; FlushKeys Example
; -----------------

Graphics 640,480,0,2
SetBuffer BackBuffer()

; Keypresses queue up in a buffer until your program reads them.
; FlushKeys empties that queue - call it before a "press a key"
; prompt so an old, stale keypress cannot skip it.

flush_mode=1
quit=0

Repeat

    ; Start each round with an empty queue
    FlushKeys

    ; Phase 1: let keypresses pile up unread for three seconds
    finish=MilliSecs()+3000
    While MilliSecs()<finish
        If KeyDown(1) Then Exit
        Cls
        Text 0,0,"Mash some letter keys NOW - they are queuing up unread!"
        Text 0,20,"Time left: "+((finish-MilliSecs())/1000+1)
        If flush_mode Then
            Text 0,40,"FlushKeys WILL be called before the queue is read."
        Else
            Text 0,40,"FlushKeys will NOT be called - watch the queue survive."
        End If
        Flip
    Wend

    ; Phase 2: optionally flush, then read whatever survived
    used_flush=flush_mode
    If flush_mode Then FlushKeys ; the documented command - empties the buffer

    caught$=""
    k=GetKey()
    While k>0
        If k>=32 And k<=126 Then caught$=caught$+Chr$(k)
        k=GetKey()
    Wend

    ; Discard Space/F presses made while mashing so the menu below
    ; does not trigger instantly
    dummy=KeyHit(57)+KeyHit(33)

    ; Phase 3: show the result and offer another run
    done=0
    While done=0
        Cls
        Text 0,0,"Space: run again   F: toggle FlushKeys   Esc: exit"
        Text 0,40,"Keys read from the buffer: '"+caught$+"'"
        If used_flush Then
            Text 0,60,"FlushKeys was called first, so the queue came back empty."
        Else
            Text 0,60,"No flush - every buffered press was still waiting."
        End If
        If flush_mode Then
            Text 0,100,"Next run: FlushKeys ON"
        Else
            Text 0,100,"Next run: FlushKeys OFF"
        End If
        Flip
        If KeyHit(57) Then done=1
        If KeyHit(33) Then flush_mode=1-flush_mode
        If KeyDown(1) Then quit=1
        If quit Then done=1
    Wend

Until quit

End