//-----------------------------------------------------------------------------------
// which directions are allowed now?
//-----------------------------------------------------------------------------------
protected List <Direction> allowedDirections()
{
// if two or more potential choices are an equal distance from the target,
// the decision between them is made in the order of up > left > down (> right)
List <Direction> directions = new List <Direction>();
Direction direction = walker.direction();
WaypointNode node = walker.getCurrentNode();
if (node.getFront() != null && !direction.isOpposite(Direction.Front))
{
directions.Add(Direction.Front);
}
if (node.getLeft() != null && !direction.isOpposite(Direction.Left))
{
directions.Add(Direction.Left);
}
if (node.getBack() != null && !direction.isOpposite(Direction.Back))
{
directions.Add(Direction.Back);
}
if (node.getRight() != null && !direction.isOpposite(Direction.Right))
{
directions.Add(Direction.Right);
}
return(directions);
}
protected virtual Direction directionFrightened()
{
// ghosts use a pseudo-random number generator (PRNG)
// to pick a way to turn at each intersection when frightened
System.Random rnd = new System.Random();
Direction direction = (Direction)rnd.Next(4);
if (validDirection(direction))
{
return(direction);
}
// if a wall blocks the chosen direction,
// the virus then attempts the remaining directions in this order:
// up, left, down, and right, until a passable direction is found
WaypointNode node = walker.getCurrentNode();
if (node.getFront() != null)
{
return(Direction.Front);
}
if (node.getLeft() != null)
{
return(Direction.Left);
}
if (node.getBack() != null)
{
return(Direction.Back);
}
if (node.getRight() != null)
{
return(Direction.Right);
}
return(Direction.None);
}
//-----------------------------------------------------------------------------------
// find out if we the virus can move in the specified direction
//-----------------------------------------------------------------------------------
protected bool validDirection(Direction direction)
{
WaypointNode node = walker.getCurrentNode();
if (direction == Direction.Front)
{
return(node.getFront() != null);
}
if (direction == Direction.Back)
{
return(node.getBack() != null);
}
if (direction == Direction.Left)
{
return(node.getLeft() != null);
}
if (direction == Direction.Right)
{
return(node.getRight() != null);
}
return(false);
}