​

function Particle() {

  this.pos = createVector(random(width), random(height));

  this.vel = createVector(0,0);

  this.acc = createVector(0,0);

  this.maxspeed = 3;

  this.prevPos = this.pos.copy();

  this.update = function() {

    this.vel.add(this.acc);

    this.vel.limit(this.maxspeed);

    this.pos.add(this.vel);

    this.acc.mult(0);

  }

  this.follow = function(vectors) {

    let x = floor(this.pos.x / scl);

    let y = floor(this.pos.y / scl);

    let index = x + y * cols;

    let force = vectors[index];

    this.applyForce(force);

  }

  this.applyForce = function(force) {

    this.acc.add(force);

  }

  this.show = function() {

    if (frameCount < 270) {

      stroke(40, 250, 250, 15);

    } else {

      stroke(247, 55, 250, 5)

    }

    strokeWeight(1);

    line(this.pos.x, this.pos.y, this.prevPos.x, this.prevPos.y);

    this.updatePrev();

  }

  this.updatePrev = function() {

    this.prevPos.x = this.pos.x;

    this.prevPos.y = this.pos.y;

  }

  this.edges = function() {

    if (this.pos.x > width) {

      this.pos.x = 0;

      this.updatePrev();

    }

    if (this.pos.x < 0) {

      this.pos.x = width;

      this.updatePrev();

    }

    if (this.pos.y > height) {

      this.pos.y = 0;

      this.updatePrev();

    }

    if (this.pos.y < 0) {

      this.pos.y = height;  

      this.updatePrev();

    }

  }

}