Monkey-X - Maze - Aldous-Broder - code example

#rem
Aldous-Broder Maze

From the book - Mazes for programmers -

#end

Import mojo

Class cell
    Field north:Bool,east:Bool
    Field south:Bool,west:Bool
    Field visited:Bool
End Class

Class aldousbrodermaze
    Field width:Int,height:Int
    Field tilewidth:Float,tileheight:Float
    Field map:cell[][]
    Method New(mazewidth:Int,mazeheight:Int,sw:Int,sh:Int)
        Self.width = mazewidth
        Self.height = mazeheight
        map = New cell[width][]
        For Local i=0 Until width
            map[i] = New cell[height]
        Next
        For Local y=0 Until height
        For Local x=0 Until width
            map[x][y] = New cell
        Next
        Next
        tilewidth = Float(sw)/Float(mazewidth)
        tileheight = Float(sh)/Float(mazeheight)
        makealdrousbrodermaze
    End Method
    '
    ' This method creates the maze
    ' This is like the drunken walk algorithm.
    ' You start a a random position And go in a
    ' random diagonal direction. If the New cell
    ' is unvisited Then carve a path And mark
    ' visited. If not visited Then keep moving around
    ' (no carving) until a unvisited cell is encountered.
    '
    Method makealdrousbrodermaze()
        Local remaining:Int=width*height-1
        Local mx:Int[] = [0,1,0,-1]
        Local my:Int[] = [-1,0,1,0]
        Local x:Int=Rnd(0,width)
        Local y:Int=Rnd(0,height)
        Local nx:Int,ny:Int
        map[x][y].visited = True
        While remaining>0        
            ' random direction 0up 1right 2down 3left
            Local dir:Int=Rnd(0,4)
            ' create new position
            nx = x+mx[dir]
            ny = y+my[dir]
            ' if in bounds
            If nx>=0 And ny>=0 And nx<width And ny<height
            ' if unvisited
            If map[nx][ny].visited = False
                ' mark visited
                map[nx][ny].visited = True
                ' exit loop counter -1
                remaining-=1
                ' carve into direction
                Select dir
                    Case 0'up
                    map[x][y].north = True
                    map[nx][ny].south = True
                    Case 1'right
                    map[x][y].east = True
                    map[nx][ny].west = True
                    Case 2'down
                    map[x][y].south = True
                    map[nx][ny].north = True
                    Case 3'left
                    map[x][y].west = True
                    map[nx][ny].east = True
                End Select
            End If
            ' set new position as current position
            x=nx
            y=ny
            End If
        Wend
    End Method
    '
    ' Draw the maze
    '
    Method draw()
        For Local y=0 Until height
        For Local x=0 Until width
            Local x1:Int=x*tilewidth
            Local y1:Int=y*tileheight
            SetColor 255,255,255
            If map[x][y].north = False
                DrawLine x1,y1,x1+tilewidth,y1
            End If
            If map[x][y].east = False
                DrawLine x1+tilewidth,y1,x1+tilewidth,y1+tileheight
            End If
            If map[x][y].south = False
                DrawLine x1,y1+tileheight,x1+tilewidth,y1+tileheight
            End If
            If map[x][y].west = False
                DrawLine x1,y1,x1,y1+tileheight
            End If
        Next
        Next
    End Method
End Class

Global maze:aldousbrodermaze

Class MyGame Extends App
    Method OnCreate()
        SetUpdateRate(1)
        maze = New aldousbrodermaze(10,10,500,400)
    End Method
    Method OnUpdate()        
        If MouseHit(MOUSE_LEFT)
            maze = New aldousbrodermaze(10,10,500,400)
        End If
    End Method
    Method OnRender()
        Cls 0,0,0 
        SetColor 255,255,255
        maze.draw
        DrawText "Aldous Broder Maze",0,480-40
        DrawText "Press Mouse or Touch to create new maze",0,480-20
    End Method
End Class


Function Main()
    New MyGame()
End Function