// Method to update location
 public void update() {
   // Update velocity
   vel.add(acc);
   // Limit speed
   vel.limit(maxspeed);
   loc.add(vel);
   // Reset accelertion to 0 each cycle
   acc.mult(0);
 }
    public void avoid(ArrayList obstacles) {

      // Make a vector that will be the position of the object
      // relative to the Boid rotated in the direction of boid's velocity
      PVector closestRotated = new PVector(sight + 1, sight + 1);
      float closestDistance = 99999;
      Obstacle avoid = null;

      // Let's look at each obstacle
      for (int i = 0; i < obstacles.size(); i++) {
        Obstacle o = (Obstacle) obstacles.get(i);

        float d = PVector.dist(loc, o.loc);
        PVector dir = vel.get();
        dir.normalize();
        PVector diff = PVector.sub(o.loc, loc);

        // Now we use the dot product to rotate the vector that points from boid to obstacle
        // Velocity is the new x-axis
        PVector rotated = new PVector(diff.dot(dir), diff.dot(getNormal(dir)));

        // Is the obstacle in our path?
        if (PApplet.abs(rotated.y) < (o.radius + r)) {
          // Is it the closest obstacle?
          if ((rotated.x > 0) && (rotated.x < closestRotated.x)) {
            closestRotated = rotated;
            avoid = o;
          }
        }
      }

      // Can we actually see the closest one?
      if (PApplet.abs(closestRotated.x) < sight) {

        // The desired vector should point away from the obstacle
        // The closer to the obstacle, the more it should steer
        PVector desired =
            new PVector(closestRotated.x, -closestRotated.y * sight / closestRotated.x);
        desired.normalize();
        desired.mult(closestDistance);
        desired.limit(maxspeed);
        // Rotate back to the regular coordinate system
        rotateVector(desired, vel.heading2D());

        // Draw some debugging stuff
        if (debug) {
          stroke(0);
          line(loc.x, loc.y, loc.x + desired.x * 10, loc.y + desired.y * 10);
          avoid.highlight(true);
        }

        // Apply Reynolds steering rules
        desired.sub(vel);
        desired.limit(maxforce);
        acc.add(desired);
      }
    }