// Get the path to follow using a A* start algorithm
public Queue <Node> GetPathWithAStarAlgo(Vector2 startPos, Vector2 targetPos)
{
List <Node> openList = new List <Node>();
List <Node> closeList = new List <Node>();
Node startNode = grid.GetNodeFromWorldPosition(startPos);
Node targetNode = grid.GetNodeFromWorldPosition(targetPos);
// First step
// Update H value of all the nodes in the grid
grid.ResetNodesParent();
grid.ScanObstacles();
if (targetNode == null || startNode == null || targetNode.isWall)
{
return(null);
}
foreach (Node node in grid.GetNodes())
{
if (node != null)
{
node.UpdateHCost(targetNode);
}
}
Node currentNode = startNode;
int cpt = 0;
while (currentNode != targetNode)
{
openList.Remove(currentNode);
closeList.AddUnique(currentNode);
// Add neighbour nodes to the open list if they are not in the closeList
List <Node> neighbours = grid.GetFreeNeighbours(currentNode);
foreach (Node node in neighbours)
{
if (!closeList.Contains(node))
{
// We change the parent node if it is a shorter way to access
if (node.parent == null || node.GCost > node.ComputeGCostFrom(currentNode))
{
node.parent = currentNode;
}
openList.AddUnique(node);
}
}
currentNode = GetBestCandidate(openList, targetNode);
cpt++;
if (cpt > limitStepAlgo)
{
Debug.Log("Reached iteration limit during pathFinding algorithm");
return(null);
}
}
//Debug.Log("number of iterations: " + cpt);
currentPath = GetPathFromNode(currentNode);
return(currentPath);
}