public void start(Board board, Agent agent, Territory start, Territory finish)
{
// must create a path from start territory to finish territory
TerritoryList territories = board.Territories;
OpenSet.Add(new StarTile(start.Name, start));
Dictionary<string, int> sldMap = CalculateSLD(finish.Name);
// loop through A* steps until goal is reached
while (!IsGoalFound)
{
StarTile current = GetMinFValue();
// there are no more members of the OpenSet to examine
if(current == null)
{
break;
}
// current territory is finish territory
if(current.Id == finish.Name)
{
// do something?
}
List<StarTile> frontier = GetFrontier(current);
// loop through frontier and calculate heuristic for current territory
foreach(StarTile t in frontier)
{
// associate frontier territory to parent tile
t.Parent = current; // is this really necessary since we do it below?
// enemy territories are considered empty tiles, available to be conquered
if(t.Territory.Owner != current.Territory.Owner)
{
CalculateHeuristic(t, start, finish);
t.Parent = current;
}
// goal territory is reached
else if(t.Territory.Name == finish.Name)
{
t.Parent = current;
IsGoalFound = true;
Path = ConstructPath(t);
}
// self owned territory, seen as obstacle because it is already
else if(t.Territory.Owner == current.Territory.Owner)
{
// do not need to calculate anything, just skip
}
}
}
}
public BfsTile(string id, Territory territory)
{
Id = id;
Territory = territory;
Parent = null;
Distance = 0;
}
public StarTile(string id, Territory territory)
{
Id = id;
Territory = territory;
Parent = null;
HValue = 0;
GValue = 0;
FValue = 0;
}
/// <summary>
/// Adds a new node to the graph.
/// </summary>
/// <param name="key">The key value of the node to add.</param>
/// <param name="data">The data of the node to add.</param>
/// <returns>A reference to the Territory that was created and added to the graph.</returns>
/// <remarks>If there already exists a node in the graph with the same <b>key</b> value then an
/// <b>ArgumentException</b> exception will be thrown.</remarks>
public virtual Territory AddNode(Territory t)
{
// Make sure the key is unique
if (!territories.ContainsKey(t.Name))
{
territories.Add(t);
return t;
}
else
throw new ArgumentException("There already exists a node in the graph with name " + t.Name);
}
private void CalculateHeuristic(StarTile tile, Territory start, Territory finish, Dictionary<string,int> sldMap)
{
if (tile.Parent != null)
{
tile.GValue = tile.Parent.GValue + 1;
tile.HValue = sldMap[tile.Id];
tile.FValue = tile.GValue + tile.HValue;
}
}
/// <summary>
/// Removes a Territory from the NodeList.
/// </summary>
public virtual Territory Remove(Territory t)
{
Territory removed = (Territory) data[t.Name];
data.Remove(t.Name);
return removed;
}
/// <summary>
/// Adds a new Territory to the NodeList.
/// </summary>
public virtual void Add(Territory t)
{
data.Add(t.Name, t);
}
/// <summary>
/// Determines if a node exists within the graph.
/// </summary>
/// <param name="t">The node to check for in the graph.</param>
/// <returns><b>True</b> if the node <b>n</b> exists in the graph, <b>False</b> otherwise.</returns>
public virtual bool Contains(Territory t)
{
return ContainsTerritory(t.Name);
}