Monkey-X - Midpoint Division Algorithm - code example

Import mojo

Global screenwidth:Int=640
Global screenheight:Int=480

Class midpoint
    Field mw:Int,mh:Int
    Field tw:Float,th:Float
    Field map:Int[][]
    Method New(w:Int,h:Int)
        mw = w
        mh = h
        tw = Float(screenwidth)/Float(mw)
        th = Float(screenheight)/Float(mh)
        map = New Int[w][]
        For Local i = 0 Until mw
            map[i] = New Int[mh]
        Next        
         map[0][0] = 128
          map[mw-1][0] = 128
          map[mw-1][mh-1] = 128
          map[0][mh-1] = 128
          midpoint(0,0,mw-1,mh-1)
    End Method
    Method midpoint(x1:Int,y1:Int,x2:Int,y2:Int)
           If(x2-x1<2 And y2-y1<2) Return False
            Local dist:Int=(x2-x1+y2-y1)
            Local hdist:Int=dist / 2
                Local midx:Int=(x1+x2) / 2
            Local midy:Int=(y1+y2) / 2
                Local c1:Int=map[x1][y1]
            Local c2:Int=map[x2][y1]
            Local c3:Int=map[x2][y2]
            Local c4:Int=map[x1][y2]
            If(map[midx][y1]=0) Then map[midx][y1]=((c1+c2+Rnd(dist)-hdist) / 2)
            If(map[midx][y2]=0) Then map[midx][y2]=((c4+c3+Rnd(dist)-hdist) / 2)
            If(map[x1][midy]=0) Then map[x1][midy]=((c1+c4+Rnd(dist)-hdist) / 2)
            If(map[x2][midy]=0) Then map[x2][midy]=((c2+c3+Rnd(dist)-hdist) / 2)
                
                map[midx][midy] = ((c1+c2+c3+c4+Rnd(dist)-hdist) / 4)
               midpoint(x1,y1,midx,midy)
            midpoint(midx,y1,x2,midy)
            midpoint(x1,midy,midx,y2)
            midpoint(midx,midy,x2,y2)

    End Method 
    Method draw()
        For Local y:Int=0 Until mh
        For Local x:Int=0 Until mw
            Local c:Int=map[x][y]
            SetColor c,c,c
            DrawRect x*tw,y*th,tw+1,th+1
        Next
        Next
    End Method
End Class

Global mymidpoint:midpoint

Class MyGame Extends App
    field cnt:Int=0
    Method OnCreate()
        SetUpdateRate(1)
        mymidpoint = New midpoint(256,256)
    End Method
    Method OnUpdate() 
        cnt+=1
        If cnt>2 Then
            mymidpoint = New midpoint(256,256)
            cnt=0
        End If           
    End Method
    Method OnRender()
        'Cls 0,0,0 
        mymidpoint.draw
        'SetColor 255,255,255
    End Method
End Class


Function Main()
    New MyGame()
End Function