// Seung Joon Choi
// http://epicure.graffity.net : underconstruction
// epicure@hanmail.net
// 2005.09.22.

Particle[] ptcls;
int n_ptcls;
int h = 0;

void setup()
{
  size(640, 480, P3D);
  background(random(255), random(255), random(255));  
  noStroke();
  n_ptcls = 50 + (int)random(150);
  ptcls = new Particle[n_ptcls];
  if(random(1) > 0.5)
  {
    h = (int)(25 + random(220));
  }
  else
  {
    h = 0;
  }
  
  for(int i = 0; i < n_ptcls; i++)
  {
    ptcls[i] = new Particle(random(width), random(height), 5 + random(10), h);  
  }      
}

void draw()
{
  for(int i = 0; i < n_ptcls; i++)
  {
    if(i == 0)
    {
      //ptcls[i].Interact(mouseX, mouseY);
      ptcls[i].Interact(ptcls[n_ptcls-1].x, ptcls[n_ptcls-1].y);
    }
    else
    {
      ptcls[i].Interact(ptcls[i-1].x, ptcls[i-1].y); 
      for(int j = 0; j < n_ptcls; j++)
      { 
        int k = 0;
        float vx = 0;
        float vy = 0;       
        if(i != j)
        {
          float dx = ptcls[i].x - ptcls[j].x;
          float dy = ptcls[i].y - ptcls[j].y;
          float d = sqrt(dx*dx + dy*dy);
          if(d < ptcls[i].r * 2)
          {
            vx += ptcls[j].vx;
            vy += ptcls[j].vy;
            k++;
            if(d < ptcls[i].r)
            {
                ptcls[i].x += dx * 0.02;
                ptcls[i].y += dy * 0.02;
                ptcls[j].x += -dx * 0.02;
                ptcls[j].y += -dy * 0.02;
            }
          }
          if(k != 0)
          {
            ptcls[i].vx += vx / (float)k * 0.05;
            ptcls[i].vy += vy / (float)k * 0.05;
            ptcls[i].vx *= 0.99;
            ptcls[i].vy *= 0.99;
          }
        }
      }
    }
    
    ptcls[i].Render();  
  }
}