; ChannelPitch Example
; --------------------

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

; A short tone looped endlessly gives us a steady engine hum
snd=LoadSound("media/beep.wav")
LoopSound snd
channel=PlaySound(snd)

; beep.wav was recorded at 11025 hertz - its natural pitch
hertz=11025

While Not KeyDown(1)

    ; Hold Up/Down to rev the engine like a siren
    If KeyDown(200) And hertz<33000 Then hertz=hertz+150
    If KeyDown(208) And hertz>2000 Then hertz=hertz-150

    ; ChannelPitch retunes the channel WHILE it plays - no need to
    ; restart it. (SoundPitch instead changes the sound for future
    ; PlaySound calls.)
    ChannelPitch channel,hertz

    Cls

    ; A frequency meter: the bar grows with the hertz value
    Color 100,100,100
    Rect 100,240,441,20,False
    Color 255,180,80
    Rect 102,242,(hertz-2000)*437/31000,16

    Color 255,255,255
    Text 0,0,"Up/Down: rev the live channel   Esc: exit"
    Text 0,20,"ChannelPitch channel,"+hertz+"   (recorded at 11025 Hz)"

    Flip

Wend

StopChannel channel

End