public Maze Build()
{
Maze maze = new Maze(mazeWidth, mazeHeight);
// Build a full spanning tree maze first
System.Random random = new System.Random();
ISet <CellPosition> visitedCells = new HashSet <CellPosition>();
List <WallPosition> walls = new List <WallPosition>();
CellPosition p = new CellPosition(random.Next() % mazeWidth, random.Next() % mazeHeight);
foreach (CellPosition neighbour in p.Neighbours())
{
if (!IsValidCellPosition(maze, neighbour))
{
continue;
}
walls.Add(new WallPosition(p, neighbour));
}
visitedCells.Add(p);
while (walls.Count > 0)
{
int wallIdx = random.Next() % walls.Count;
WallPosition wall = walls[wallIdx];
walls.RemoveAt(wallIdx);
if (visitedCells.Contains(wall.next))
{
continue;
}
if (wall.cell.x == wall.next.x)
{
maze.cells[wall.cell.x, Math.Min(wall.cell.y, wall.next.y)] |= Maze.Passage.Top;
}
else
{
maze.cells[Math.Min(wall.cell.x, wall.next.x), wall.cell.y] |= Maze.Passage.Right;
}
p = wall.next;
foreach (CellPosition neighbour in p.Neighbours())
{
if (!IsValidCellPosition(maze, neighbour))
{
continue;
}
walls.Add(new WallPosition(p, neighbour));
}
visitedCells.Add(p);
}
// Then reduce number of walls to wallCount
List <WallPosition> leftoverWalls = new List <WallPosition>();
for (int x = 0; x < maze.width; x++)
{
for (int y = 0; y < maze.height; y++)
{
if (x < maze.width - 1 && ((maze.cells[x, y] & Maze.Passage.Right) == Maze.Passage.None))
{
leftoverWalls.Add(new WallPosition(new CellPosition(x, y), new CellPosition(x + 1, y)));
}
if (y < maze.height - 1 && ((maze.cells[x, y] & Maze.Passage.Top) == Maze.Passage.None))
{
leftoverWalls.Add(new WallPosition(new CellPosition(x, y), new CellPosition(x, y + 1)));
}
}
}
while (leftoverWalls.Count > wallCount)
{
int wallIdx = random.Next() % leftoverWalls.Count;
WallPosition wall = leftoverWalls[wallIdx];
if (wall.cell.x == wall.next.x)
{
maze.cells[wall.cell.x, Math.Min(wall.cell.y, wall.next.y)] |= Maze.Passage.Top;
}
else
{
maze.cells[Math.Min(wall.cell.x, wall.next.x), wall.cell.y] |= Maze.Passage.Right;
}
leftoverWalls.RemoveAt(wallIdx);
}
return(maze);
}
