private int DistanceSquared(Tile a, Tile b)
{
int deltaX = b.MapLocation.X - a.MapLocation.X;
int deltay = b.MapLocation.Y - a.MapLocation.Y;
return (deltaX * deltaX) + (deltay * deltay);
}
public Path(Tile[,] tiles, Tile start, Tile end)
{
Entries = new List<Tile>(tiles.GetLength(0) + tiles.GetLength(1));
Length = new Point(tiles.GetLength(0), tiles.GetLength(1));
for (int y = 0; y < Length.Y; y++)
{
for (int x = 0; x < Length.X; x++)
{
Entries.Add(tiles[x, y]);
}
}
Start = start;
End = end;
}
public void AStar(Tile start, Tile end)
{
List<Tile> open = new List<Tile>();
open.Add(start);
List<Tile> closed = new List<Tile>();
Tile l = null;
while (l != end && open.Count != 0 && end.Parent == null)
{
l = FindBestNode(open);
if (l.Equals(end))
continue;
else
{
open.Remove(l);
closed.Add(l);
l.Region = DisplayRegion.Closed;
foreach (Tile adj in l.AdjacencyList)
{
if (adj.Type == TileType.NotPassable || closed.Contains(adj))
continue;
if (!open.Contains(adj))
{
AddToOpenList(open, adj, l, end);
adj.Parent = l;
}
else
{
int newDistance = l.DistanceFromStart + DistanceSquared(l, adj);
if (newDistance < adj.DistanceFromStart)
{
adj.Parent = l;
adj.DistanceFromStart = newDistance;
}
}
}
}
}
if (end.Parent != null)
GeneratePath(start, end);
else
throw new Exception("Check to make sure that your path is a valid path (monsters can travel along the path from start to finish)");
start.Region = DisplayRegion.Start;
}
public void AddToAdjacencyList(Tile t)
{
if (t == null) return;
if (AdjacencyList == null)
AdjacencyList = new List<Tile>();
AdjacencyList.Add(t);
}
private void AddToOpenList(List<Tile> open, Tile adj, Tile l, Tile end)
{
adj.DistanceFromStart = l.DistanceFromStart + DistanceSquared(l, adj);
adj.DistanceToEnd = DistanceSquared(adj, end);
open.Add(adj);
}
private void GeneratePath(Tile start, Tile end)
{
path = new List<Tile>();
Tile p = end.Parent;
while (p != start)
{
path.Insert(0, p);
p.Region = DisplayRegion.InPath;
p = p.Parent;
}
}