//Checks if a given position is walkable (is not a wall)
private static bool IsValid(Maze maze, Vector2Int pos)
{
return(maze.IsWalkable(pos));
}
public static List <Vector2Int> FindPath(Maze maze)
{
List <Vector2Int> path = new List <Vector2Int>();
Vector2Int start = maze.GetStartTile();
start.x += 1;
Vector2Int end = maze.GetEndTile();
end.x -= 1;
//The path can't exist
if (!maze.IsValid(start) || !maze.IsValid(end))
{
return(path);
}
//Initialize all the nodes
Cell[,] tiles = maze.GetTiles();
Node[,] nodes = new Node[tiles.GetLength(0), tiles.GetLength(1)];
for (int i = 0; i < tiles.GetLength(0); i++)
{
for (int j = 0; j < tiles.GetLength(1); j++)
{
bool solid = tiles[i, j].IsWalkable();
nodes[i, j] = new Node(new Vector2Int(i, j), solid);
}
}
Node startNode = new Node(start, tiles[start.x, start.y].IsWalkable());
Node endNode = new Node(end, tiles[end.x, end.y].IsWalkable());
//The path can't exist
if (startNode.IsSolid() || endNode.IsSolid())
{
return(path);
}
// Initialize both open and closed list
List <Node> openList = new List <Node>();
List <Node> closedList = new List <Node>();
// Add the start node
openList.Add(startNode);
// Loop until we find the end
while (openList.Count != 0)
{
// Get the current node
Node current = FindLeastFValueNode(openList);
openList.Remove(current);
// Found the goal
if (HasFoundTheGoal(current, endNode))
{
while (current != null)
{
path.Add(current.pos);
current = current.parent;
}
path.Reverse();
return(path);
}
// Generate children
current.GenerateChildren(current, nodes);
foreach (Node child in current.GetChildren())
{
// Child is in the closedList
if (ContainsNode(closedList, child))
{
continue;
}
if (child.IsSolid())
{
continue;
}
// Create the f, g and h values
child.g = current.g + 1;
child.h = GetDistance(child, endNode);
child.f = child.g + child.h;
// Child is already in openList
List <Node> othersContained = child.GetNodesAtSamePosition(openList);
if (ContainsLeastGValue(othersContained, child))
{
continue;
}
// Add the child to the openList
if (!ContainsNode(openList, child))
{
openList.Add(child);
}
child.parent = current;
}
closedList.Add(current);
}
return(path);
}
