and start position. Recycle columns after they leave the bottom so the effect continues without accumulating off-screen state. - Provide Pause/Resume and Restart. Pause freezes the animation; Restart resets the columns and clears previous trails. - Resize the canvas and column layout to fit the viewport without stretching an old screenshot or leaving an uncovered strip. - Use locally available fonts and procedural drawing; no external fonts or images. Choose glyphs, brightness, and timing freely. Verify: Sample the animation at several moments to inspect independently moving columns, brighter leading glyphs, and fading trails. Pause and resume to check that the image freezes and continues, then use Restart and check that old trails are cleared.
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
METRICS
Transcript · 17 messages
Build an animated Matrix-style digital rain effect on a full-screen black canvas. Use HTML, CSS, and JavaScript as needed. Write it to `index.html` in the current working directory using your file tools. Inline your own CSS and JavaScript. Do not use external assets, CDNs, or network requests. No third-party libraries are provided. Required behavior: - Draw multiple independently moving columns of green katakana glyphs, each with a brighter leading character and a fading trail. - Vary column speed and start position. Recycle columns after they leave the bottom so the effect continues without accumulating off-screen state. - Provide Pause/Resume and Restart. Pause freezes the animation; Restart resets the columns and clears previous trails. - Resize the canvas and column layout to fit the viewport without stretching an old screenshot or leaving an uncovered strip. - Use locally available fonts and procedural drawing; no external fonts or images. Choose glyphs, brightness, and timing freely. Verify: Sample the animation at several moments to inspect independently moving columns, brighter leading glyphs, and fading trails. Pause and resume to check that the image freezes and continues, then use Restart and check that old trails are cleared.
index.html (3496 bytes)Successfully wrote to index.html
thinking
Wait — pause issue: I put `if (paused) { rafId = requestAnimationFrame(frame); return; }` — that keeps looping but not drawing, fine (freezes image). But dim fill each frame causes trails to fade — that's okay, trail glyph redraw each frame plus dim gives fading. Actually since I redraw trail glyphs each frame at same positions, and dim fades them, equilibrium: trails visible. Head redrawn bright each frame. OK.
One issue: textBaseline default alphabetic, fine.
Test in browser with motion sampling.{"action":"reload"}Frame 1, +0ms
[Browser image supplied to model]
{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart","images":"attached"}
{"action":"motion","delta":1500}Frame 1, +0ms
[Browser image supplied to model]
Frame 2, +632ms
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Frame 3, +1207ms
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Frame 4, +1812ms
[Browser image supplied to model]
{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart","images":"attached"}
thinking
Looks good: columns move independently, bright heads, fading trails. Test pause freeze and restart.
The rain looks good — independent columns, bright heads, fading trails. Now testing Pause/Resume and Restart.
{"action":"click","x":1102,"y":25}Frame 1, +0ms
[Browser image supplied to model]
{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart","images":"attached"}
{"action":"motion","delta":800}Frame 1, +0ms
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Frame 2, +557ms
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Frame 3, +1106ms
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Frame 4, +1661ms
[Browser image supplied to model]
{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Resume\nRestart","images":"attached"}
thinking
Frames identical — frozen. Now resume and restart, then restart check clearing.
Pause freezes correctly — all 4 frames identical. Now resume, then test Restart clearing.
{"action":"click","x":1102,"y":25}Frame 1, +0ms
[Browser image supplied to model]
{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart","images":"attached"}
thinking
Resumed (glyphs advanced slightly). Now click Restart and verify reset + clear.
{"action":"click","x":1156,"y":25}Frame 1, +0ms
[Browser image supplied to model]
{"console":["warning: An iframe which has both allow-scripts and allow-same-origin for its sandbox attribute can escape its sandboxing."],"dom":"Pause\nRestart","images":"attached"}
thinking
Restart cleared everything — old trails gone, columns reset above screen. Growth resumes; motion already verified. Done. Resize logic re-runs setup, clears canvas fully — no stretching/strip. Verified enough.
Restart works — canvas is fully cleared (old trails gone) and columns reset above the viewport, regrowing from the top. Done. `index.html` contains a self-contained Matrix digital rain app: - **Columns**: each column has independent speed, random start offset, trail length, and its own glyph buffer; glyphs occasionally swap mid-stream. - **Rendering**: bright near-white leading glyph, green-to-dim trail via per-cell alpha fading, plus a translucent black overlay each frame for smooth motion trails. - **Recycling**: when a head plus its trail passes the bottom, the column is re-randomized above the screen — no accumulating state. - **Controls**: Pause/Resume (verified image freezes, then continues from the same frame) and Restart (verified full clear with no leftover trails). - **Resize**: on `resize`, canvas is resized and `setup()` rebuilds the column layout and repaints black — no stretched screenshot or uncovered strip. - All glyphs are katakana/digits drawn procedurally with the local `monospace` font; no external assets. Verified via motion sampling: independent column movement, bright heads, fading trails, freeze on pause, resume continuity, and Restart clearing. Resize behavior is implemented via the same verified `setup()` path but not visually exercised in-browser.