content: Function Main()
      print "starting alpha test"
      s=CreateObject("roScreen", true, 1280, 720)
      ' Clear to White with alpha fully opaque
      ' but alpha not actually ever used since it is the bottom most plane
      ' alpha is only looked at on "source" planes, not "destination".
      s.Clear(&hFFFFFFFF)
      ' AlphaEnable must be enabled in the destination surface to have effect.
      s.SetAlphaEnable(true)
      bm=CreateObject("roBitmap", {width:450, height: 450, alphaenable: true} )
      bm.Clear(&h0000FF01) 'blue, transparent with alpha = 0x01 otherwise it becomes black
      bm.drawRect(20,20,75,50,&hFF0000FF)
      bm.drawRect(50,50,75,50,&h0000FF78)
      bm.drawRect(80,80,75,50,&h00FF0078)
      s.DrawObject(0, 300, bm)
      b2=CreateObject("roBitmap", {width:450, height: 450, alphaenable: true} )
      b2.Clear(127)
      s.DrawObject(451, 0, b2)
      s.swapBuffers()
      ' redraw with the alpha disabled
      Sleep(10000)
      s.Clear(&hFFFFFFFF)
      s.SetAlphaEnable(false)
      s.DrawObject(0, 300, bm)
      s.DrawObject(451, 0, b2)
      s.swapBuffers()
      Sleep(10000)
  End Function