/// <summary>
/// Coroutine to find the best path according to the DnD* algorithm.
/// </summary>
/// <param name="start">Node which starts the path.</param>
/// <param name="end">Node that ends the path.</param>
private IEnumerator FindPath(Node start, Node end)
{
Node[] nodePath = new Node[0];
bool pathSuccess = false;
Node startNode = start;
Node targetNode = end;
// If the target is able to be pathed to...
if (targetNode.IsWalkable())
{
// Prepare sets of nodes for storing information
List <Node> openSet = new List <Node>(grid.length * grid.width); // creates open list of max size equal to max number of tiles in grid
HashSet <Node> closedSet = new HashSet <Node>();
openSet.Add(startNode);
// While there are still nodes left to process...
while (openSet.Count > 0)
{
Node currentNode = openSet[0];
openSet.RemoveAt(0);
closedSet.Add(currentNode);
// Check to see if the node being processed is the target
if (currentNode == targetNode)
{
pathSuccess = true;
break;
}
// Get connections from this node
List <Node> connections = currentNode.connections;
/// Check every connection for the best next node to check
foreach (Node connection in connections)
{
if (!connection.IsWalkable() || closedSet.Contains(connection))
{
// we skip over this connecting node
continue;
}
int newMoveCost = currentNode.gCost + Heuristic(currentNode, connection);
if (newMoveCost < connection.gCost || !openSet.Contains(connection))
{
connection.gCost = newMoveCost;
connection.hCost = Heuristic(connection, targetNode);
connection.fromNode = currentNode;
if (!openSet.Contains(connection))
{
openSet.Add(connection);
}
}
}
}
}
yield return(null);
if (pathSuccess)
{
nodePath = RetracePath(startNode, targetNode);
}
else
{
nodePath = null;
}
pathRequester.FreePathfinder(this, nodePath, pathSuccess, endededOnDiagonal);
}
