Flow-field particles · qwen3.6-flash
Output generated Cost / run $0.0105 Runtime 29.1s
Prompt for this run
Using the pre-provided p5.min.js (global p5, instance or global mode), create a full-screen flow-field particle animation: thousands of particles advected by Perlin-noise vectors, leaving fading trails, with colors shifting over time.
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 · 16 messages
Using the pre-provided p5.min.js (global p5, instance or global mode), create a full-screen flow-field particle animation: thousands of particles advected by Perlin-noise vectors, leaving fading trails, with colors shifting over time.
thinking
The user wants a full-screen flow-field particle animation using p5.js. I need to: 1. Use the pre-provided p5.min.js file (load it via `<script src="p5.min.js">`) 2. Create a single-page HTML with CSS in `<style>` and JS in `<script>` 3. Build a flow-field particle animation with: - Thousands of particles - Perlin noise vectors advecting them - Fading trails - Colors shifting over time - Full screen Let me first check that p5.min.js exists in the current directory, then write the index.html file.
{"command":"ls /tmp/ws/p5.min.js"}/tmp/ws/p5.min.js
thinking
The file exists. Let me create a full-screen flow-field particle animation using p5.min.js. I'll use global mode with setup() and draw() functions, Perlin noise for flow field vectors, thousands of particles, fading trails, and color shifting over time.
/tmp/ws/index.html (4104 bytes)Successfully wrote 4104 bytes to /tmp/ws/index.html
thinking
The user wants me to build a single-page web app with flow-field particle animation using p5.min.js. Let me create the index.html file that includes: 1. A full-screen canvas 2. Perlin noise-based flow field 3. Thousands of particles advected by the noise vectors 4. Fading trails (drawn via semi-transparent overlay) 5. Colors shifting over time (using HSB color mode with cycling hue) Let me write a complete self-contained HTML file with inline CSS and JS, loading p5.min.js from the local directory.
Now let me review it for correctness — particularly the `set`/`fill` usage since `fill` in HSB should accept 4 values: [h, s, b, a].
{"path":"/tmp/ws/index.html"}<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Flow Field Particles</title> <style> * { margin: 0; padding: 0; box-sizing: border-box; } html, body { overflow: hidden; width: 100%; height: 100%; background: #000; } canvas { display: block; } </style> </head> <body> <script src="p5.min.js"></script> <script> // ─── Configuration ─── const PARTICLE_COUNT = 5000; const TRAIL_FADE = 0.045; // alpha of overlay each frame (lower = longer trails) const NOISE_SCALE = 0.003; // spatial frequency of Perlin noise const TIME_SCALE = 0.00025; // temporal frequency — how fast the field morphs const COLOR_SPEED = 0.0006; // how fast hues shift const MAX_STEPS = 3; // steps per frame between draws const STEP_LEN = 3; // length per step const BASE_HUE = 0; // starting hue (will cycle) const HUE_RANGE = 360; // full spectrum cycling const SATURATION = 80; // saturation % const BRIGHTNESS = 90; // brightness % let particles = []; let timeOffset; class Particle { constructor() { this.x = random(width); this.y = random(height); this.vx = 0; this.vy = 0; // slight hue offset per particle so they don't all look identical this.hueOffset = random(HUE_RANGE); // velocity smoothing factor (0 = instant turn, 1 = no turning) this.smooth = random(0.7, 0.98); } update(tBase) { // Sample Perlin noise for direction at current position + time let angle = noise( this.x * NOISE_SCALE, this.y * NOISE_SCALE, tBase ) * TAU * 2; // Blend new desired velocity with current for smoothness let targetVx = cos(angle) * STEP_LEN; let targetVy = sin(angle) * STEP_LEN; this.vx = lerp(this.vx, targetVx, 1 - this.smooth); this.vy = lerp(this.vy, targetVy, 1 - this.smooth); this.x += this.vx; this.y += this.vy; // Wrap around edges with a margin const m = 20; if (this.x < -m) this.x = width + m; if (this.x > width + m) this.x = -m; if (this.y < -m) this.y = height + m; if (this.y > height + m) this.y = -m; } draw(tBase) { // Each particle gets its own hue shifted from the base let h = (BASE_HUE + tBase * COLOR_SPEED * 1000 + this.hueOffset) % HUE_RANGE; stroke(h, SATURATION, BRIGHTNESS, 120); point(this.x, this.y); } } function setup() { createCanvas(windowWidth, windowHeight); colorMode(HSB, HUE_RANGE, 100, 100, 100); strokeWeight(1.2); // Warm white background fill that will be faded out each frame background(0, 0, 0, 100); timeOffset = random(10000); // Initialize particles for (let i = 0; i < PARTICLE_COUNT; i++) { particles.push(new Particle()); } } function draw() { // Fade the entire canvas to create trails // Using the HSB backdrop — semi-transparent black creates fading trails set(0, 0, [0, 0, 0, map(TRAIL_FADE, 0, 1, 0, 255)]); noStroke(); fill(0, 0, 0, TRAIL_FADE * 255); rect(0, 0, width, height); let tBase = millis() * 0.001 + timeOffset; // For performance: render in batches using group drawing technique isn't available // So we just update and draw each particle directly // With 5000 particles, limit steps to keep framerate up for (let i = 0; i < particles.length; i++) { // Take multiple small steps through the noise field for (let s = 0; s < MAX_STEPS; s++) { particles[i].update(tBase + s * 0.01); } particles[i].draw(tBase); } } function windowResized() { resizeCanvas(windowWidth, windowHeight); // Reset background on resize background(0, 0, 0, 100); } </script> </body> </html>
thinking
The code looks good but I want to fix a couple of issues: 1. The `set()` call and `fill()` with alpha in HSB mode needs to work correctly - the fill should be black (hue 0, saturation 0, brightness 0, alpha = TRAIL_FADE * 255). 2. Let me remove the unused `TIME_SCALE` constant 3. I should also verify that using `strokeWeight(1.2)` with `point()` works as expected - p5's `point()` respects strokeWeight. Let me refine the file slightly - clean up the unused constant and make sure the trail fade is correct.
I see a minor issue — an unused `TIME_SCALE` variable. Let me clean that up and ensure the trail-fade logic is bulletproof:
{"path":"/tmp/ws/index.html","edits":[{"oldText":" const TIME_SCALE = 0.00025; // temporal frequency — how fast the field morphs","nSuccessfully replaced 2 block(s) in /tmp/ws/index.html.
Now verify the final file is complete:
{"path":"/tmp/ws/index.html"}<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Flow Field Particles</title> <style> * { margin: 0; padding: 0; box-sizing: border-box; } html, body { overflow: hidden; width: 100%; height: 100%; background: #000; } canvas { display: block; } </style> </head> <body> <script src="p5.min.js"></script> <script> // ─── Configuration ─── const PARTICLE_COUNT = 5000; const TRAIL_FADE = 0.045; // alpha of overlay each frame (lower = longer trails) const NOISE_SCALE = 0.003; // spatial frequency of Perlin noise const COLOR_SPEED = 0.0006; // how fast hues shift const MAX_STEPS = 3; // steps per frame between draws const STEP_LEN = 3; // length per step const BASE_HUE = 0; // starting hue (will cycle) const HUE_RANGE = 360; // full spectrum cycling const SATURATION = 80; // saturation % const BRIGHTNESS = 90; // brightness % let particles = []; let timeOffset; class Particle { constructor() { this.x = random(width); this.y = random(height); this.vx = 0; this.vy = 0; // slight hue offset per particle so they don't all look identical this.hueOffset = random(HUE_RANGE); // velocity smoothing factor (0 = instant turn, 1 = no turning) this.smooth = random(0.7, 0.98); } update(tBase) { // Sample Perlin noise for direction at current position + time let angle = noise( this.x * NOISE_SCALE, this.y * NOISE_SCALE, tBase ) * TAU * 2; // Blend new desired velocity with current for smoothness let targetVx = cos(angle) * STEP_LEN; let targetVy = sin(angle) * STEP_LEN; this.vx = lerp(this.vx, targetVx, 1 - this.smooth); this.vy = lerp(this.vy, targetVy, 1 - this.smooth); this.x += this.vx; this.y += this.vy; // Wrap around edges with a margin const m = 20; if (this.x < -m) this.x = width + m; if (this.x > width + m) this.x = -m; if (this.y < -m) this.y = height + m; if (this.y > height + m) this.y = -m; } draw(tBase) { // Each particle gets its own hue shifted from the base let h = (BASE_HUE + tBase * COLOR_SPEED * 1000 + this.hueOffset) % HUE_RANGE; stroke(h, SATURATION, BRIGHTNESS, 120); point(this.x, this.y); } } function setup() { createCanvas(windowWidth, windowHeight); colorMode(HSB, HUE_RANGE, 100, 100, 100); strokeWeight(1.2); // Warm white background fill that will be faded out each frame background(0, 0, 0, 100); timeOffset = random(10000); // Initialize particles for (let i = 0; i < PARTICLE_COUNT; i++) { particles.push(new Particle()); } } function draw() { // Fade the entire canvas to create trails // Using the HSB backdrop — semi-transparent black creates fading trails set(0, 0, [0, 0, 0, map(TRAIL_FADE, 0, 1, 0, 255)]); noStroke(); fill(0, 0, 0, TRAIL_FADE * 255); rect(0, 0, width, height); let tBase = millis() * 0.001 + timeOffset; for (let i = 0; i < particles.length; i++) { // Take multiple small steps through the noise field for (let s = 0; s < MAX_STEPS; s++) { particles[i].update(tBase + s * 0.01); } particles[i].draw(tBase); } } function windowResized() { resizeCanvas(windowWidth, windowHeight); // Reset background on resize background(0, 0, 0, 100); } </script> </body> </html>
thinking
The file looks good. Let me verify the logic is correct: 1. **5000 particles** - each with random position, slight hue offset, and velocity smoothing 2. **Perlin noise field** - 3D (x, y, time) for spatially coherent flowing direction that morphs over time 3. **Velocity smoothing** - lerp between current and target velocity for smooth turns 4. **Fading trails** - each frame draws a semi-transparent black rect over the whole canvas before drawing new particles 5. **Color cycling** - HSB color mode with base hue that shifts over time + per-particle hue offsets 6. **Edge wrapping** - particles wrap around with margin so they don't bunch up at edges 7. **Multiple steps per frame** - each particle takes 3 small steps through the noise field per frame 8. **Responsive** - handles window resize One thing I want to check - in p5.js global mode with `colorMode(HSB, 360, 100, 100, 100)`, the `set()` function usage might not work correctly since `set()` uses the pixel array directly without the current colorMode transformation. The `set(0, 0, [r, g, b, a])` call should be in RGB/normal mode values. Since we set fill to `(0, 0, 0, TRAIL_FADE * 255)` which is HSB values where h=0, s=0, b=0 means black, and alpha = TRAIL_FADE * 255, this should produce a dark overlay creating the fade effect. This is actually correct because the fill() will be black in HSB space (h=0,s=0,b=0 = black), and the alpha creates transparency. Actually, wait - there's an issue with `set(0, 0, ...)`. The `set()` function doesn't use the current colorMode - it expects pixel colors as arrays. So `set(0, 0, [0, 0, 0, map(TRAIL_FADE, 0, 1, 0, 255)])` would interpret those as RGBA directly. But this only sets one pixel - then we draw a semi-transparent black rect on top. The single pixel `set` is basically useless here and could potentially cause issues. Let me remove it since the `fill` + `rect` approach already handles the fading. Also, I realize the `fill(0, 0, 0, ...)` in HSB mode with saturation=0 gives black regardless of hue, so this works correctly for the fade effect. Let me clean up by removing the unnecessary `set()` call.
I notice the `set()` call is doing nothing useful — only one pixel is set before the full-screen `rect()` draw. Let me clean that up:
{"path":"/tmp/ws/index.html","edits":[{"oldText":" // Fade the entire canvas to create trails\n // Using the HSB backdrop — semi-tSuccessfully replaced 1 block(s) in /tmp/ws/index.html.
thinking
Now let me verify the final version of the file is complete and correct.
{"path":"/tmp/ws/index.html"}<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Flow Field Particles</title> <style> * { margin: 0; padding: 0; box-sizing: border-box; } html, body { overflow: hidden; width: 100%; height: 100%; background: #000; } canvas { display: block; } </style> </head> <body> <script src="p5.min.js"></script> <script> // ─── Configuration ─── const PARTICLE_COUNT = 5000; const TRAIL_FADE = 0.045; // alpha of overlay each frame (lower = longer trails) const NOISE_SCALE = 0.003; // spatial frequency of Perlin noise const COLOR_SPEED = 0.0006; // how fast hues shift const MAX_STEPS = 3; // steps per frame between draws const STEP_LEN = 3; // length per step const BASE_HUE = 0; // starting hue (will cycle) const HUE_RANGE = 360; // full spectrum cycling const SATURATION = 80; // saturation % const BRIGHTNESS = 90; // brightness % let particles = []; let timeOffset; class Particle { constructor() { this.x = random(width); this.y = random(height); this.vx = 0; this.vy = 0; // slight hue offset per particle so they don't all look identical this.hueOffset = random(HUE_RANGE); // velocity smoothing factor (0 = instant turn, 1 = no turning) this.smooth = random(0.7, 0.98); } update(tBase) { // Sample Perlin noise for direction at current position + time let angle = noise( this.x * NOISE_SCALE, this.y * NOISE_SCALE, tBase ) * TAU * 2; // Blend new desired velocity with current for smoothness let targetVx = cos(angle) * STEP_LEN; let targetVy = sin(angle) * STEP_LEN; this.vx = lerp(this.vx, targetVx, 1 - this.smooth); this.vy = lerp(this.vy, targetVy, 1 - this.smooth); this.x += this.vx; this.y += this.vy; // Wrap around edges with a margin const m = 20; if (this.x < -m) this.x = width + m; if (this.x > width + m) this.x = -m; if (this.y < -m) this.y = height + m; if (this.y > height + m) this.y = -m; } draw(tBase) { // Each particle gets its own hue shifted from the base let h = (BASE_HUE + tBase * COLOR_SPEED * 1000 + this.hueOffset) % HUE_RANGE; stroke(h, SATURATION, BRIGHTNESS, 120); point(this.x, this.y); } } function setup() { createCanvas(windowWidth, windowHeight); colorMode(HSB, HUE_RANGE, 100, 100, 100); strokeWeight(1.2); // Warm white background fill that will be faded out each frame background(0, 0, 0, 100); timeOffset = random(10000); // Initialize particles for (let i = 0; i < PARTICLE_COUNT; i++) { particles.push(new Particle()); } } function draw() { // Semi-transparent black overlay creates the fading-trail effect noStroke(); fill(0, 0, 0, map(TRAIL_FADE, 0, 1, 0, 255)); rect(0, 0, width, height); let tBase = millis() * 0.001 + timeOffset; for (let i = 0; i < particles.length; i++) { // Take multiple small steps through the noise field for (let s = 0; s < MAX_STEPS; s++) { particles[i].update(tBase + s * 0.01); } particles[i].draw(tBase); } } function windowResized() { resizeCanvas(windowWidth, windowHeight); // Reset background on resize background(0, 0, 0, 100); } </script> </body> </html>
thinking
The file looks good. Let me verify it's properly formed and complete. The index.html is written at /tmp/ws/index.html. Let me summarize what this creates: - A full-screen canvas using p5.js (loaded from the local p5.min.js) - 5000 particles that move through a Perlin noise flow field - Fading trails via semi-transparent black overlay each frame - HSB color mode with hues cycling over time, each particle having its own hue offset for variety - Velocity smoothing so particles turn gradually rather than instantly - Edge wrapping with margin so particles re-enter from the opposite side - Multiple sub-steps per frame for smoother curves - Responsive to window resize This should be a beautiful flowing particle animation. The file is self-contained with inline CSS and JS, only loading p5.min.js from the local directory.
Done! `index.html` is ready at `/tmp/ws/index.html`. Here's what it does: **Flow Field Particle Animation** — 5,000 particles advected by a 3D Perlin-noise vector field (x, y, time). Key features: - **Perlin noise flow field**: Each particle samples `noise(x*scaled, y*scaled, t)` to determine its direction angle (`hue * 2π`), creating organic swirling patterns - **Fading trails**: Every frame a semi-transparent black rectangle overlays the canvas, causing older particle marks to gradually fade - **Color shifting in HSB**: Particles use HSB color with hue cycling globally over time + per-particle hue offsets for visual variety (saturation 80%, brightness 90%) - **Velocity smoothing**: Particles blend their desired velocity toward new target velocity via `lerp`, producing smooth curved paths instead of jagged turns - **Edge wrapping**: Particles wrap around with a 20px margin so they never "die" at edges - **Multiple sub-steps** (3 per frame, 3px each) for fluid-looking motion - **Responsive**: Auto-resizes on window change