Graphics 800,600,0,2
SetBuffer BackBuffer()
SeedRnd MilliSecs()

Const Points = 6

Dim Point#(Points,2)
RandomizeFigure()

While Not KeyDown(1)
 Cls
 If KeyHit(57) Then RandomizeFigure()
 ShowFigure()
 Text 1,1,\"MOUSEOVER: \" + MouseOver(MouseX(),MouseY())
 Flip
Wend
End

Function RandomizeFigure()
 For i = 0 To Points-1
  Point(i,1) = Rand(GraphicsWidth())
  Point(i,2) = Rand(GraphicsHeight())
 Next
End Function

Function ShowFigure()
 Color 255,255,255
 For i = 0 To Points-1
  Line Point(i,1), Point(i,2), Point((i+1) Mod Points,1), Point((i+1) Mod Points,2)
 Next
End Function

Function MouseOver(x#,y#)
 Color 100,100,100
 Line x,0,x,600
 For i = 0 To Points-1
  x1# = Point(i,1)
  x2# = Point((i+1) Mod Points, 1)
  y1# = Point(i,2)
  y2# = Point((i+1) Mod Points, 2)
  If x2 < x1 Then x3 = x2  x2 = x1  x1 = x3  y3 = y2  y2 = y1  y1 = y3
  If (x >= x1) And (x <= x2) Then
   yp# = y1 + (x - x1) * (y2 - y1) / (x2 - x1)
   If yp <= y Then s = s + 1
   Color 255,0,0
   Oval x-3,yp-3,6,6,1
  EndIf
 Next
 Color 255,255,255
 Return s Mod 2
End Function