Vigo

Vigo::3D, or Vigo for short (pronounced: veeh-goh) is a framework for simulating and visualizing of three-dimensional scenes. Vigo is suited for creating dynamical systems of interacting agents, in which the agents move in a three-dimensional space, and perceive (“see”) their neighbours around them.

bool Act()
{
  switch(ActPhase())
  {
    case 0: // move
      MoveBy(Vector(Point::Random(Point::_0,MAX_STEP_SIZE)));
      break;
    case 1: // think
      // only look for neighbours of your kind
      Nbr(GrpId(),VISION_RADIUS,m_nearMe,MAX_SHOWN_NBR,true);
      // determine shade
      uint   ns = m_nearMe.size();
      double dn = ((double)ns+1/*myself*/)/MAX_SHOWN_NBR;
      dn *= NUM_SHADES;
      uint nn = min((uint)dn,NUM_SHADES-1);
      // the more neighbours, the darker
      SetAppearance(Scale()[NUM_SHADES-1-nn]);
      break;
  }
}