Ejemplo n.º 1
0
    private IEnumerator FindPath(Vector2 startPos, Vector2 targetPos)
    {
        //Diagnostic tools
        Stopwatch sw = new Stopwatch();

        sw.Start();

        Vector2[] waypoints   = new Vector2[0];
        bool      pathSuccess = false;


        //Initialize the open set and closed set and stick
        PathNode startNode  = pathGrid.NodeFromWorldPoint(startPos);
        PathNode targetNode = pathGrid.NodeFromWorldPoint(targetPos);

        if (startNode.Traversable && targetNode.Traversable)
        {
            //List<PathNode> openSet = new List<PathNode>();
            Heap <PathNode>    openSet   = new Heap <PathNode>(pathGrid.MaxSize);
            HashSet <PathNode> closedSet = new HashSet <PathNode>();
            openSet.Add(startNode);

            //Main loop for search algo
            while (openSet.Count > 0)
            {
                /*
                 * Causing issues when replaced with heap - stack overflows
                 *
                 * Note from a youtube comment: duh!!!
                 * +ReMi001 In the Node class, when you implement HeapIndex, be very careful and in get and set write heapIndex, not HeapIndex.
                 *
                 */
                PathNode currentNode = openSet.RemoveFirst();
                closedSet.Add(currentNode);

                if (currentNode == targetNode)
                {
                    sw.Stop();
                    print("Path found: " + sw.ElapsedMilliseconds + "ms");
                    pathSuccess = true;
                    break;
                }

                foreach (PathNode neighbour in pathGrid.FindNeighbours(currentNode))
                {
                    if (!neighbour.Traversable || closedSet.Contains(neighbour))
                    {
                        continue;
                    }

                    int newMovementCostToNeighbour = currentNode.GCost + this.CalculateDistance(currentNode, neighbour) + neighbour.MovementPenalty;
                    if (newMovementCostToNeighbour < neighbour.GCost || !openSet.Contains(neighbour))
                    {
                        neighbour.GCost  = newMovementCostToNeighbour;
                        neighbour.HCost  = this.CalculateDistance(currentNode, targetNode);
                        neighbour.Parent = currentNode;

                        if (!openSet.Contains(neighbour))
                        {
                            openSet.Add(neighbour);
                        }
                        else
                        {
                            openSet.UpdateItem(neighbour);
                        }
                    }
                }
            }
        }
        yield return(null); //Makes the co-routine wait one frame before returning?

        if (pathSuccess)
        {
            waypoints = this.RetracePath(startNode, targetNode);
        }
        requestManager.FinishedProcessingPath(waypoints, pathSuccess);
    }