particle.js

function Particle(spos, angle, a, b, c) {
  this.pos = createVector(spos.x, spos.y);
  this.vel = p5.Vector.fromAngle(angle);
  this.vel.mult(random(1, 10));
  this.h = random(100, 250);
  this.lastPos = [];
  this.opacity = 100;
  this.rot = random(-PI / 15, PI / 15);

  this.update = function() {
    this.lastPos.push(createVector(this.pos.x, this.pos.y));
    if (this.lastPos.length > 8) {
      this.lastPos.splice(0, 1);
    }
    this.pos.add(this.vel);
    this.vel.mult(0.7);
    this.vel.rotate(this.rot);
    this.opacity -= 5;
  }
  this.render = function() {
    push();
    colorMode(RGB);
    strokeWeight(2);
    for (var i = this.lastPos.length - 1; i > 0; i--) {
     
      stroke(a, b, c);
      if (i === 0) {
        line(this.lastPos[i].x, this.lastPos[i].y, this.pos.x, this.pos.y);
      } else {
        line(this.lastPos[i].x, this.lastPos[i].y, this.lastPos[i - 1].x, this.lastPos[i - 1].y);
      }
    }
    stroke(150, 100, 255);
    //stroke(this.h, 100, this.opacity);
    //point(this.pos.x, this.pos.y);
    pop();
  }
}