private IList <LocationWrapper> GetNeighbours(Location current)
{
IList <LocationWrapper> neighbours = new List <LocationWrapper> ();
// north of current
LocationWrapper north = new LocationWrapper(new Location(current.X - 1, current.Y));
LocationWrapper south = new LocationWrapper(new Location(current.X + 1, current.Y));
LocationWrapper west = new LocationWrapper(new Location(current.X, current.Y - 1));
LocationWrapper east = new LocationWrapper(new Location(current.X, current.Y + 1));
if (north.Location.X >= 0)
{
neighbours.Add(north);
}
if (south.Location.X < this.map.Tiles.GetLength(0))
{
neighbours.Add(south);
}
if (east.Location.Y < this.map.Tiles.GetLength(1))
{
neighbours.Add(east);
}
if (west.Location.Y >= 0)
{
neighbours.Add(west);
}
return(checkNeighbours(neighbours));
}
private bool contains(IList <LocationWrapper> closedList, LocationWrapper location)
{
foreach (var l in closedList)
{
if (l.Location.X == location.Location.X && l.Location.Y == location.Location.Y)
{
return(true);
}
}
return(false);
}
private IList <Location> Backtrack(LocationWrapper current)
{
IList <Location> path = new List <Location>();
path.Add(current.Location);
while (current.Parent != null)
{
path.Add(current.Parent.Location);
current = current.Parent;
}
return(path.Reverse().ToList());
}
public IList <Location> A_star(Location Start, Location finish)
{
IList <LocationWrapper> openlist = new List <LocationWrapper>();
IList <LocationWrapper> closedList = new List <LocationWrapper>();
var StartWrapper = new LocationWrapper(Start);
StartWrapper.Parent = null;
openlist.Add(StartWrapper);
while (openlist.Count > 0)
{
var current = GetMin(openlist);
openlist.Remove(current);
if (current.Location.X == finish.X && current.Location.Y == finish.Y)
{
return(Backtrack(current));
}
var Neighbours = GetNeighbours(current.Location);
closedList.Add(current);
foreach (var location in Neighbours)
{
if (!contains(closedList, location))
{
var new_G = current.G_score + 1;
if (openlist.Contains(location))
{
if (new_G < location.G_score)
{
location.Parent = current;
location.G_score = new_G;
}
}
else
{
if (location.Parent == null)
{
location.Parent = current;
}
location.G_score = new_G;
openlist.Add(location);
}
location.H_score = CalculateDistance(location.Location, finish);
if (this.map.Tiles[location.Location.X, location.Location.Y].TileType == TileType.Enemy)
{
location.E_score = 150;
}
}
}
}
return(null);
}
