const G = 0.5; // Gravitational constant

​

// Array to store the planets

let planets = [];

​

function setup() {

  createCanvas(windowWidth, windowHeight);

​

  // Create some planets

  planets.push(new Planet(width / 2, height / 2, 1000, createVector(0, 0))); // Sun

  planets.push(new Planet(width / 2 + 200, height / 2, 20, createVector(0, -4))); // Planet 1

  planets.push(new Planet(width / 2 + 300, height / 2, 30, createVector(0, -5))); // Planet 2

}

​

function draw() {

  background(0);

​

  // Apply gravitational forces between planets and the sun

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

    for (let j = 0; j < planets.length; j++) {

      if (i !== j) {

        let force = calculateGravitationalForce(planets[i], planets[j]);

        planets[i].applyForce(force);

      }

    }

​

    let sunForce = calculateGravitationalForce(planets[i], planets[0]); // Attract to the sun

    planets[i].applyForce(sunForce);

  }

​

  // Update and display planets

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

    planets[i].update();

    planets[i].display();

​

    // Check for collisions with other planets

    for (let j = i + 1; j < planets.length; j++) {

      if (planets[i].collidesWith(planets[j])) {

        // Create an explosion at the collision position

        let explosion = new Explosion(planets[i].position.x, planets[i].position.y, 50);

        explosion.start();

        // Remove the collided planets

        planets.splice(j, 1);

        planets.splice(i, 1);

        break;

      }

    }

  }

}

​

function calculateGravitationalForce(planetA, planetB) {

  let distance = p5.Vector.dist(planetA.position, planetB.position);

  distance = constrain(distance, 5, 25); // Constrain the distance to avoid extremely high forces

​

  let magnitude = (G * planetA.mass * planetB.mass) / (distance * distance);

  let direction = p5.Vector.sub(planetB.position, planetA.position);

  direction.normalize();

  direction.mult(magnitude);

​

  return direction;

}

​

class Planet {

  constructor(x, y, mass, velocity) {

    this.position = createVector(x, y);

    this.velocity = velocity;

    this.acceleration = createVector(0, 0);

    this.mass = mass;

    this.radius = mass / 10;

  }

​

  applyForce(force) {

    let f = p5.Vector.div(force, this.mass);

    this.acceleration.add(f);

  }

​

  update() {

    this.velocity.add(this.acceleration);

    this.position.add(this.velocity);

    this.acceleration.mult(0);

  }

​

  display() {

    fill(255);

    ellipse(this.position.x, this.position.y, this.radius * 2, this.radius * 2);

  }

​

  collidesWith(other) {

    let distance = p5.Vector.dist(this.position, other.position);

    return distance < (this.radius + other.radius);

  }

}

​

​

class Explosion {

  constructor(x, y, size) {

    this.position = createVector(x, y);

    this.size = size;

    this.particles = [];

  }

​

  start() {

    for (let i = 0; i < 100; i++) {

      let angle = random(TWO_PI);

      let magnitude = random(2, 8);

      let velocity = p5.Vector.fromAngle(angle);

      velocity.mult(magnitude);

      let particle = new Particle(this.position.x, this.position.y, velocity);

      this.particles.push(particle);

    }

  }

​

  update() {

    for (let i = this.particles.length - 1; i >= 0; i--) {

      this.particles[i].update();

      if (this.particles[i].finished()) {

        this.particles.splice(i, 1);

      }

    }

  }

​

  display() {

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

      this.particles[i].display();

    }

  }

}

​

class Particle {

  constructor(x, y, velocity) {

    this.position = createVector(x, y);

    this.velocity = velocity;

    this.acceleration = createVector(0, 0.1);

    this.lifespan = 255;

  }

​

  update() {

    this.velocity.add(this.acceleration);

    this.position.add(this.velocity);

    this.lifespan -= 5;

  }

​

  display() {

    noStroke();

    fill(255, this.lifespan);

    ellipse(this.position.x, this.position.y, 8, 8);

  }

​

  finished() {

    return this.lifespan < 0;

  }

}

​