public Fringe(HeuristicFunc heuristic)
{
Heuristic = heuristic;
}
private Node GetNode(Tile t, Node parent, IDictionary <Tile, Node> nodes, CostFunc getCost, HeuristicFunc getH)
{
Node newNode = new Node(parent, t, getCost(t, parent?.Value), getH(t));
Node existingNode;
if (nodes.TryGetValue(t, out existingNode) && existingNode.F <= newNode.F)
{
return(existingNode);
}
nodes[t] = newNode;
return(newNode);
}
/// <summary>Dijkstra pathfinder with heuristic</summary>
/// <param name="start">Starting tile</param>
/// <param name="getCost">Cost function for the tile, also tells pathfinder when to stop and where walls are</param>
/// <param name="getH">Heuristic function for the tile</param>
/// <returns>The path, or <seealso cref="Enumerable.Empty{Tile}"/> if no path found</returns>
private IEnumerable <Tile> FindPathCustom(Tile start, CostFunc getCost, HeuristicFunc getH)
{
Dictionary <Tile, Node> nodes = new Dictionary <Tile, Node>();
List <Node> openList = new List <Node> {
this.GetNode(start, null, nodes, getCost, getH)
};
HashSet <string> closedList = new HashSet <string>();
while (openList.Any())
{
// Get current tile and close it
Node curNode = openList.First();
Tile curTile = curNode.Value;
openList.Remove(curNode);
closedList.Add(curTile.Id);
// Skip it if it's a wall and not the first tile
if (curNode.Cost < 0 && curTile != start)
{
continue;
}
// Check if done
// ReSharper disable once CompareOfFloatsByEqualityOperator
if (curNode.Cost == 0)
{
Stack <Tile> path = new Stack <Tile>();
while (curNode != null)
{
path.Push(curNode.Value);
curNode = curNode.Parent;
}
return(path);
}
// Add neighbors
Tile neighbor = curTile.TileNorth;
if (neighbor != null && !closedList.Contains(neighbor.Id))
{
openList.RemoveAll(n => n.Value.Id == neighbor.Id);
openList.Add(this.GetNode(neighbor, curNode, nodes, getCost, getH));
}
neighbor = curTile.TileEast;
if (neighbor != null && !closedList.Contains(neighbor.Id))
{
openList.RemoveAll(n => n.Value.Id == neighbor.Id);
openList.Add(this.GetNode(neighbor, curNode, nodes, getCost, getH));
}
neighbor = curTile.TileSouth;
if (neighbor != null && !closedList.Contains(neighbor.Id))
{
openList.RemoveAll(n => n.Value.Id == neighbor.Id);
openList.Add(this.GetNode(neighbor, curNode, nodes, getCost, getH));
}
neighbor = curTile.TileWest;
if (neighbor != null && !closedList.Contains(neighbor.Id))
{
openList.RemoveAll(n => n.Value.Id == neighbor.Id);
openList.Add(this.GetNode(neighbor, curNode, nodes, getCost, getH));
}
// Sort openList
openList.Sort((a, b) => (int)(a.F - b.F));
}
return(Enumerable.Empty <Tile>());
}
public AStar(HeuristicFunc heuristic)
{
Heuristic = heuristic;
}
