List<PathNode> FindAdjacentNodes(PathNode currentNode, PathNode endNode)
{
List<PathNode> adjacentNodes = new List<PathNode>();
int X = currentNode.GridX;
int Y = currentNode.GridY;
bool upLeft = true;
bool upRight = true;
bool downLeft = true;
bool downRight = true;
if ((X > 0) && (TileMap.CellIsPassable(X - 1, Y)))
{
adjacentNodes.Add(new PathNode(currentNode, endNode, new Vector2(X - 1, Y), CostStraight + currentNode.DirectCost));
}
else
{
upLeft = false;
downLeft = false;
}
if ((X < TileMap.MapWidth - 1) && (TileMap.CellIsPassable(X + 1, Y)))
{
adjacentNodes.Add(new PathNode(currentNode, endNode, new Vector2(X + 1, Y), CostStraight + currentNode.DirectCost));
}
else
{
upRight = false;
downRight = false;
}
if ((Y > 0) && (TileMap.CellIsPassable(X, Y - 1)))
{
adjacentNodes.Add(new PathNode(currentNode, endNode, new Vector2(X, Y - 1), CostStraight + currentNode.DirectCost));
}
else
{
upLeft = false;
upRight = false;
}
if ((Y < TileMap.MapHeight - 1) && (TileMap.CellIsPassable(X, Y + 1)))
{
adjacentNodes.Add(new PathNode(currentNode, endNode, new Vector2(X, Y + 1), CostStraight + currentNode.DirectCost));
}
else
{
downLeft = false;
downRight = false;
}
if ((upLeft) && (TileMap.CellIsPassable(X - 1, Y - 1)))
{
adjacentNodes.Add(new PathNode(currentNode, endNode, new Vector2(X - 1, Y - 1), CostDiagonal + currentNode.DirectCost));
}
if ((upRight) && (TileMap.CellIsPassable(X + 1, Y - 1)))
{
adjacentNodes.Add(new PathNode(currentNode, endNode, new Vector2(X + 1, Y - 1), CostDiagonal + currentNode.DirectCost));
}
if ((downLeft) && (TileMap.CellIsPassable(X - 1, Y + 1)))
{
adjacentNodes.Add(new PathNode(currentNode, endNode, new Vector2(X - 1, Y + 1), CostDiagonal + currentNode.DirectCost));
}
if ((downRight) && (TileMap.CellIsPassable(X + 1, Y + 1)))
{
adjacentNodes.Add(new PathNode(currentNode, endNode, new Vector2(X + 1, Y + 1), CostDiagonal + currentNode.DirectCost));
}
return adjacentNodes;
}
public List<Vector2> FindPath(Vector2 startTile, Vector2 endTile)
{
if (!TileMap.CellIsPassable(endTile) || !TileMap.CellIsPassable(startTile))
{
return null;
}
openList.Clear();
nodeCosts.Clear();
nodeStatus.Clear();
PathNode startNode;
PathNode endNode;
endNode = new PathNode(null, null, endTile, 0);
startNode = new PathNode(null, endNode, startTile, 0);
AddNodeToOpenList(startNode);
while (openList.Count > 0)
{
PathNode currentNode = openList[openList.Count - 1];
if (currentNode.IsEqualToNode(endNode))
{
List<Vector2> 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 (PathNode possibleNode in FindAdjacentNodes(currentNode, endNode))
{
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;
}