class lattice
{
  mass nodes[];
  int amount=0;
  float minDistance=50;
  float tension=g_tension;
  lattice(int a)
  {
    amount=a;
    nodes=new mass[amount];
    for(int nodeIndex=0;nodeIndex<amount;nodeIndex++)
    {
      position p=new position(width/2,height/2);
      float ang=float(nodeIndex)/float(amount)*360;
      float dist=minDistance;
      nodes[nodeIndex]=new mass(p.displace(ang,50));
    }
  }  
  void update()
  {
    for(int i=0;i<nodes.length;i++)
    {
      nodes[i].update();
    }
    doSprings();
  }
  void drawLattice()
  {
    noFill();
    float t=tension*200;
    for(int i=0;i<nodes.length;i++)
    {
      for(int s=i;s<nodes.length;s++)
      {
        float a=255-(dist(nodes[i].p,nodes[s].p)/150*255);
        if(a>15)
        {
          stroke(25,220,80+t,a);
          line(nodes[i].x(),nodes[i].y(),nodes[s].x(),nodes[s].y());  
        }
      }
//      noStroke();
//      fill(205);
      float vel=nodes[i].velocity.m;
      stroke(25+vel/5*100,220,80+t);        
      ellipse(nodes[i].x(),nodes[i].y(),5+constrain((vel*1.5),0,8),5+constrain((vel*1.5),0,8));
    }
  }
  void doSprings()
  {
    for(int i=0;i<amount;i++)
    {
      for(int s=i+1;s<amount;s++)
      {
        float distance=dist(nodes[i].p,nodes[s].p);      
        if(s!=i)
        {
          if(true)
          {
            vector f=getSpringForce(nodes[i].p,nodes[s].p,minDistance,tension);
//            vector f=new vector();
            
            float forceMag=f.m/2;
            float angle=f.a;
            float angleOp=f.a+180;
            
            nodes[i].velocity=nodes[i].velocity.add(f.a,forceMag);
            nodes[s].velocity=nodes[s].velocity.add(f.a,forceMag*-1);
//            nodes[i].p=nodes[i].p.displace(f.a,forceMag);       
//            nodes[s].p=nodes[s].p.displace(f.a,forceMag*-1);
          }
        } 
     
      }
    }  
  }
  void addNode()
  {
    amount++;
    mass tempNodes[]=new mass[amount];
    for(int i=0;i<nodes.length;i++)
    {
      tempNodes[i]=nodes[i];
    }
    tempNodes[amount-1]=new mass(new position(mouseX+random(-1,1),mouseY+random(-1,1)));
    nodes=tempNodes;
  }
}