//Check if the search algorithm is ready to terminate.
private bool terminateSearch(Node endNode)
{
Console.WriteLine("openList.Count = " + openList.Count);
if (openList.Count != 0)
{
ClosedListItem goal = null;
//Find the goal node in the closedList
foreach (ClosedListItem item in closedList)
{
if (item.Node.Index == endNode.Index)
{
goal = item;
}
}
//If the smallest costSoFar element in the openList is greater than the goal item in the closedList
if (goal != null && openList[0].CostSoFar > goal.CostSoFar)
{
return(true);
}
return(false);
}
return(true);
}
public List <Node> GetPath(Node startNode, Node endNode, Heuristic heuristic)
{
closedList.Clear();
openList.Clear();
//Create the first entry in the openList
openList.Add(new OpenListItem(startNode, 0.0f, new List <Node>(), getEstimatedCostSoFar(startNode, endNode, heuristic)));
OpenListItem currentItem, childItem;
List <Node> childItemConnections;
bool addToClosedList = true;
bool childItemUpdated = false;
//Keep running until terminateSearch() returns true
while (!terminateSearch(endNode))
{
//Grab the first element in the openList
currentItem = openList[0];
openList.RemoveAt(0);
//Add all children to the openList ordered by increasing estimatedTotalCost
foreach (Connection childConnection in TileGenerator.Graph.getConnectedNodes(currentItem.Node))
{
if (!currentItem.ConnectionNodes.Contains(childConnection.ToNode))
{
//Add the parent's connection chain to the child
childItemConnections = new List <Node>(currentItem.ConnectionNodes);
//Add the connection from the parent to the child
childItemConnections.Add(childConnection.ToNode);
//Create an OpenListItem for the child
childItem = new OpenListItem(childConnection.ToNode, currentItem.CostSoFar + childConnection.Cost, childItemConnections, getEstimatedCostSoFar(childConnection.ToNode, endNode, heuristic));
//Check if the childItem's node already exists in the openList
for (int i = 0; i < openList.Count; i++)
{
//Check if both items have the same nodes
if (childItem.Node.Index == openList[i].Node.Index)
{
// Keep the more optimal path
if (childItem.CostSoFar < openList[i].CostSoFar)
{
openList[i] = childItem;
childItemUpdated = true;
break;
}
}
}
if (!childItemUpdated)
{
insertIntoOpenList(openList, childItem);
}
childItemUpdated = false; //Reset flag
}
}
//Check if it exists on the closed list
for (int i = 0; i < closedList.Count; i++)
{
//Check if both items have the same nodes
if (currentItem.Node.Index == closedList[i].Node.Index)
{
// Keep the more optimal path
if (currentItem.CostSoFar < closedList[i].CostSoFar)
{
closedList[i] = new ClosedListItem(currentItem.Node, currentItem.CostSoFar, currentItem.ConnectionNodes);
addToClosedList = false;
break;
}
}
}
if (addToClosedList)
{
//Add currentItem to the closedList
closedList.Add(new ClosedListItem(currentItem.Node, currentItem.CostSoFar, currentItem.ConnectionNodes));
}
addToClosedList = true; //Reset flag
}
//Return the goalItem's connection list on the closedList
foreach (ClosedListItem item in closedList)
{
if (item.Node.Index == endNode.Index)
{
return(item.ConnectionNodes);
}
}
return(null);
}