void FindPath(Vector2 startPosition, Vector2 targetPosition)
{
PathfindingNode startNode = grid.GetNodeFromWorldPoint(startPosition);
PathfindingNode targetNode = grid.GetNodeFromWorldPoint(targetPosition);
List <PathfindingNode> openSet = new List <PathfindingNode>();
HashSet <PathfindingNode> closedSet = new HashSet <PathfindingNode>();
openSet.Add(startNode);
while (openSet.Count > 0)
{
PathfindingNode currentNode = openSet[0];
for (int i = 0; i < openSet.Count; i++)
{
if (openSet[i].fCost < currentNode.fCost ||
openSet[i].fCost == currentNode.fCost)
{
if (openSet[i].hCost < currentNode.hCost)
{
currentNode = openSet[i];
}
}
openSet.Remove(currentNode);
closedSet.Add(currentNode);
if (currentNode == targetNode)
{
RetracePath(startNode, targetNode);
return;
}
foreach (PathfindingNode neighbor in grid.GetNeighbors(currentNode))
{
if (!neighbor.isWalkable || closedSet.Contains(neighbor))
{
continue;
}
int newMovementCostToNeighbor = currentNode.gCost + GetDistance(currentNode, neighbor);
if (newMovementCostToNeighbor < neighbor.gCost || !openSet.Contains(neighbor))
{
neighbor.gCost = newMovementCostToNeighbor;
neighbor.hCost = GetDistance(neighbor, targetNode);
neighbor.parent = currentNode;
if (!openSet.Contains(neighbor))
{
openSet.Add(neighbor);
}
}
}
}
}
}
/// <summary>
/// Finds a path using A*
/// </summary>
/// <param name="startPosition">The starting position of the agent.</param>
/// <param name="targetPosition">The target position.</param>
private void PathAStar(Vector3 startPosition, Vector3 targetPosition)
{
//Get both nodes from the given world positions, start and target.
Node startNode = grid.NodeFromWorldPosition(startPosition);
Node targetNode = grid.NodeFromWorldPosition(targetPosition);
//Initialize open and closed set.
List <Node> openSet = new List <Node>();
HashSet <Node> closedSet = new HashSet <Node>();
bool success = false;
//First add starting node to the open set.
openSet.Add(startNode);
//Only loop while the open set has nodes.
while (openSet.Count > 0)
{
Node curNode = openSet[0];
for (int i = 1; i < openSet.Count; i++)
{
if ((openSet[i].fCost < curNode.fCost ||
openSet[i].fCost == curNode.fCost) && openSet[i].hCost < curNode.hCost)
{
//If the fCost of the node in open set is less than the current node.
curNode = openSet[i]; //Since the cost of that node is less, thats the node we want. (Shortest path)
}
} //Now that the current node is set to the node with the lowest fCost, remove it from open set and put in closed set.
openSet.Remove(curNode);
closedSet.Add(curNode);
if (curNode == targetNode)
{
//If the current node is equal to the target node, we reached the destination.
success = true;
break;
}
//Get the neighbors of the current node.
List <Node> neighbors = grid.GetNeighbors(curNode);
//Loops through each of the current nodes neighbors.
foreach (Node neighborNode in neighbors)
{
//if the neighbor is not walkable or the neighbor is in the closed set, skip to next neighbor.
if (!neighborNode.walkable || closedSet.Contains(neighborNode))
{
continue;
}
int newCost = curNode.gCost + GetManhattenDistance(neighborNode, targetNode);
if (newCost < neighborNode.gCost || !openSet.Contains(neighborNode))
{
//Assign new values to neighbor node.
neighborNode.gCost = newCost;
neighborNode.hCost = GetManhattenDistance(neighborNode, targetNode);
neighborNode.parent = curNode;
//If a neighboring node is not in the open set add it to be explored.
if (!openSet.Contains(neighborNode))
{
openSet.Add(neighborNode);
}
}
}
}
Vector3[] pathPoints = new Vector3[0];
if (success)
{
pathPoints = GetPath(startNode, targetNode);
}
rm.FinishedProcessing(pathPoints, success);
}
