/* Path Finding Algorithm
*
* openSet (set of nodes to be evaluated)
* closeSet (set of nodes already evaluated)
* add start node to openSet
*
* loop
* currentNode = node in openSet with lowest f_Cost
* remove currentNode from openSet
* add currentNode to closeSet
*
* if currentNode is the targetNode (path has been found)
* return
* foreach neighbour of currentNode
* if neighbour is not traversable or neighbour is in closeSet
* skip to next neighbour
* if new path to neighbour is shorter OR neighbour is not in openSet
* set f_Cost of neighbour
* set parent of neighbour to currentNode
* if neighbour is not in openSet
* add neighbour to openSet
*/
IEnumerator FindPath(Vector3 _startPos, Vector3 _targetPos)
{
Stopwatch sw = new Stopwatch();
sw.Start();
Vector3[] wayPoints = new Vector3[0];
bool pathSuccess = false;
Node startNode = grid.NodeFromWorldPoint(_startPos);
Node targetNode = grid.NodeFromWorldPoint(_targetPos);
if (startNode.walkable && targetNode.walkable)
{
Heap <Node> openSet = new Heap <Node>(grid.MaxSize);
HashSet <Node> closeSet = new HashSet <Node>();
openSet.Add(startNode);
while (openSet.Count > 0)
{
Node currentNode = openSet.RemoveFirst();
closeSet.Add(currentNode);
if (currentNode == targetNode)
{
sw.Stop();
print("Path found: " + sw.ElapsedMilliseconds + " ms");
pathSuccess = true;
break;
}
List <Node> neighbours = grid.GetNeighbours(currentNode);
foreach (Node neighbour in neighbours)
{
if (!neighbour.walkable || closeSet.Contains(neighbour))
{
continue;
}
int newMovementCostToNeighbour = currentNode.gCost + GetDistance(currentNode, neighbour) + neighbour.movementPenalty;
if (newMovementCostToNeighbour < neighbour.gCost || !openSet.Contains(neighbour))
{
neighbour.gCost = newMovementCostToNeighbour;
neighbour.hCost = GetDistance(neighbour, targetNode);
neighbour.parent = currentNode;
if (!openSet.Contains(neighbour))
{
openSet.Add(neighbour);
}
else
{
openSet.UpdateItem(neighbour);
}
}
}
}
}
yield return(null);
if (pathSuccess)
{
wayPoints = RetracePath(startNode, targetNode);
}
requestManager.FinnishedProcessingPath(wayPoints, pathSuccess);
}