import toxi.geom.*;

ArrayList population;

void setup(){
  size(500,500);
  smooth();
  population = new ArrayList();
  for(int i = 0; i < 100; i++){
    Vec3D p = new Vec3D(random(0,width),random(0,height),0);
    Vec3D v = new Vec3D(2,-1,0);
    agent a = new agent(p, v, random(3,4), random(0.1,0.3));
    population.add(a);
  }
}

void draw(){
  background(0);
  for(int i = 0; i < population.size(); i++){
    agent a = (agent) population.get(i);
    a.update();
    a.render();
  }
}

Vec3D alignment(ArrayList pop, float range){
    Vec3D sum = new Vec3D();
    int count = 0;
    // loop through all the agents in pop arraylist
    for(int i = 0; i < pop.size(); i++){
        // get one agent out of the arraylist - call it a
        agent a = (agent) pop.get(i);
        // calculate distance to agent a
        float d = pos.distanceTo(a.pos);
        // is agent inside range of vis: if d < range
        if( (d < range) && (a != this) ){
          // add agent a vel to sum and add 1 to count
          sum.addSelf(a.vel); 
          count++; // count = count + 1
        }
    }
    // find the average vel: sum/count:  sum * 1/count
    if(count > 0){
      sum.scaleSelf(1/(float)count);
      // limit average vel
      sum.limit(maxForce);
    }
    // return the limited average vel
    return sum;
  }