Reaction-diffusion · gemini-4-argon
Output generated Cost / run $0.1162 Runtime 200.0s
Prompt for this run
Build a Gray-Scott reaction-diffusion simulation on a 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 two chemical concentration fields, U and V, with diffusion and the Gray-Scott reaction, feed, and removal terms. Evolve these fields rather than displaying a prerecorded pattern. - Use a square simulation grid with wrapping boundaries. Choose stable time and spatial steps with parameters Du = 0.16, Dv = 0.08, feed = 0.035, and kill = 0.062 in simulation units. - Initially fill the field with U = 1 and V = 0, then seed a small central region with V and reduced U. Map concentrations to contrasting colors so evolving organic patterns are visible. - Clicking or dragging adds V and reduces U near the pointer. Provide Pause/Resume and Reset; Reset restores the initial fields and seed. - Choose Canvas 2D or WebGL, and bound grid resolution and work per frame to keep interaction responsive. Verify: Sample early field evolution, then seed a separate region with the pointer. Check that the added region affects the following frames. Pause and resume, then reset and compare the restored central seed with the initial scene.
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 · 27 messages
Build a Gray-Scott reaction-diffusion simulation on a 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 two chemical concentration fields, U and V, with diffusion and the Gray-Scott reaction, feed, and removal terms. Evolve these fields rather than displaying a prerecorded pattern. - Use a square simulation grid with wrapping boundaries. Choose stable time and spatial steps with parameters Du = 0.16, Dv = 0.08, feed = 0.035, and kill = 0.062 in simulation units. - Initially fill the field with U = 1 and V = 0, then seed a small central region with V and reduced U. Map concentrations to contrasting colors so evolving organic patterns are visible. - Clicking or dragging adds V and reduces U near the pointer. Provide Pause/Resume and Reset; Reset restores the initial fields and seed. - Choose Canvas 2D or WebGL, and bound grid resolution and work per frame to keep interaction responsive. Verify: Sample early field evolution, then seed a separate region with the pointer. Check that the added region affects the following frames. Pause and resume, then reset and compare the restored central seed with the initial scene.
thinking
**Analyzing Prompt Requirements** I'm currently dissecting the prompt, focusing on pinpointing core requirements for a Gray-Scott reaction-diffusion simulation. My priority is to create an `index.html` solution that's performant, visually appealing, and responsive. I am taking care to properly maintain these key requirements. **Defining Simulation Parameters** I've moved on to solidify the simulation's core parameters. I'm focusing on the concentration fields, U and V, and how they interact within the grid. I've selected specific values for diffusion, feed, and kill rates (`Du = 0.16`, `Dv = 0.08`, `feed = 0.035`, `kill = 0.062`). I'm also carefully considering the best Laplacian stencil for the simulation (9-point vs 5-point) and how to map these parameters appropriately. **Confirming Gray-Scott Parameters** I've confirmed the classic Gray-Scott parameterization. Using `Du = 0.16`, `Dv = 0.08`, `feed = 0.035`, and `kill = 0.062` with a 5-point Laplacian and `dt = 1.0` yields the expected mitosis/coral/soliton patterns. I am finalizing the initial conditions; setting U to 1 and V to 0 initially, with a central seed of `U = 0.50` and `V = 0.25`, and I will ensure that reset restores the exact initial fields. This will enable deterministic comparisons.
index.html (21826 bytes)Successfully wrote to index.html
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{"action":"inspect"}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":"Running\nStep: 156\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nPause\nReset\nBrush Radius\n10 px\nSteps / Frame\n12\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.9906\nMean V\n0.0037\nMax V\n0.3675\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
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**Refining Core Structure** Okay, I've adjusted the central seed's asymmetry. The goal is a more intricate break-up pattern, mimicking mitotic waves, but still retaining a clean core. I'm focusing on ensuring it unfolds rapidly and with complex structures as it expands. This tweak should accelerate the desired visual effect.
{"toY":260,"x":260,"toX":350,"y":200,"action":"drag"}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":"Running\nStep: 4632\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nPause\nReset\nBrush Radius\n10 px\nSteps / Frame\n12\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.9536\nMean V\n0.0166\nMax V\n0.3764\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
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**Observing Turing Patterns Evolve** I'm captivated by the organic Turing pattern evolution! The upper-left region is particularly interesting with its growth and curling. I'm moving on to testing Pause, Resume, and Reset buttons using `click` in the browser tool to understand the interactivity.
{"x":680,"y":230,"action":"click"}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":"Running\nStep: 20664\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nPause\nReset\nBrush Radius\n10 px\nSteps / Frame\n12\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.6055\nMean V\n0.1418\nMax V\n0.3858\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
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**Analyzing Coordinate Mismatch** I'm puzzled: the `x=680, y=230` click didn't pause. Now I'm checking the viewport's coordinates, especially for the "Pause" and "Reset" buttons within the 1200x800 resolution. I'm examining a screenshot to understand the app-shell's centering. I'll need the total width of `.app-shell` to progress.
{"action":"click","x":815,"y":182}Frame 1, +1ms
[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":"Paused\nStep: 25248\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nResume\nReset\nBrush Radius\n10 px\nSteps / Frame\n12\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.6000\nMean V\n0.1443\nMax V\n0.3850\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
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**Analyzing Button Positioning** I'm focusing on the discrepancy in the screenshot regarding the Pause/Reset button's Y-coordinate. It seems the `.app-shell`'s top is at y=15, and the buttons are around y=230. I'm puzzled why a click at x=815, y=182, would be interpreted as hitting the Pause or Reset button, given the button's apparent Y-position of 230. Perhaps there's an offset or another factor in play?
{"y":230,"x":960,"action":"click"}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":"Paused\nStep: 25248\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nResume\nReset\nBrush Radius\n10 px\nSteps / Frame\n12\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.6000\nMean V\n0.1443\nMax V\n0.3850\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
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**Analyzing Pixel Coordinates** I've made a breakthrough! I just realized the significance of the Reset button's x-coordinate. It's around x=800 in the screenshot. That's because the attached image is 1200x800. Let me measure the pixel coordinates in the attached image, and see where they lead.
{"x":680,"y":230,"action":"click"}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":"Paused\nStep: 25248\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nResume\nReset\nBrush Radius\n10 px\nSteps / Frame\n12\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.5978\nMean V\n0.1462\nMax V\n0.5000\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
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**Analyzing Pixel Scaling** I've made a key discovery: the bright spot's placement at (680, 230) on the scaled image stems from its original coordinates! The scaling from 1200x800 to 1000x667 is the culprit. I'm now working on the calculation: image coordinates * (1200/1000). I have an idea about where to go from here!
{"x":818,"y":278,"action":"click"}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":"Paused\nStep: 25248\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nResume\nReset\nBrush Radius\n10 px\nSteps / Frame\n6\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.5978\nMean V\n0.1462\nMax V\n0.5000\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
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**Identifying UI Element Locations** I've pinpointed the Pause/Resume button's coordinates as (815, 182). I also learned the "Steps/Frame" slider changed at (818, 278). Based on the layout, the Reset button is likely positioned at x = 960 and the same y coordinate as Pause. I'm building a more precise mapping of the UI now.
{"action":"click","x":815,"y":182}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":"Running\nStep: 25290\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nPause\nReset\nBrush Radius\n10 px\nSteps / Frame\n6\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.5979\nMean V\n0.1447\nMax V\n0.3850\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
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**Verifying Functionality** I've successfully resumed and am now verifying functionality. I'm focusing on comparing the restored central seed after a reset with the initial scene. I'm also making sure the reset function correctly restores `stepsPerFrame` to `DEFAULT_PARAMS.stepsPerFrame`, to avoid any unexpected behavior.
{"x":960,"y":182,"action":"click"}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":"Running\nStep: 48\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nPause\nReset\nBrush Radius\n10 px\nSteps / Frame\n6\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.9900\nMean V\n0.0037\nMax V\n0.3463\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
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**Refining Reset Functionality** I've just observed that the reset operation successfully restored the central seed and step count, as well as the U and V values, to their initial state. The step count reset to zero, we're at step 24 / 48 of the captured frames. I'm now focusing on a minor enhancement to the `resetBtn` handler, making sure it also restores `stepsPerFrame`.
{"edits":[{"oldText":" resetBtn.addEventListener('click', () => {\n params.Du = DEFAULT_PARAMS.Du;\n params.Dv = DEFAULT_Successfully replaced 1 block(s) in index.html.
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{"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":"Running\nStep: 108\nGray-Scott Reaction–Diffusion\n\nTwo chemical species U and V diffuse, react (U + 2V → 3V), replenish, and decay across a periodic torus grid.\n\nSIMULATION CONTROLS\nPause\nReset\nBrush Radius\n10 px\nSteps / Frame\n12\nPARAMETERS (SIM UNITS)\nDiffusion U (Du)\n0.160\nDiffusion V (Dv)\n0.080\nFeed Rate (f)\n0.035\nKill Rate (k)\n0.062\nDefault (0.035 / 0.062)\nCoral (0.055 / 0.062)\nFIELD DIAGNOSTICS\nMean U\n0.9919\nMean V\n0.0028\nMax V\n0.3211\nGrid Size\n200 × 200\nClick or drag on the canvas to inject chemical V and locally deplete U.","images":"attached"}
I have built the self-contained Gray-Scott reaction-diffusion simulation in `index.html`. ### Key Implementation Details - **Reaction–Diffusion Engine**: Maintains double-buffered `Float32Array` concentration fields `U` and `V` on a `200 × 200` periodic (wrapping) square grid using a 5-point discrete Laplacian with `dt = 1.0`, `Du = 0.16`, `Dv = 0.08`, `feed = 0.035`, and `kill = 0.062`. - **Initialization & Coloring**: Initializes the grid with `U = 1.0, V = 0.0` everywhere and seeds a deterministic central region with elevated `V` and reduced `U`. Concentrations map to a high-contrast multi-stop color gradient rendered via Canvas 2D `ImageData` with bounded steps per frame (`12` default, capped at `24`). - **Interactive Seeding & Controls**: Clicking or dragging on the canvas injects `V` and depletes `U` around the pointer with toroidal wrapping. Includes **Pause/Resume**, **Reset**, live parameter sliders, and real-time field diagnostics (`Mean U`, `Mean V`, `Max V`, and step count). ### Verification Summary - **Checked**: - Inspected initial scene and early field evolution (`Mean U`, `Mean V`, `Max V`, and expanding central ring). - Dragged across a separate upper-left region of the canvas and confirmed the newly seeded `V` region evolved into curling reaction-diffusion wave fronts alongside the central pattern. - Tested **Pause** and **Resume** controls, confirming simulation steps and field values froze while paused and continued evolving upon resume. - Tested **Reset**, confirming that the step counter, parameters, and central seed returned to the initial state. - Verified no runtime or console errors occurred. - **Unverified**: - Long-run behavior under extreme custom slider combinations outside the default and preset regimes.