// Daniel Shiffman

// http://natureofcode.com

​

// How long should each generation live

let lifetime;

let lifeCounter;

​

// Population

let population;

​

// Target position

let target;

​

// Interface

let slider;

​

function setup() {

  const canvas = createCanvas(640, 240);

​

  // Move the target if you click on the canvas

  canvas.mousePressed(function () {

    target.x = mouseX;

    target.y = mouseY;

  });

​

  // Improve performance for many small neural networks

  ml5.tf.setBackend("cpu");

​

  // The number of cycles we will allow a generation to live

  lifetime = 200;

  lifeCounter = 0;

​

  // Arbitrary starting target

  target = createVector(20, height / 2);

​

  // Create a population N Particles

  population = new Population(100);

​

  // Slider for speeding up simulation

  slider = createSlider(1, 20, 1);

  slider.position(10, height - 20);

}

​

function draw() {

  // Update the population

  for (let n = 0; n < slider.value(); n += 1) {

    if (lifeCounter < lifetime) {

      population.update();

      lifeCounter += 1;

      // Otherwise a new generation

    } else {

      lifeCounter = 0;

      // Next generation

      population.calculateFitness();

      population.reproduction();

    }

  }

​

  // Draw target

  background(255);

  fill(100, 255, 100);

  stroke(0);

  rectMode(CENTER);

  rect(target.x, target.y, 24, 24);

​

  // Show population

  population.show();

​

  // Display some info

  fill(0);

  noStroke();

  text(

    `Generation # ${population.generations}\nCycles left: ${

      lifetime - lifeCounter

    }`,

    10,

    20

  );

}

​