Flow-field particles · qwen3.5-9b

I need to build a flow-field particle animation using p5.js. Let me break down the requirements:

1. Full-screen animation with at least 2,000 particles
2. Motion guided by smoothly varying Perlin-noise vector field
3. Nearby particles should follow locally coherent directions
4. Fading trails and varying particle colors over time
5. Evolve the field gradually (not repeating a short recorded sequence)
6. Recycle particles at canvas boundaries
7. Keep particle population bounded
8. Avoid allocating ever-growing trail history
9. Pause/Resume and Restart controls
10. Fit viewport at 1200x800
11. Choose palette, field scale, and particle speed freely
12. Use provided p5.min.js locally (no external resources)

First, let me check what files are available in the current directory.

Good, I have p5.min.js available. Now I need to create the flow-field particle animation. Let me design this:

1. **Flow Field Animation**: A flow field uses a vector field to guide particle motion. Each particle follows the direction of the vector at its position.

2. **Perlin Noise**: I'll use p5's built-in noise() function for Perlin noise to generate the vector field.

3. **Particle System**:
   - At least 2,000 particles
   - Each particle has position (x, y), velocity, and color
   - Particles follow the noise-based vector field
   - Fading trails (using alpha blending)
   - Colors vary over time

4. **Controls**:
   - Pause/Resume
   - Restart (clears trails and reinitializes particles)

5. **Technical considerations**:
   - Use instance mode for p5 to avoid conflicts
   - Fit to 1200x800 viewport
   - Recycle particles at boundaries
   - Use a fixed-size array for trails (not growing indefinitely)

Let me write the code:

```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 Particle Animation</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        body {
            overflow: hidden;
            background: #000;
        }
        canvas {
            display: block;
        }
        #controls {
            position: fixed;
            top: 10px;
            left: 10px;
            z-index: 100;
            background: rgba(0, 0, 0, 0.7);
            padding: 10px 15px;
            border-radius: 8px;
            color: white;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        #controls button {
            margin-right: 10px;
            padding: 8px 16px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            font-size: 14px;
            transition: all 0.2s;
        }
        #controls button:hover {
            transform: scale(1.05);
        }
        #controls button.active {
            background: #4CAF50;
        }
        #controls button:not(.active) {
            background: #2196F3;
        }
        #controls button#restart {
            background: #FF9800;
        }
        .info {
            margin-top: 10px;
            font-size: 12px;
            color: #aaa;
        }
    </style>
</head>
<body>
    <div id="controls">
        <button id="pauseBtn">Pause</button>
        <button id="restartBtn">Restart</button>
        <div class="info">
            Particles: <span id="particleCount">0</span> | 
            FPS: <span id="fps">0</span>
        </div>
    </div>
    <script src="p5.min.js"></script>
    <script>
        // Flow Field Particle Animation
        const canvas = new p5();
        
        canvas.setup = function() {
            canvas.createCanvas(1200, 800);
            canvas.pixelDensity(1);
            initParticles();
        };
        
        canvas.windowResized = function() {
            canvas.resizeCanvas(1200, 800);
        };
        
        // Particle class
        class Particle {
            constructor(x, y) {
                this.pos = p5.Vector.random2D().mult(2);
                this.vel = p5.Vector.random2D().mult(0.5);
                this.acc = p5.Vector.random2D().mult(0.1);
                this.history = [];
                this.maxHistory = 10;
                this.color = this.randomColor();
                this.age = 0;
            }
            
            randomColor() {
                const hue = (canvas.frameCount * 0.1 + this.pos.x * 0.01) % 360;
                return p5.Color.hsb(hue, 80, 100);
            }
            
            update() {
                this.vel.add(this.acc);
                this.vel.limit(2);
                this.pos.add(this.vel);
                this.acc.mult(0);
                this.age++;
                this.color = this.randomColor();
            }
            
            applyForce(force) {
                this.vel.add(force);
            }
            
            followField() {
                const angle = canvas.noise(this.pos.x * 0.01, this.pos.y * 0.01, canvas.frameCount * 0.001);
                this.vel.setAngle(angle);
            }
            
            edges() {
                if (this.pos.x > canvas.width) {
                    this.pos.x = 0;
                } else if (this.pos.x < 0) {
                    this.pos.x = canvas.width;
                }
                if (this.pos.y > canvas.height) {
                    this.pos.y = 0;
                } else if (this.pos.y < 0) {
                    this.pos.y = canvas.height;
                }
            }
            
            display() {
                canvas.noStroke();
                canvas.fill(this.color);
                canvas.ellipse(this.pos.x, this.pos.y, 2);
            }
        }
        
        // Particle system
        const particles = [];
        const maxParticles = 2000;
        
        function initParticles() {
            particles.length = 0;
            for (let i = 0; i < maxParticles; i++) {
                particles.push(new Particle(
                    canvas.random(0, canvas.width),
                    canvas.random(0, canvas.height)
                ));
            }
        }
        
        function draw() {
            canvas.background(0, 20);
            
            for (let particle of particles) {
                particle.followField();
                particle.update();
                particle.edges();
                particle.display();
            }
        }
        
        // Controls
        document.getElementById('pauseBtn').addEventListener('click', function() {
            canvas.loop = !canvas.loop;
            this.textContent = canvas.loop ? 'Pause' : 'Resume';
            this.classList.toggle('active');
        });
        
        document.getElementById('restartBtn').addEventListener('click', function() {
            initParticles();
        });
        
        // FPS counter
        let lastTime = 0;
        let frameCount = 0;
        
        canvas.draw = function() {
            const now = canvas.frameCount;
            if (now - lastTime >= 1000) {
                document.getElementById('fps').textContent = frameCount;
                frameCount = 0;
                lastTime = now;
            }
            frameCount++;
            draw();
        };
        
        // Start
        canvas.loop();
    </script>
</body>
</html>
```

I'm building a flow field animation with 2,000 particles that follow a Perlin noise vector field. The particles have fading trails, varying colors, and recycle at canvas boundaries. I'll add Pause/Resume and Restart controls, and ensure the animation fits a 1200x800 viewport.

The particle system uses Perlin noise to generate smooth, evolving vector fields. Each particle tracks its position and velocity, with colors shifting over time based on frame count and position. I'm implementing edge detection to recycle particles that move off-screen, and using a fixed-size array to manage the particle population efficiently.

I need to refine the noise-based vector field generation and ensure the particle motion feels organic and fluid. The key is creating a dynamic noise field that changes over time while maintaining coherent particle movement patterns.

Now let me run the application in the browser to inspect the output and verify the behavior.

Let me try with python instead.

Let me check what's available.

Node is available. Let me use it to serve the file.

Port 8080 is already in use. Let me try a different port.

Good, the server is running. Now let me open the browser and inspect the animation.

Let me try wget or use the browser tool directly.

Let me try a different approach - use the browser tool to inspect the page.

The animation is not working - the canvas is black and particles count is 0. The warning says p5.js was imported multiple times. I need to fix the HTML file. Let me read it and check the structure.