// Flocking Particle
// - hacky implementation so far, but that's mainly to get it to work with my Physics class
// by dickering with the general rule speeds you'll get the sort of behaviour that will look cool

class Boid extends Particle{
  float centering = 0.01;
  float avoidance = 0.05;
  float goalSpeed = 0.08;
  int id;
  BoidFlock p;
  // Constructor
  Boid(float x, float y, BoidFlock p){
    super(x, y, p);
    this.p = p;
  }
  // Keep the boid moving towards the center of the group
  void group(){
    // center measurements
    float vx = p.center.x-x;
    float vy = p.center.y-y;
    float invLen = Line.invSqrt(vx * vx + vy * vy);
    float dx = vx * invLen;
    float dy = vy * invLen;
    addVelocity(dx*centering, dy*centering);
  }
  // Avoid other boids
  void avoid(){
    Point move = new Point(0, 0);
    for(int i = 0; i < p.p.size(); i++){
      if(i == id) continue;
      Boid temp = (Boid)p.p.get(i);
      float vx = x - temp.x;
      float vy = y - temp.y;
      float invLen = Line.invSqrt(vx * vx + vy * vy);
      if(invLen > avoidance){
        float dx = vx * invLen;
        float dy = vy * invLen;
        addVelocity(dx*avoidance, dy*avoidance);
      }
    }
  }
  // Fly toward a given goal
  void goal(float tx, float ty){
    // goal measurements
    float vx = tx-x;
    float vy = ty-y;
    float invLen = Line.invSqrt(vx * vx + vy * vy);
    float dx = vx * invLen;
    float dy = vy * invLen;
    addVelocity(dx*goalSpeed, dy*goalSpeed);
  }
}