const populationSize = 100;

​

// Length of the circular track

const trackRadius = 200;

​

// Maximum number of iterations

const maxIterations = 500;

​

// Mutation rate

const mutationRate = 0.01;

​

// Array to store the cars

let cars = [];

​

// Best car

let bestCar;

​

// Helper function to calculate the distance between two points

function calculateDistance(x1, y1, x2, y2) {

  const dx = x2 - x1;

  const dy = y2 - y1;

  return Math.sqrt(dx * dx + dy * dy);

}

​

// Car class

class Car {

  constructor() {

    this.position = createVector(trackRadius, 0);

    this.velocity = createVector(0, 0);

    this.angle = 0;

    this.fitness = 0;

    this.finished = false;

    this.crashed = false;

​

    // Array of random instructions for the car

    this.instructions = [];

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

      this.instructions.push(p5.Vector.random2D());

    }

  }

​

  // Update the car's position and check for collisions

  update() {

    if (!this.finished && !this.crashed) {

      this.position.add(this.velocity);

      this.velocity.limit(3);

      this.angle = this.velocity.heading();

​

      // Check if the car has reached the finish line

      const distance = calculateDistance(0, 0, this.position.x, this.position.y);

      if (distance < trackRadius) {

        this.finished = true;

      }

​

      // Check for collisions with the track boundary

      if (distance > trackRadius + 10 || this.position.x < 0 || this.position.y < 0) {

        this.crashed = true;

      }

    }

  }

​

  // Apply the next instruction to the car's velocity

  applyInstruction(instruction) {

    this.velocity.add(instruction);

  }

​

  // Calculate the fitness of the car

  calculateFitness() {

    const distance = calculateDistance(0, 0, this.position.x, this.position.y);

    this.fitness = map(distance, 0, trackRadius, trackRadius, 0);

    if (this.finished) {

      this.fitness *= 10;

    }

    if (this.crashed) {

      this.fitness /= 10;

    }

  }

​

  // Create a copy of the car with mutated instructions

  makeCopy() {

    const copy = new Car();

    copy.instructions = this.instructions.slice();

    for (let i = 0; i < copy.instructions.length; i++) {

      if (random() < mutationRate) {

        copy.instructions[i] = p5.Vector.random2D();

      }

    }

    return copy;

  }

}

​

function setup() {

  createCanvas(600, 600);

​

  // Create the initial population of cars

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

    cars.push(new Car());

  }

}

​

function draw() {

  background(220);

​

  // Update and draw the cars

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

    const car = cars[i];

    car.update();

    car.calculateFitness();

​

    if (!car.crashed) {

      push();

      translate(width / 2, height / 2);

      rotate(car.angle);

      fill(0, 255, 0);

      rect(trackRadius - 10, -5, 20, 10);

      pop();

    }

  }

​

  // Find the best car

  let maxFitness = 0;

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

    const car = cars[i];

    if (car.fitness > maxFitness) {

      maxFitness = car.fitness;

      bestCar = car;

    }

  }

​

  // Draw the best car in a different color

  if (bestCar) {

    push();

    translate(width / 2, height / 2);

    rotate(bestCar.angle);

    fill(255, 0, 0);

    rect(trackRadius - 10, -5, 20, 10);

    pop();

  }

​

  // Generate the next generation of cars

  const nextGeneration = [];

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

    const parent = selectParent(cars);

    const child = parent.makeCopy();

    nextGeneration.push(child);

  }

​

  cars = nextGeneration;

}

​

// Select a parent car based on fitness

function selectParent(cars) {

  let totalFitness = 0;

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

    totalFitness += cars[i].fitness;

  }

​

  let rand = random(totalFitness);

  let sum = 0;

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

    sum += cars[i].fitness;

    if (sum > rand) {

      return cars[i];

    }

  }

}

​

​