class ParticleSystem {
  ArrayList particles;
  Vector3D origin;
  float theta;

  ParticleSystem(int num) {
    particles = new ArrayList();


    for(int i = 0; i < num; i++) {
      origin = new Vector3D(cos(i)*90.0, sin(i)*90.0);
      particles.add(new Particle(origin, new Vector3D(random(-4,4),random(-4,4)), new Vector3D(0,0),1));
    }
  }


  void run() {
    for(int i = 0; i < 36; i++) {
      origin = new Vector3D(cos(i)*40.0, sin(i)*40.0);
      particles.add(new Particle(origin, new Vector3D(random(-2,2),random(-2,2)), new Vector3D(0,0),1));
    }
    for ( int i = particles.size()-1; i >= 0; i--) {

      Particle p = (Particle) particles.get(i);
      p.run();
      if(p.dead()) {

        particles.remove(i);

      }
    }
  }

  void addParticle() {
    particles.add(new Particle(origin, new Vector3D(random(-2,2),random(-2,2)), new Vector3D(0,0),1));
  }

  void addParticle(Particle p) {
    particles.add(p);
  }

  boolean dead() {
    if(particles.isEmpty()) {
      return true;
    } 
    else {
      return false;
    }
  }
}