public static NodeGrid GetFilledNodeGrid(int width, int height)
{
var nodeGrid = new NodeGrid(width, height);
// Set each Node to a Wall
for (int x = 0; x < width; x++)
{
for (int y = 0; y < height; y++)
{
nodeGrid.Grid[x, y].Walkable = false;
}
}
return(nodeGrid);
}
public Stack <Node> FindPath(Vector2Int start, Vector2Int end)
{
this.Start = start;
this.End = end;
ChangeController.AddChange(new Change(start.x, start.y, GridNodeType.Start, GridNodeType.Empty));
ChangeController.AddChange(new Change(end.x, end.y, GridNodeType.End, GridNodeType.Empty));
Node startNode = NodeGrid.Grid[start.x, start.y];
Node endNode = NodeGrid.Grid[end.x, end.y];
_path = new Stack <Node>();
_openList = new List <Node>();
_closedList = new List <Node>();
Node current = startNode;
// add start node to Open List
startNode.State = NodeState.Open;
_openList.Add(startNode);
while (_openList.Count != 0)
{
// take the first node out (lowest F score)
current = _openList[0];
_openList.RemoveAt(0);
// add it to closed list & mark
current.State = NodeState.Closed;
ChangeController.AddChange(new Change(
current.Position.x, current.Position.y,
GridNodeType.Expanded, GridNodeType.Seen));
_closedList.Add(current);
// exit if this is the end node
if (current.Position == endNode.Position)
{
break;
}
// look at all adjacent nodes and add them to the open list if possible
Node[] adjacentNodes = this.NodeGrid.GetAdjacentNodesArray(current);
for (int i = 0; i < adjacentNodes.Length; i++)
{
Node node = adjacentNodes[i];
if (node != null && node.State == NodeState.None && node.Walkable)
{
// Setup node & calculate new costs
node.Parent = current;
node.DistanceToTarget = NodeGrid.Manhattan(node, endNode);
node.Cost = node.Weight + node.Parent.Cost;
// mark as open
node.State = NodeState.Open;
ChangeController.AddChange(new Change(node.Position.x, node.Position.y, GridNodeType.Seen,
GridNodeType.Empty));
// Insert the new node into the sorted open list in ascending order
int index = _openList.BinarySearch(node);
if (index < 0)
{
index = ~index;
}
_openList.Insert(index, node);
}
}
}
// construct path, if end was not closed return null
if (!_closedList.Exists(node => node.Position == endNode.Position))
{
return(null);
}
// if all good, return path
Node temp = _closedList[_closedList.IndexOf(current)];
if (temp == null)
{
return(null);
}
do
{
_path.Push(temp);
ChangeController.AddChange(new Change(temp.Position.x, temp.Position.y, GridNodeType.Path,
GridNodeType.Expanded));
temp = temp.Parent;
} while (temp != null && !temp.Equals(startNode));
// Fix start and end position being overriden
// TODO: Look into using a proper fix for this instead of a 'patch'.
ChangeController.RemovePositions(start, 1);
ChangeController.RemovePositions(end, 3);
return(_path);
}
public AStar(NodeGrid nodeGrid)
{
NodeGrid = nodeGrid;
ChangeController = new ChangeController(nodeGrid.RenderNodeTypes());
}
