Processing simple attractor

2015-12-14

by schrodingers

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/processing.js/1.4.13/processing.min.js"></script>
<canvas></canvas>

CSS

</style> <script type="text/javascript"> window.addEventListener('load', function() {
    var scripts=document.body.getElementsByTagName('script');
    var canvases=document.body.getElementsByTagName('canvas');
    new Processing(canvases[0], scripts[0].text);
}
, false);
 // Here prevent javascript in body from throwing error </script> <style>

JavaScript

/*
 title: simple attractor
 date: 2015-12-14
 */

color[] spring = {#ff6699, #ff9900, #ffcc00, #9adb1b, #00cc66, #00cccc, #00ccff, #6633cc, #ff66cc
};
PGraphics pg;

ArrayList <Part> ps = new ArrayList();
void setup() {
    size(800, 600);
   // for (int i = 0; i < 50; i++) {
   //     ps.add(new Part());
  //  }
}

void draw() {
    fill(44, 98);
    rect(0, 0, width, height);
	//loadPixels();
    //pixels[width * height * 4];
    //updatePixels();
            ps.add(new Part());

    for (int i=ps.size()-1; i>1; i--){
		Particle p = ps.get(i);
        if (p.life <= 1){
        ps.remove(p);}
        p.display();
        p.update();
    }
}

class Part {
    float x, y; // rest position
    float vx, vy; // velocity
float mass, drag, dt, forceStr;
    float rad; // radius
    int col;
	float life;

    Part() {
        x = mouseX + 10 * random(-TAU, TAU);
        y = mouseY + 10 * random(0, TAU);
        vx = 0;
        vy = random(0,-1.9);
        mass = random(0.3, 1.0);
        dt = 0.09;
        drag = 0.041;
        forceStr = 0.05;
        rad = randomGaussian() * 10 ; // radius
		life = 300;
        col = spring[(int) random(0, spring.length - 1)];
    }

    void display() {
        noStroke();
        fill(col, life);
        ellipse(x, y, rad, rad);
    }

    void update() {
    
            dx = mouseX - x;
            dy = mouseY - y;
            float fx = (dx * forceStr) - (drag*vx);  float fy = (dy * forceStr) - (drag*vy);
            vx += fx * dt/mass;
            vy += fy * dt/mass;
            x+=vx*dt;
            y+=vy*dt;
           life--;
            


    }

}