public static List<Vector2> FindPath(Vector2 startTile, Vector2 endTile, TileMap mapRef)
{
if (!mapRef.MapCellAt(startTile).Walkable || !mapRef.MapCellAt(endTile).Walkable)
{
return null;
}
OpenList.Clear();
NodeCosts.Clear();
nodeStatus.Clear();
var endNode = new PathNode(null, null, endTile, mapRef.MapCellAt(endTile).CenterPosition, 0);
var startNode = new PathNode(null, endNode, startTile, mapRef.MapCellAt(startTile).CenterPosition, 0);
AddNodeToOpenList(startNode);
while (OpenList.Count > 0)
{
var currentNode = OpenList[OpenList.Count - 1];
if (currentNode.IsEqualToNode(endNode))
{
var bestPath = new List<Vector2>();
while (currentNode != null)
{
bestPath.Insert(0, currentNode.GridLocation);
currentNode = currentNode.ParentNode;
}
return bestPath;
}
OpenList.Remove(currentNode);
NodeCosts.Remove(currentNode.GridLocation);
foreach (
var possibleNode in
FindAdjacentNodes(currentNode, endNode, mapRef))
{
if (nodeStatus.ContainsKey(possibleNode.GridLocation))
{
if (nodeStatus[possibleNode.GridLocation] ==
NodeStatus.Closed)
{
continue;
}
if (
nodeStatus[possibleNode.GridLocation] ==
NodeStatus.Open)
{
if (possibleNode.TotalCost >=
NodeCosts[possibleNode.GridLocation])
{
continue;
}
}
}
AddNodeToOpenList(possibleNode);
}
nodeStatus[currentNode.GridLocation] = NodeStatus.Closed;
}
return null;
}
public PathNode(
PathNode parentNode,
PathNode endNode,
Vector2 gridLocation,
Vector2 cellCenterPosition,
float cost)
{
_cellCenterPosition = cellCenterPosition;
ParentNode = parentNode;
GridLocation = gridLocation;
EndNode = endNode; DirectCost = cost;
if (endNode != null)
{
TotalCost = DirectCost + LinearCost();
}
}
public bool IsEqualToNode(PathNode node)
{
return (GridLocation == node.GridLocation);
}
private static void AddNodeToOpenList(PathNode node)
{
int index = 0;
float cost = node.TotalCost;
while ((OpenList.Count() > index) &&
(cost < OpenList[index].TotalCost))
{
index++;
}
OpenList.Insert(index, node);
NodeCosts[node.GridLocation] = node.TotalCost;
nodeStatus[node.GridLocation] = NodeStatus.Open;
}
private static IEnumerable<PathNode> FindAdjacentNodes( PathNode currentNode, PathNode endNode, TileMap mapRef)
{
var adjacentNodes = new List<PathNode>();
var current = currentNode.GridLocation;
var v2Pointer = current.WalkTo(Direction.N);
if(mapRef.MapCellAt(v2Pointer).Walkable)
adjacentNodes.Add(new PathNode(currentNode, endNode, v2Pointer, mapRef.MapCellAt(v2Pointer).CenterPosition, currentNode.DirectCost + PathFinder.DirectCostNs));
v2Pointer = current.WalkTo(Direction.NE);
if (mapRef.MapCellAt(v2Pointer).Walkable)
adjacentNodes.Add(new PathNode(currentNode, endNode, v2Pointer, mapRef.MapCellAt(v2Pointer).CenterPosition, currentNode.DirectCost + PathFinder.DirectCostDiagonaly));
v2Pointer = current.WalkTo(Direction.E);
if (mapRef.MapCellAt(v2Pointer).Walkable)
adjacentNodes.Add(new PathNode(currentNode, endNode, v2Pointer, mapRef.MapCellAt(v2Pointer).CenterPosition, currentNode.DirectCost + PathFinder.DirectCostEw));
v2Pointer = current.WalkTo(Direction.SE);
if (mapRef.MapCellAt(v2Pointer).Walkable)
adjacentNodes.Add(new PathNode(currentNode, endNode, v2Pointer, mapRef.MapCellAt(v2Pointer).CenterPosition, currentNode.DirectCost + PathFinder.DirectCostDiagonaly));
v2Pointer = current.WalkTo(Direction.S);
if (mapRef.MapCellAt(v2Pointer).Walkable)
adjacentNodes.Add(new PathNode(currentNode, endNode, v2Pointer, mapRef.MapCellAt(v2Pointer).CenterPosition, currentNode.DirectCost + PathFinder.DirectCostNs));
v2Pointer = current.WalkTo(Direction.SW);
if (mapRef.MapCellAt(v2Pointer).Walkable)
adjacentNodes.Add(new PathNode(currentNode, endNode, v2Pointer, mapRef.MapCellAt(v2Pointer).CenterPosition, currentNode.DirectCost + PathFinder.DirectCostDiagonaly));
v2Pointer = current.WalkTo(Direction.W);
if (mapRef.MapCellAt(v2Pointer).Walkable)
adjacentNodes.Add(new PathNode(currentNode, endNode, v2Pointer, mapRef.MapCellAt(v2Pointer).CenterPosition, currentNode.DirectCost + PathFinder.DirectCostEw));
v2Pointer = current.WalkTo(Direction.NW);
if (mapRef.MapCellAt(v2Pointer).Walkable)
adjacentNodes.Add(new PathNode(currentNode, endNode, v2Pointer, mapRef.MapCellAt(v2Pointer).CenterPosition, currentNode.DirectCost + PathFinder.DirectCostDiagonaly));
return adjacentNodes;
}