/// <summary>
/// Returns an enumerator that creates a maze by linking cells using the HuntAndKill algorithm
/// </summary>
/// <param name="service"></param>
/// <returns></returns>
public override IEnumerator CreateMazeRoutine(MazeGenerationService service)
{
//create data structures necessary for algorithm to work
List <MazeCell> visited = new List <MazeCell>();
//set starting point
MazeCell walker = service.RootCell;
walker.MarkAsVisited();
visited.Add(walker);
//loop untill all cells have been visited
long totalCells = service.Cells.LongLength;
while (visited.Count != totalCells)
{
//check if the current walker has unvisited neighbours
List <MazeCell> unvisitedNeighbours = service.GetUnVisitedNeighbours(walker);
if (unvisitedNeighbours.Count > 0)
{
//pick a random unvisited neighbour and mark it as visited
MazeCell randomUnvisitedNeighbour = unvisitedNeighbours[Random.Range(0, unvisitedNeighbours.Count)];
randomUnvisitedNeighbour.MarkAsVisited();
visited.Add(randomUnvisitedNeighbour);
//create passage between cell and neighbour
walker.CreatePassage(randomUnvisitedNeighbour);
randomUnvisitedNeighbour.CreatePassage(walker);
//the random unvisited neighbour is now the walker
walker = randomUnvisitedNeighbour;
}
else
{
//scan the grid for a hunted cell that is unvisited but has visited neighbours and mark it as visited
MazeCell huntedCell = GetRandomUnVisitedCellWithVisitedNeighbours(service);
huntedCell.MarkAsVisited();
visited.Add(huntedCell);
//fetch one of its visited neighbours and link it with the hunted cell
List <MazeCell> visitedNeighbours = service.GetVisitedNeighbours(huntedCell);
MazeCell randomVisitedNeighbour = visitedNeighbours[Random.Range(0, visitedNeighbours.Count)];
huntedCell.CreatePassage(randomVisitedNeighbour);
randomVisitedNeighbour.CreatePassage(huntedCell);
//the hunted cell is now the walker
walker = huntedCell;
}
walker.ShowAsStep(true);
yield return(null);
walker.ShowAsStep(false);
}
CompletedRoutine();
}
/// <summary>
/// Returns an enumerator that creates a maze by linking cells using the recursive backtracking algorithm
/// </summary>
/// <param name="service"></param>
/// <returns></returns>
public override IEnumerator CreateMazeRoutine(MazeGenerationService service)
{
//create data structures necessary for algorithm to work
Stack <MazeCell> stack = new Stack <MazeCell>();
List <MazeCell> visited = new List <MazeCell>();
//set starting point
MazeCell startCell = service.RootCell;
startCell.MarkAsVisited();
visited.Add(startCell);
stack.Push(startCell);
//loop until all cells have been visited
long totalCells = service.Cells.LongLength;
while (visited.Count != totalCells)
{
//pick the cell to branch from, from the top of the stack and retreive its neighbours
MazeCell newest = stack.Peek();
List <MazeCell> neighbours = service.GetUnVisitedNeighbours(newest);
if (neighbours.Count > 0)
{
//pick a random neighbour from the list
MazeCell neighbour = neighbours[Random.Range(0, neighbours.Count)];
//set it as visited and add it to the visited list
neighbour.MarkAsVisited();
visited.Add(neighbour);
//create passage between newest and neighbour
newest.CreatePassage(neighbour);
neighbour.CreatePassage(newest);
//push the neighbour to the stack
stack.Push(neighbour);
}
else
{
//if no unvisited neighbours are available, backtrack by popping the stack
stack.Pop();
}
newest.ShowAsStep(true);
yield return(null);
newest.ShowAsStep(false);
}
CompletedRoutine();
}
/// <summary>
/// Returns an Enumerator that creates a maze by linking cells using the growing tree algorithm its prim version
/// </summary>
/// <param name="service"></param>
public override IEnumerator CreateMazeRoutine(MazeGenerationService service)
{
//create data structures necessary for algorithm to work
List <MazeCell> bag = new List <MazeCell>();
List <MazeCell> visited = new List <MazeCell>();
//set starting point
MazeCell startPoint = service.RootCell;
startPoint.MarkAsVisited();
visited.Add(startPoint);
bag.Add(startPoint);
//loop until all cells have been visited
long totalCells = service.Cells.LongLength;
while (visited.Count != totalCells)
{
//pick a random cell from the bag and check if it has unvisited neighbours
MazeCell randomCell = bag[Random.Range(0, bag.Count)];
List <MazeCell> unvisitedNeighbours = service.GetUnVisitedNeighbours(randomCell);
if (unvisitedNeighbours.Count > 0)
{
//pick a random unvisited neighbour and mark it as visited
MazeCell randomUnvisitedNeighbour = unvisitedNeighbours[Random.Range(0, unvisitedNeighbours.Count)];
randomUnvisitedNeighbour.MarkAsVisited();
visited.Add(randomUnvisitedNeighbour);
//create passage between cell and neighbour
randomCell.CreatePassage(randomUnvisitedNeighbour);
randomUnvisitedNeighbour.CreatePassage(randomCell);
//add the random unvisited neighbour to the bag
bag.Add(randomUnvisitedNeighbour);
}
else
{
//if the cell doesn't have any unvisited neighbours, remove it from the bag
bag.Remove(randomCell);
}
randomCell.ShowAsStep(true);
yield return(null);
randomCell.ShowAsStep(false);
}
CompletedRoutine();
}
/// <summary>
/// Returns an enumerator that creates a maze by linking cells using prim's algorithm
/// </summary>
/// <param name="service"></param>
/// <returns></returns>
public override IEnumerator CreateMazeRoutine(MazeGenerationService service)
{
//create data structures necessary for algorithm to work
MazeCell[] cells = service.Cells.Cast <MazeCell>().ToArray();
List <MazeCell> frontier = new List <MazeCell>();
//set starting point
MazeCell startCell = service.RootCell;
startCell.MarkAsVisited();
//add neighbours of starting cell to frontier
frontier.AddRange(service.GetNeighbours(startCell));
while (frontier.Count != 0)
{
//pick a random frontier cell, mark it as visited and remove it from the frontier
MazeCell randomFrontierCell = frontier[Random.Range(0, frontier.Count)];
randomFrontierCell.MarkAsVisited();
frontier.Remove(randomFrontierCell);
//pick a random visited neighbour of it and link it with it
List <MazeCell> visitedNeighbours = service.GetVisitedNeighbours(randomFrontierCell);
if (visitedNeighbours.Count > 0)
{
MazeCell randomVisitedNeighbour = visitedNeighbours[Random.Range(0, visitedNeighbours.Count)];
randomFrontierCell.CreatePassage(randomVisitedNeighbour);
randomVisitedNeighbour.CreatePassage(randomFrontierCell);
}
//add unvisited neighbours of it to the frontier if they aren't already in it
List <MazeCell> unvisitedNeighbours = service.GetUnVisitedNeighbours(randomFrontierCell);
foreach (MazeCell cell in unvisitedNeighbours)
{
if (!frontier.Contains(cell))
{
frontier.Add(cell);
}
}
randomFrontierCell.ShowAsStep(true);
yield return(null);
randomFrontierCell.ShowAsStep(false);
}
CompletedRoutine();
}
