/// <summary>
/// call this to plan a path between points
/// </summary>
/// <param name="begin"></param>
/// <param name="end"></param>
/// <returns></returns>
public Route FindRoute(Location begin, Location end)
{
HashSet<MapTile> tilesToReset = new HashSet<MapTile>();//all tiles that need to be reset
MapTile mapEnd = Map[end.Row, end.Col];
MapTile mapBegin = Map[begin.Row, begin.Col];
tilesToReset.Add(mapBegin);
mapBegin.CostKnown = 0;
mapBegin.Heuristic = Globals.state.GetDistance(begin, end);
mapBegin.CostEstimate = mapBegin.CostKnown + mapBegin.Heuristic;
MinHeap<MapTile> OpenSet = new MinHeap<MapTile>();
OpenSet.Add(mapBegin);
while (!OpenSet.IsEmpty)
{
MapTile current = OpenSet.ExtractMin();
if (current == mapEnd)
return BuildRoute(mapEnd, tilesToReset);//reset after the oath is build, we need those pi pointers
foreach (Direction d in (Direction[])Enum.GetValues(typeof(Direction)))
{
Location tile = Globals.state.GetDestination(current.GetLocation, d);
MapTile neighbour = Map[tile.Row, tile.Col];
bool succesful = Relax(current, neighbour, mapEnd);
tilesToReset.Add(neighbour);//hashset will not contain duplicates
if (!neighbour.InOpenSet && succesful)
{
OpenSet.Add(neighbour);
neighbour.InOpenSet = true;//openset is a min heap, no O(1) lookup so store this in the tile
}
else
{
if (neighbour.InOpenSet && succesful)
{
OpenSet.ChangeKey(neighbour, neighbour.CostEstimate);
}
}
}
}
foreach (MapTile t in tilesToReset)//no route found, still need to reset
t.Reset();
return null;
}
