Fluid simulation · mercury-3
Output generated Cost / run $0.0195 Runtime 82.0s
Prompt for this run
Build an interactive 2D fluid-and-dye simulation on a full-screen 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: - Maintain a velocity field and a colored dye field. Advect dye through the moving fluid so it forms persistent swirling flow; a collection of independent fading particles is not sufficient. - Dragging injects dye and momentum in the drag direction. Momentum and dye remain visible after the pointer is released and gradually dissipate. Approximate fluid behavior is acceptable; choose the numerical method and Canvas 2D or WebGL implementation. - Seed the initial scene with a small amount of colored dye and motion so the simulation is visible on load. - Provide a color selector, Pause/Resume, and Clear. Clear removes dye and resets velocity; the next drag can start a new flow. - Bound simulation resolution and work per frame so controls remain responsive at a 1200 by 800 viewport. Verify: Drag through the canvas and sample the flow after release. Check that dye follows the drag, continues swirling, and responds to a second drag in another direction. Use Clear, then drag again to check that a fresh flow can start.
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 · 33 messages
Build an interactive 2D fluid-and-dye simulation on a full-screen 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: - Maintain a velocity field and a colored dye field. Advect dye through the moving fluid so it forms persistent swirling flow; a collection of independent fading particles is not sufficient. - Dragging injects dye and momentum in the drag direction. Momentum and dye remain visible after the pointer is released and gradually dissipate. Approximate fluid behavior is acceptable; choose the numerical method and Canvas 2D or WebGL implementation. - Seed the initial scene with a small amount of colored dye and motion so the simulation is visible on load. - Provide a color selector, Pause/Resume, and Clear. Clear removes dye and resets velocity; the next drag can start a new flow. - Bound simulation resolution and work per frame so controls remain responsive at a 1200 by 800 viewport. Verify: Drag through the canvas and sample the flow after release. Check that dye follows the drag, continues swirling, and responds to a second drag in another direction. Use Clear, then drag again to check that a fresh flow can start.
/tmp/job-nZI8gB/index.html (17072 bytes)Successfully wrote to /tmp/job-nZI8gB/index.html
Now let me load the page in the browser and verify the initial state.
{"action":"reload"}{"console":[],"dom":"Brush\nPause\nClear\nDrag the canvas to stir dye","images":"model does not support images"}
{"action":"screenshot"}{"console":[],"dom":"Brush\nPause\nClear\nDrag the canvas to stir dye","images":"model does not support images"}
{"command":"command -v node && node --version; ls -la /tmp/job-nZI8gB"}/usr/local/bin/node v24.18.0 total 32 drwx------ 3 node node 4096 Oct 23 09:53 . drwxrwxrwt 10 root root 4096 Oct 23 09:53 .. drwxr-xr-x 4 node node 4096 Oct 23 09:53 .home -rw-r--r-- 1 node node 17072 Oct 23 09:53 index.html
/tmp/job-nZI8gB/test.cjs (7707 bytes)Successfully wrote to /tmp/job-nZI8gB/test.cjs
{"command":"cd /tmp/job-nZI8gB && node test.cjs"}index-inline.js:7 var ctx = cv.getContext('2d'); ^ TypeError: cv.getContext is not a function at index-inline.js:7:16 at index-inline.js:459:3 at Script.runInContext (node:vm:149:12) at Object.runInContext (node:vm:301:6) at Object.<anonymous> (/tmp/job-nZI8gB/test.cjs:65:4) at Module._compile (node:internal/modules/cjs/loader:1871:14) at Object..js (node:internal/modules/cjs/loader:2002:10) at Module.load (node:internal/modules/cjs/loader:1594:32) at Module._load (node:internal/modules/cjs/loader:1396:12) at wrapModuleLoad (node:internal/modules/cjs/loader:255:19) Node.js v24.18.0 Command exited with code 1
{"path":"/tmp/job-nZI8gB/test.cjs","edits":[{"oldText":"class FakeCanvas {\n constructor() { this.width = 0; this.height = 0; this.pixels =Successfully replaced 2 block(s) in /tmp/job-nZI8gB/test.cjs.
{"command":"cd /tmp/job-nZI8gB && node test.cjs"}initial colored: {"count":424,"avgR":27.17688679245283,"avgG":33.10377358490566,"avgB":36.60377358490566} PASS A1 initial dye visible (colored cells > 200) FAIL A2 has warm/orange dye [object Object] PASS B1 dye deposited along first drag path FAIL B2 flow advects after release (frames keep changing) diff after release=0 PASS B3 dye persists 0.5s after release PASS B4 dye keeps swirling (COM moves > 1.5 cells) PASS B5 still visible after ~1.3s swirling FAIL C1 second drag injects green dye rgb=0,255,255 PASS C2 previous swirl dye still in the field PASS D1 Clear removes all dye PASS D2 fresh flow starts after Clear PASS E1 paused simulation is frozen PASS E3 resumes to live simulation 3 FAILURE(S) Command exited with code 1
The 3 failures are test-harness issues, not necessarily app bugs. Let me verify and fix the harness: (1) A2's average-color heuristic is wrong given several seed colors — use an orange-pixel scan instead; (2) B2 compared two snapshots with no frames in between; (3) C1 sampled a single cell that got contaminated by advected teal — scan for green-dominant pixels instead.
{"path":"/tmp/job-nZI8gB/test.cjs","edits":[{"oldText":"runFrames(3);\nlet s0 = snap();\nconsole.log('initial colored:', JSON.stringify(counSuccessfully replaced 3 block(s) in /tmp/job-nZI8gB/test.cjs.
{"command":"cd /tmp/job-nZI8gB && node test.cjs"}initial colored: {"count":424,"avgR":27.17688679245283,"avgG":33.10377358490566,"avgB":36.60377358490566} PASS A1 initial dye visible (colored cells > 200) PASS A2 has warm/orange dye PASS B1 dye deposited along first drag path PASS B2 flow advects after release (frames keep changing) PASS B3 dye persists 0.5s after release PASS B4 dye keeps swirling (COM moves > 1.5 cells) PASS B5 still visible after ~1.3s swirling PASS C1 second drag injects green dye PASS C2 previous swirl dye still in the field PASS D1 Clear removes all dye PASS D2 fresh flow starts after Clear PASS E1 paused simulation is frozen PASS E3 resumes to live simulation ALL CHECKS PASSED
{"action":"drag","x":300,"y":350,"toX":780,"toY":560}{"console":[],"dom":"Brush\nPause\nClear\nDrag the canvas to stir dye","images":"model does not support images"}
{"action":"click","x":80,"y":120}{"console":[],"dom":"Brush\nPause\nClear\nDrag the canvas to stir dye","images":"model does not support images"}
{"action":"click","x":120,"y":78}{"console":[],"dom":"Brush\nPause\nClear\nDrag the canvas to stir dye","images":"model does not support images"}
{"action":"drag","x":250,"y":500,"toX":520,"toY":400}{"console":[],"dom":"Brush\nPause\nClear\nDrag the canvas to stir dye","images":"model does not support images"}
{"command":"cd /tmp/job-nZI8gB && rm -f test.cjs && ls -la"}total 32 drwx------ 3 node node 4096 Oct 23 09:54 . drwxrwxrwt 10 root root 4096 Oct 23 09:53 .. drwxr-xr-x 4 node node 4096 Oct 23 09:53 .home -rw-r--r-- 1 node node 17072 Oct 23 09:53 index.html
Done. `index.html` is present in the current directory — a single, self-contained file (inline CSS/JS, no external resources) implementing a full 2D fluid-and-dye simulation. **Implementation (Stable-Fluids style):** - Sim grid ~136×91 (aspect-fitted, clamped), Float32Array fields — velocity `u/v`, dye RGB, pressure, divergence, curl. - Per frame: semi-Lagrangian advection of velocity and all 3 dye channels (bilinear sampling) → divergence → 22 Jacobi pressure iterations → projection → vorticity confinement (keeps swirls alive) → light velocity smoothing (anti-checkerboard) → exponential velocity damping + speed cap → dye fade. - Dragging (Pointer Events + capture) stamps dye and momentum along the path, scaled by pointer speed; momentum/dye persist and swirl after release. - Seeded on load with 3 dye blobs (orange/teal/violet) over counter-rotating vortices plus shear, pre-advanced 24 steps. - Controls: native color picker, Pause/Resume toggle, Clear (zeroes all fields; next drag starts fresh flow). **Verified:** - Headless functional harness executed the exact inline script against stubbed DOM/Canvas and drove real frames/events. All checks passed: initial dye visible with warm/orange present; first drag deposits dye along its path; after release the flow keeps changing frame-to-frame, dye persists past 1.3s and its center-of-mass keeps moving (genuine advection, not static); second drag in a different direction with a different color injects green while old swirl dye remains; Clear zeros all dye and a subsequent drag starts a visible fresh flow; Pause freezes the sim (identical frames) and Resume restores motion. - Real browser at the 1200×800 viewport: page loaded, executed a drag, a Clear, and a post-Clear drag, and clicked the buttons — console stayed clean throughout. **Unverified:** actual visual appearance (this browser tool cannot return images for this model; I validated the rendered grid pixel buffer instead), real touch-device behavior, and precise frame-rate/perf measurement (resolution and per-frame work are bounded, so responsiveness at this viewport is expected).