let lifespan = 300;

let lifeP;

let count = 0;

let target;

​

let gen = 0;

let genP;

​

function setup() {

  createCanvas(500, 500);

  p = new Population(25);

  lifeP = createP();

  genP = createP();

  target = createVector(width / 2, 200);

}

​

function draw() {

  background(0);

    p.run();

    lifeP.html(count);

    count++;

    if (count == lifespan) {

      p.evaluate();

      p.selection();

      gen++;

      count = 0;

    }

    genP.html(gen);

  ellipse(target.x, target.y, 16, 16);

​

}

​

function DNA(genes) {

  if (genes) {

    this.genes = genes;

  } else {

    this.genes = [];

  }

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

    this.genes[i] = p5.Vector.random2D();

    this.genes[i].setMag(0.1);

  }

​

  this.crossover = function(partner) {

    let newgenes = [];

    let mid = floor(random(this.genes.length));

    for (let i = 0; i < this.genes.length; i++) {

      if (i > mid) {

        newgenes[i] = this.genes[i];

      } else {

        newgenes[i] = partner.genes[i];

      }

    }

    return new DNA(newgenes);

  }

}

​

function Population(size, dna) {

  this.rockets = [];

  this.popsize = size;

  this.matingpool = [];

​

  for (let i = 0; i < this.popsize; i++) {

    this.rockets[i] = new Rocket();

  }

​

  this.evaluate = function() {

    let maxfit = 0;

    for (let i = 0; i < this.popsize; i++) {

      this.rockets[i].calcFitness();

      if (this.rockets[i].fitness > maxfit) {

        maxfit = this.rockets[i].fitness;

      }

    }

    for (let i = 0; i < this.popsize; i++) {

      this.rockets[i].fitness /= maxfit;

    }

    this.matingpool = [];

​

    for (let i = 0; i < this.popsize; i++) {

      let n = this.rockets[i].fitness * 100;

      for (let j = 0; j < n; j++) {

        this.matingpool.push(this.rockets[i]);

      }

    }

  }

​

  this.selection = function() {

    let newRockets = [];

    for (let i = 0; i < this.rockets.length; i++) {

      let parentA = random(this.matingpool).dna;

      let parentB = random(this.matingpool).dna;

      let child = parentA.crossover(parentB);

      newRockets[i] = new Rocket(child);

    }

​

    this.rockets = newRockets;

  }

​

  this.run = function() {

    for (let i = 0; i < this.popsize; i++) {

      this.rockets[i].update();

      this.rockets[i].show();

    }

  }

}

​

function Rocket(dna) {

  this.pos = createVector(width / 2, height);

  //this.vel = p5.Vector.random2D();

  this.vel = createVector();

  this.acc = createVector();

​

  this.completed = false;

​

  if (dna) {

    this.dna = dna;

  } else {

    this.dna = new DNA();

  }

  this.fitness = 0;

​

  this.applyForce = function(force) {

    this.acc.add(force);

  }

​

  this.update = function() {

    let d = dist(this.pos.x, this.pos.y, target.x, target.y);

​

    if (d < 10) {

      this.completed = true;

      this.pos = target.copy();

    }

​

    this.applyForce(this.dna.genes[count]);

    if (!this.completed) {

      this.vel.add(this.acc);

      this.pos.add(this.vel);

      this.acc.mult(0);

    }

  }

​

  this.show = function() {

    push();

    fill(255, 100);

    noStroke();

    translate(this.pos.x, this.pos.y);

    rotate(this.vel.heading());

    rectMode(CENTER);

    rect(0, 0, 50, 10);

    pop();

  }

​

  this.calcFitness = function() {

    let d = dist(this.pos.x, this.pos.y, target.x, target.y);

    this.fitness = map(d, 0, width, width, 0);

​

    if (this.completed) {

      this.fitness *= 10;

    }

  }

}