constructor(x, y, col, r) {

    this.position = createVector(x, y);

    this.velocity = createVector(0, 0);

    this.acceleration = createVector(0, 0);

    this.r = r;

    this.maxspeed = 4;

    this.maxforce = 0.2;

    this.color = col;

    this.wanderTheta = 0;

    this.currentPath = [];

    this.paths = [this.currentPath];

  }

​

  wander() {

    // creating projected wandering point

    let wanderPoint = this.velocity.copy();

    wanderPoint.setMag(100);

    wanderPoint.add(this.position);

    //displaying wandering point

    // fill(255, 0, 0);

    // noStroke();

    // circle(wanderPoint.x, wanderPoint.y, 8);

​

    //creating a circular path around my wandering point

    let wanderRadius = 20;

    // noFill();

    // stroke(0);

    // circle(wanderPoint.x, wanderPoint.y, wanderRadius * 2);

    // line(this.position.x, this.position.y, wanderPoint.x, wanderPoint.y);

​

    //the angle is relevant to the direction the vehicle's current velocity

    let theta = this.wanderTheta + this.velocity.heading();

​

    //finding the point on the circumference of the circular path, remember polar to cartesian coordinates

    let x = wanderRadius * cos(theta);

    let y = wanderRadius * sin(theta);

    wanderPoint.add(x, y);

    //displaying new wandering point on circular path and line to it

    // fill(0, 255, 0);

    // noStroke();

    // circle(wanderPoint.x, wanderPoint.y, 10);

    // stroke(0);

    // line(this.position.x, this.position.y, wanderPoint.x, wanderPoint.y);

​

    //the steering force here is equivalent to the desired velocity = target-position

    let steer = wanderPoint.sub(this.position);

    steer.setMag(this.maxForce);

    this.applyForce(steer);

​

    //random displacement along the circumference

    let displaceRange = 0.3;

    this.wanderTheta += random(-displaceRange, displaceRange);

  }

​

  //The pursue method is figuring out the predicted future position and calling the seek() method

  pursue(vehicle) {

    let target = vehicle.position.copy();

    let prediction = vehicle.velocity.copy();

    prediction.mult(10); //looking 10 steps ahead

    target.add(prediction);

    // fill(0, 255, 0);

    // circle(target.x, target.y, 10); //to visualise the prediction

    return this.seek(target);

  }

​

  evade(vehicle) {

    let pursuit = this.pursue(vehicle);

    pursuit.mult(-1);

    return pursuit;

  }

​

  arrive(target) {

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

​

    let distance = desired.mag();

    let r = 100; //our raduis for threshold

    if (distance < r) {

      let m = map(distance, 0, r, 0, this.maxspeed);

      desired.setMag(m);

    } else {

      desired.setMag(this.maxspeed);

    }

​

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

    steer.limit(this.maxforce);

    return steer;

  }

​

  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;

  }

​

  flee(target) {

    return this.seek(target).mult(-1);

  }

​

  applyForce(force) {

    this.acceleration.add(force);

  }

​

  update() {

    this.velocity.add(this.acceleration);

    this.velocity.limit(this.maxspeed);

    this.position.add(this.velocity);

    this.acceleration.set(0,0);

    this.currentPath.push(this.position.copy());

  }

​

  show() {

    let angle = this.velocity.heading();

    fill(this.color);

    stroke(0);

    push();

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

    rotate(angle);

    triangle(-this.r, -this.r / 2, -this.r, this.r / 2, this.r, 0);

    pop();

    push();

    for (let path of this.paths) {

      beginShape();

      noFill();

      stroke(255);

      for (let v of path) {

        vertex(v.x, v.y);

      }

      endShape();

    }

    pop();

  }

​

  edges() {

    let cross_edge = false;

    if (this.position.x > width + this.r) {

      this.position.x = -this.r;

      cross_edge = true;

    } else if (this.position.x < -this.r) {

      this.position.x = width + this.r;

      cross_edge = true;

    }

    if (this.position.y > height + this.r) {

      this.position.y = -this.r;

      cross_edge = true;

    } else if (this.position.y < -this.r) {

      this.position.y = height + this.r;

      cross_edge = true;

    }

    if (cross_edge == true) {

      this.currentPath = [];

      this.paths.push(this.currentPath);

    }

  }

}

​