/// <summary>
/// Internal function that implements the path-finding algorithm.
/// </summary>
/// <param name="grid">Grid to search.</param>
/// <param name="startPos">Starting position.</param>
/// <param name="targetPos">Ending position.</param>
/// <param name="distance">The type of distance, Euclidean or Manhattan.</param>
/// <param name="ignorePrices">If true, will ignore tile price (how much it "cost" to walk on).</param>
/// <returns>List of grid nodes that represent the path to walk.</returns>
private static List <Node> _ImpFindPath(PathfindGrid grid, Point startPos, Point targetPos, DistanceType distance = DistanceType.Euclidean, bool ignorePrices = false)
{
Node startNode = grid.nodes[startPos.x, startPos.y];
Node targetNode = grid.nodes[targetPos.x, targetPos.y];
List <Node> openSet = new List <Node>();
HashSet <Node> closedSet = new HashSet <Node>();
openSet.Add(startNode);
while (openSet.Count > 0)
{
Node currentNode = openSet[0];
for (int i = 1; i < openSet.Count; i++)
{
if (openSet[i].fCost < currentNode.fCost || openSet[i].fCost == currentNode.fCost && openSet[i].hCost < currentNode.hCost)
{
currentNode = openSet[i];
}
}
openSet.Remove(currentNode);
closedSet.Add(currentNode);
if (currentNode == targetNode)
{
return(RetracePath(grid, startNode, targetNode));
}
foreach (Node neighbour in grid.GetNeighbours(currentNode, distance))
{
if (!neighbour.walkable || closedSet.Contains(neighbour))
{
continue;
}
int newMovementCostToNeighbour = currentNode.gCost + GetDistance(currentNode, neighbour) * (ignorePrices ? 1 : (int)(10.0f * neighbour.price));
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);
}
}
}
}
return(null);
}
IEnumerator FindPath(Vector3 startPos, Vector3 targetPos)
{
Vector3[] waypoints = new Vector3[0];
bool pathSuccess = false;
Node startNode = _grid.NodeFromWorldInput(startPos);
Node targetNode = _grid.NodeFromWorldInput(targetPos);
if (startNode.Walkable && targetNode.Walkable)
{
Heap <Node> openSet = new Heap <Node>(_grid.MaxSize);
HashSet <Node> closedSet = new HashSet <Node>();
openSet.Add(startNode);
while (openSet.Count > 0)
{
Node currentNode = openSet.RemoveFirst();
closedSet.Add(currentNode);
if (currentNode == targetNode)
{
pathSuccess = true;
break;
}
foreach (Node neighbour in _grid.GetNeighbours(currentNode))
{
if (!neighbour.Walkable || closedSet.Contains(neighbour))
{
continue;
}
int newMoveCostToNeighbour = currentNode.GCost + GetDistance(currentNode, neighbour);
if (newMoveCostToNeighbour < neighbour.GCost ||
!openSet.Contains(neighbour))
{
neighbour.GCost = newMoveCostToNeighbour;
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.FinishedProcessingPath(waypoints, pathSuccess);
}