99 lines, 3 of them comments · 779 tokens, written in 6 seconds for $0.0022

 1  let particles = [];
 2  
 3  class Particle {
 4    constructor(x, y) {
 5      this.pos = createVector(x, y);
 6      this.vel = createVector(random(-3, 3), random(-8, -2));
 7      this.acc = createVector(0, 0);
 8      this.life = 255;
 9      this.hue = random(0, 360);
10      this.size = random(4, 12);
11    }
12  
13    applyForce(force) {
14      this.acc.add(force);
15    }
16  
17    update() {
18      let mouse = createVector(mouseX, mouseY);
19      let dir = p5.Vector.sub(mouse, this.pos);
20      let d = dir.mag();
21      if (d > 0) {
22        dir.normalize();
23        let force = dir.mult(0.2);
24        this.applyForce(force);
25      }
26  
27      this.vel.add(this.acc);
28      this.vel.limit(6);
29      this.pos.add(this.vel);
30      this.acc.mult(0);
31  
32      this.life -= 3;
33      this.vel.y += 0.15; // gravity
34    }
35  
36    edges() {
37      if (this.pos.x < 0 || this.pos.x > width) this.vel.x *= -0.8;
38      if (this.pos.y > height) {
39        this.pos.y = height;
40        this.vel.y *= -0.7;
41      }
42    }
43  
44    show() {
45      colorMode(HSB);
46      noStroke();
47      fill(this.hue, 90, 100, this.life / 255);
48      circle(this.pos.x, this.pos.y, this.size);
49      colorMode(RGB);
50    }
51  
52    isDead() {
53      return this.life < 0;
54    }
55  }
56  
57  function setup() {
58    createCanvas(640, 480);
59    colorMode(HSB);
60  }
61  
62  function draw() {
63    background(20, 20, 30, 40);
64  
65    // Add new particles continuously
66    if (frameCount % 2 === 0) {
67      for (let i = 0; i < 3; i++) {
68        particles.push(new Particle(width / 2 + random(-40, 40), height - 20));
69      }
70    }
71  
72    for (let i = particles.length - 1; i >= 0; i--) {
73      let p = particles[i];
74      p.update();
75      p.edges();
76      p.show();
77      if (p.isDead()) {
78        particles.splice(i, 1);
79      }
80    }
81  
82    // Draw emitter
83    fill(200, 30, 100);
84    noStroke();
85    rect(width / 2 - 30, height - 30, 60, 20, 5);
86  }
87  
88  function mousePressed() {
89    for (let i = 0; i < 60; i++) {
90      let p = new Particle(mouseX, mouseY);
91      p.vel = createVector(random(-7, 7), random(-9, -3));
92      p.life = 180;
93      particles.push(p);
94    }
95  }
96  
97  function windowResized() {
98    resizeCanvas(640, 480);
99  }