Evil Boid

let boids = [];

let evilBoid;

​

function setup() {

  createCanvas(800, 600);

  // Initialize boids

  for (let i = 0; i < 50; i++) {

    boids.push(new Boid(random(width), random(height)));

  }

  // Initialize evil boid

  evilBoid = new EvilBoid(width / 2, height / 2);

}

​

function draw() {

  background(30);

  // Update and show boids

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

    boids[i].flock(boids);

    boids[i].update();

    boids[i].show();

    // Check if eaten by evil boid

    if (evilBoid.eat(boids[i])) {

      boids.splice(i, 1); // Remove eaten boid

    }

  }

  // Update and show evil boid

  evilBoid.chase(boids);

  evilBoid.update();

  evilBoid.show();

}

​

// Boid class

class Boid {

  constructor(x, y) {

    this.position = createVector(x, y);

    this.velocity = p5.Vector.random2D();

    this.velocity.setMag(random(2, 4));

    this.acceleration = createVector();

    this.maxForce = 0.2;

    this.maxSpeed = 4;

  }

​

  flock(boids) {

    let separation = this.separate(boids).mult(1.5);

    let alignment = this.align(boids).mult(1.0);

    let cohesion = this.cohere(boids).mult(1.0);

​

    this.acceleration.add(separation);

    this.acceleration.add(alignment);

    this.acceleration.add(cohesion);

  }

​

  separate(boids) {

    let desiredSeparation = 25;

    let steer = createVector();

    let count = 0;

​

    for (let other of boids) {

      let d = dist(this.position.x, this.position.y, other.position.x, other.position.y);

      if (d > 0 && d < desiredSeparation) {

        let diff = p5.Vector.sub(this.position, other.position);

        diff.normalize();

        diff.div(d); // Weight by distance

        steer.add(diff);

        count++;

      }

    }

​

    if (count > 0) {

      steer.div(count);

    }

​

    if (steer.mag() > 0) {

      steer.setMag(this.maxSpeed);

      steer.sub(this.velocity);

      steer.limit(this.maxForce);

    }

    return steer;

  }

​

  align(boids) {

    let neighborDist = 50;

    let sum = createVector();

    let count = 0;

​

    for (let other of boids) {

      let d = dist(this.position.x, this.position.y, other.position.x, other.position.y);

      if (d > 0 && d < neighborDist) {

        sum.add(other.velocity);

        count++;

      }

    }

​

    if (count > 0) {

      sum.div(count);

      sum.setMag(this.maxSpeed);

      let steer = p5.Vector.sub(sum, this.velocity);

      steer.limit(this.maxForce);

      return steer;

    }

    return createVector();

  }

​

  cohere(boids) {

    let neighborDist = 50;

    let sum = createVector();

    let count = 0;

​

    for (let other of boids) {

      let d = dist(this.position.x, this.position.y, other.position.x, other.position.y);

      if (d > 0 && d < neighborDist) {

        sum.add(other.position);

        count++;

      }

    }

​

    if (count > 0) {

      sum.div(count);

      return this.seek(sum);

    }

    return createVector();

  }

​

  seek(target) {

    let desired = p5.Vector.sub(target, this.position);

    desired.setMag(this.maxSpeed);

    let steer = p5.Vector.sub(desired, this.velocity);

    steer.limit(this.maxForce);

    return steer;

  }

​

  update() {

    this.position.add(this.velocity);

    this.velocity.add(this.acceleration);

    this.velocity.limit(this.maxSpeed);

    this.acceleration.mult(0);

​

    // Wrap around edges

    if (this.position.x > width) this.position.x = 0;

    if (this.position.x < 0) this.position.x = width;

    if (this.position.y > height) this.position.y = 0;

    if (this.position.y < 0) this.position.y = height;

  }

​

  show() {

    strokeWeight(8);

    stroke(255);

    point(this.position.x, this.position.y);

  }

}

​

// EvilBoid class

class EvilBoid {

  constructor(x, y) {

    this.position = createVector(x, y);

    this.velocity = createVector();

    this.acceleration = createVector();

    this.maxSpeed = 5;

    this.maxForce = 0.3;

  }

​

  chase(boids) {

    if (boids.length === 0) return;

​

    let closest = null;

    let closestDist = Infinity;

​

    for (let boid of boids) {

      let d = dist(this.position.x, this.position.y, boid.position.x, boid.position.y);

      if (d < closestDist) {

        closestDist = d;

        closest = boid;

      }

    }

​

    if (closest) {

      this.acceleration = this.seek(closest.position);

    }

  }

​

  seek(target) {

    let desired = p5.Vector.sub(target, this.position);

    desired.setMag(this.maxSpeed);

    let steer = p5.Vector.sub(desired, this.velocity);

    steer.limit(this.maxForce);

    return steer;

  }

​

  eat(boid) {

    let d = dist(this.position.x, this.position.y, boid.position.x, boid.position.y);

    return d < 8; // Eats if within radius

  }

​

  update() {

    this.velocity.add(this.acceleration);

    this.velocity.limit(this.maxSpeed);

    this.position.add(this.velocity);

    this.acceleration.mult(0);

  }

​

  show() {

    strokeWeight(10);

    stroke(255, 0, 0);

    point(this.position.x, this.position.y);

  }

}

​