​

function setup() {

  createCanvas(800, 800);

}

​

function draw() {

  noFill();

  background(20);

stroke(255);

  circle( width / 2, height / 2,400);

  for (let i = particles.length - 1; i >= 0; i--) {

    particles[i].update();

    particles[i].display();

    if (particles[i].isDead()) {

      particles.splice(i, 1);

    }

  }

​

  if (frameCount % 5 == 0) {

    // Emit a new particle every 5 frames

    const p = new Particle();

    particles.push(p);

  }

}

​

// Particle class

class Particle {

  constructor() {

    // Set the starting position of the particle

   this.x = width / 2;

    this.y = height/2;

​

    // Set the initial velocity of the particle

    this.velocity = createVector(random(-0.1, 0.1), random(-0.1, 0.1));

​

    // Set the life of the particle

    this.life = 256;

  }

​

  update() {

    // Gradually change the velocity of the particle towards the y direction

    this.velocity.y = lerp(this.velocity.y, -2, 0.05);

​

    // Update the position of the particle using the velocity vector

    this.x += this.velocity.x;

    this.y += this.velocity.y;

​

    // Decrease the life of the particle

    this.life -= 2;

  }

​

  display() {

    // Set the color of the particle

    fill(255, this.life);

​

    // Draw the particle

    ellipse(this.x, this.y, 5);

  }

​

  isDead() {

    // Return true if the particle's life is less than or equal to 0

    return this.life <= 0;

  }

}