/// <summary>
/// this method will create the path that the object has to take.
/// </summary>
/// <param name="startPosition"></param>
/// <param name="endPosition"></param>
IEnumerator FindPath(Vector3 startPosition, Vector3 endPosition)
{
Stopwatch sw = new Stopwatch();
sw.Start();
Vector3[] waypoints = new Vector3[0];
bool PathSuccess = false;
//converts the vector3 position to the node on the map.
Node startNode = Grid.NodeFromWorldPoint(startPosition);
Node endNode = Grid.NodeFromWorldPoint(endPosition);
//list for containing all the open nodes.
Heap <Node> openSet = new Heap <Node>(Grid.MaxSize);
//HashSEt holds a set of objects making it easy to check if a certain object is already in it.
HashSet <Node> closedSet = new HashSet <Node>();
openSet.Add(startNode);
while (openSet.Count > 0)
{
//find node in open set with lowest f cost
Node currentNode = openSet.RemoveFirst();
closedSet.Add(currentNode);
//if the node found with lowest fcost is the target, return.
if (currentNode == endNode)
{
//if path is found, stop the stopWatch
sw.Stop();
print("path found " + sw.ElapsedMilliseconds + "ms");
//if path is found, it is successful.
PathSuccess = true;
//if pathFound, exit out of the loop.
break;
}
foreach (Node neighbor in Grid.getNeighbors(currentNode))
{
//if the neighbor is not traversable or is already in the closed set, skip
if (!neighbor.walkable || closedSet.Contains(neighbor))
{
continue;
}
//add the movement penalty to the cost to the neighbor too.
int newMovementCostToNeighbor = currentNode.gCost + getDistance(currentNode, neighbor) + neighbor.movementPenalty;
// if the distance between the current node and the neighbor is less than the gcost or neighbor is not in the open list
if (newMovementCostToNeighbor < neighbor.gCost || !openSet.Contains(neighbor))
{
neighbor.gCost = newMovementCostToNeighbor;
neighbor.hCost = getDistance(neighbor, endNode);
neighbor.parent = currentNode;
if (!openSet.Contains(neighbor))
{
openSet.Add(neighbor);
}
else
{
openSet.UpdateItem(neighbor);
}
}
}
}
//makes it wait for one frame.
yield return(null);
//after finding the path:
//if a path has been found, store each node of the path into the array.
if (PathSuccess)
{
waypoints = ReTracePath(startNode, endNode);
}
//the reqested data has been obtained.Process is finished
requestManager.FinishedProcessingPath(waypoints, PathSuccess);
}
