public Pathfinder(int width, int height)
{
//use our own tiles independent of that game state
Map = new MapTile[height, width];
for (int col = 0; col < width; col++)
for (int row = 0; row < height; row++)
Map[row, col] = new MapTile(col, row);
}
//Key: u = unknown, d = dirt, w = water/wall
public Map(int width, int height)
{
w = width;
h = height;
map = new MapTile[width, height];
//Whole map is unknown at creation
for (int x = 0; x < width; x++)
{
for (int y = 0; y < height; y++)
{
map[x, y] = new MapTile();
}
}
}
/// <summary>
/// when the pathfinding has terminated this builds the path, returns the Route object and readies the map for the next pathfinding call
/// </summary>
/// <param name="end"></param>
/// <param name="toReset"></param>
/// <returns></returns>
private Route BuildRoute(MapTile end, HashSet<MapTile> toReset)
{
//pointers are end -> begin so the path comes in reverse
Location[] Path = new Location[end.CostKnown+1];//tiles in a path eqaul to the cost + 1 (hops between tile +1), use this to avoid having to reverse the path in O(n)
MapTile current = end;
while(current != null)
{
Path[current.CostKnown] = current.GetLocation;
current = current.Parent;
}
Location first = Path[0];
foreach (MapTile t in toReset)//ready the map for next pathfinding call
t.Reset();
return new Route(first, end.GetLocation, Path);
}
public void Reset()
{
h = 10000;
g = 10000;
f = 10000;
InOpen = false;
Pi = null;
}
/// <summary>
/// relaxes the edge between two nodes, this needs to happen for all neighbours of source.
/// </summary>
/// <param name="source"></param>
/// <param name="neighbour"></param>
/// <param name="destination"></param>
/// <returns></returns>
private bool Relax(MapTile source, MapTile neighbour, MapTile destination)
{
float heuristic = Globals.state.GetDistance(neighbour.GetLocation, destination.GetLocation);//manhattan distance as heuristic
bool betterRoute = neighbour.CostEstimate > source.CostKnown + 1 + heuristic;
bool passable = Globals.state.GetIsPassable(neighbour.GetLocation);
if (betterRoute && passable)
{
neighbour.CostKnown = source.CostKnown + 1;
neighbour.CostEstimate = neighbour.CostKnown + heuristic;
neighbour.Heuristic = heuristic;
neighbour.Parent = source;
return true;
}
return false;
}
