let s;

​

const maxAgents = 100;

const minAgents = 10;

let agents = [];

​

let freeSpots;

​

let pallette = [

  // Peachy

  // "#BA7BA1",

  // "#C28CAE",

  // "#D0ABA0",

  // "#DEC4A1",

  // "#EDCF8E",

  // Forest  

  // "#395e66", 

  // "#387d7a", 

  // "#32936f", 

  // "#26a96c", 

  // "#2bc016",

  // Sunrise

  "#F9C80E", 

  "#EF5D60", 

  "#EC4067", 

  "#A01A7D", 

  "#5E239D",

];

​

function setup() {

  createCanvas(900, 900);

  randomSeed(1);

  s = width/cells;

  setFreeSpots();

  for(let i = 0; i < maxAgents; i ++) {

    newAgent();

  }

  noStroke();

  background(255);

  // noLoop();

}

​

function draw() {

  if(numFreeSpots() || agents.length) {

    for(let a = agents.length - 1; a >= 0; a --) {

      agents[a].draw();

      if(!agents[a].update()) {

        agents.splice(a, 1);

      }

    }

    if(agents.length < minAgents) {

      let n = min(minAgents - agents.length, numFreeSpots());

      for(let i = 0; i < n; i ++) {

        newAgent(); 

      }

    }

  }

}

​

class Agent {

  constructor(x, y) {

    this.p = createVector(x, y);

    this.c = randomColour();

    this.d = floor(random(4));

    this.draw();

    this.s = createVector(x, y);

  }

  update() {

    let dirs = [this.d, left(this.d), right(this.d)];

    let next;

    for(let d of dirs) {

      next = move(this.p, d);

      if(next && freeSpots[next]) {

        this.p = next;

        this.d = d;

        delete freeSpots[next];

        return true;

      }

    }

    if(!(this.p.x === this.s.x && this.p.y === this.s.y)) {

      this.p.x = this.s.x;

      this.p.y = this.s.y;

      return this.update();

    }

    return false;

  }

  draw() {

    fill(this.c);

    square(this.p.x * s, this.p.y * s, s);

  }

}

​

function newAgent() {

  let keys = Object.keys(freeSpots);

  let k = keys[floor(random(keys.length))];

  let p = freeSpots[k];

  agents.push(new Agent(p.x, p.y));

  delete freeSpots[k];

}

​

function numFreeSpots() {

  return Object.keys(freeSpots).length;

}

​

function setFreeSpots() {

  freeSpots = {};

  for(let i = 0; i < cells; i ++) {

    for(let j = 0; j < cells; j ++) {

      let v = createVector(i, j);

      freeSpots[v] = v;

    }

  }

}

​

function move(pos, dir) {

  let a = dir * HALF_PI;

  let n = createVector(pos.x + round(cos(a)), pos.y + round(sin(a)));

  if(n.x < 0 || n.x >= cells || n.y < 0 || n.y >= cells) {

    return null;

  }

  return n;

}

​

function left(dir) {

  return (dir - 1) % 4;

}

​

function right(dir) {

  return (dir + 1) % 4;

}

​

function randomColour() {

  return pallette[floor(random(pallette.length))];

}