/// <summary>
/// This method steps through one unit of time in the pigWorld. It loops over
/// every LifeForm in the pigWorld and calls the DoSomething() method on each
/// LifeForm once. You can use the Step method while the pigWorld is stopped to
/// see how the pigWorld changes after one unit of time.
/// To make multiple steps, this method can be called repeatedly,
/// e.g. by the periodic tick of a timer.
/// </summary>
public virtual void Step()
{
now += 1;
// Make any sounds in the air dampen over time.
if (now % 3 == 0)
{
for (int row = 0; row < numOfRows; row++)
{
for (int column = 0; column < numOfColumns; column++)
{
cells[row, column].Air.DecrementSoundLevel();
}
}
}
// Update each Thing in the pigWorld, for this moment in time.
// Items can be added to, and removed from, the list of Things as each LifeForm gets
// its slice of time. E.g. pigs can be born, or eaten by a wolf.
// To make sure that only existing Things get their time-slice on the current Step,
// we make a copy of the list first.
List <Thing> localListOfThings = new List <Thing>(Things);
for (int i = 0; i < localListOfThings.Count; i++)
{
// The Things update themselves, so we can't use "foreach" here.
Thing thing = localListOfThings[i];
if (thing is LifeForm)
{
LifeForm lifeForm = (LifeForm)thing;
if (lifeForm.Exists())
{
lifeForm.HandleTime();
}
}
else
{
// Refresh the display of NonlivingThings periodically.
if (now % 6 == 0)
{
Cell cell = thing.Cell;
if (cell != null)
{
cell.Pulse();
}
}
}
}
}
