/// <summary>
/// Used for A*
/// </summary>
/// <param name="start"></param>
/// <param name="end"></param>
/// <returns></returns>
public float CalculateTotal(qpNode start, qpNode end)
{
_h = CalculateH(end);
if (_parent != null)
{
_g = CalculateG(_parent) + _parent.GetG();
}
else
{
_g = 1;
}
_total = _g + _h;
return(_total);
}
/// <summary>
/// Performs an A* algorithm
/// </summary>
/// <param name="start">Starting node</param>
/// <param name="end">Destination Node</param>
/// <returns>The fastest path from start node to the end node</returns>
protected List <qpNode> AStar(qpNode start, qpNode end)
{
Debug.Log("astar from " + start.GetCoordinate() + " to " + end.GetCoordinate());
List <qpNode> path = new List <qpNode>(); //will hold the final path
bool complete = (end == null || start == null) ? true : false; //Regulates the main while loop of the algorithm
List <qpNode> closedList = new List <qpNode>(); //Closed list for the best candidates.
List <qpNode> openList = new List <qpNode>(); //Open list for all candidates(A home for all).
qpNode candidate = start; //The current node candidate which is being analyzed in the algorithm.
openList.Add(start); //Start node is added to the openlist
if (start == null || end == null)
{
return(null); //algoritmen cannot be executed if either start or end node are null.
}
int astarSteps = 0;
while (openList.Count > 0 && !complete) //ALGORITHM STARTS HERE.
{
astarSteps++;
if (candidate == end) //If current candidate is end, the algorithm has been completed and the path can be build.
{
DestinationNode = end;
complete = true;
bool pathComplete = false;
qpNode node = end;
while (!pathComplete)
{
path.Add(node);
if (node == start)
{
pathComplete = true;
}
node = node.GetParent();
}
}
List <qpNode> allNodes = (DiagonalMovement ? candidate.Contacts : candidate.NonDiagonalContacts);
List <qpNode> potentialNodes = new List <qpNode>();
foreach (qpNode n in allNodes)
{
if (n.traverseable)
{
potentialNodes.Add(n);
}
}
foreach (qpNode n in potentialNodes)
{
bool inClosed = closedList.Contains(n);
bool inOpen = openList.Contains(n);
//Mark candidate as parent if not in open nor closed.
if (!inClosed && !inOpen)
{
n.SetParent(candidate);
openList.Add(n);
}
//But if in open, then calculate which is the better parent: Candidate or current parent.
else if (inOpen)
{
float math2 = n.GetParent().GetG();
float math1 = candidate.GetG();
if (math2 > math1)
{
//candidate is the better parent as it has a lower combined g value.
n.SetParent(candidate);
}
}
}
//Calculate h, g and total
if (openList.Count == 0)
{
break;
}
openList.RemoveAt(0);
if (openList.Count == 0)
{
break;
}
//the below one-lined for loop,if conditional and method call updates all nodes in openlist.
for (int i = 0; i < openList.Count; i++)
{
openList[i].CalculateTotal(start, end);
}
openList.Sort(delegate(qpNode node1, qpNode node2)
{
return(node1.GetTotal().CompareTo(node2.GetTotal()));
});
candidate = openList[0];
closedList.Add(candidate);
}
Debug.Log("astar completed in " + astarSteps + " steps. Path found:" + complete);
path.Reverse();
return(path);
}
