Как сделать регулятор громкости?

Code:

uses MMSystem;

procedure TForm1.Button1Click(Sender: TObject);

var

vol: longint;

LVol, RVol: integer;

begin

AuxGetVolume(ListBox1.ItemIndex, @Vol);

LVol := Vol shr 16;

if LVol < MaxWord - 1000

   then LVol := LVol + 1000

   else LVol := MaxWord;

RVol := (Vol shl 16) shr 16;

if RVol < MaxWord - 1000

   then RVol := RVol + 1000

   else RVol := MaxWord;

AuxSetVolume(ListBox1.ItemIndex, LVol shl 16 + RVol);

end;

procedure TForm1.FormCreate(Sender: TObject);

var

i: integer;

cap: TAuxCaps;

begin

for i := 0 to auxGetNumDevs - 1 do begin

   auxGetDevCaps(i, Addr(cap), SizeOf(cap));

   ListBox1.Items.Add(cap.szPname)

end;

end;

Code:

uses mmsystem;

function GetWaveVolume: DWord;

var

Woc : TWAVEOUTCAPS;

Volume : DWord;

begin

result:=0;

if WaveOutGetDevCaps(WAVE_MAPPER, @Woc, sizeof(Woc)) = MMSYSERR_NOERROR then

if Woc.dwSupport and WAVECAPS_VOLUME = WAVECAPS_VOLUME then

begin

WaveOutGetVolume(WAVE_MAPPER, @Volume);

Result := Volume;

end;

end;

procedure SetWaveVolume(const AVolume: DWord);

var Woc : TWAVEOUTCAPS;

begin

if WaveOutGetDevCaps(WAVE_MAPPER, @Woc, sizeof(Woc)) = MMSYSERR_NOERROR then

if Woc.dwSupport and WAVECAPS_VOLUME = WAVECAPS_VOLUME then WaveOutSetVolume(WAVE_MAPPER, AVolume);

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

Beep;

end;

procedure TForm1.Button2Click(Sender: TObject);

var

LeftVolume: Word;

RightVolume: Word;

begin

LeftVolume := StrToInt(Edit1.Text);

RightVolume := StrToInt(Edit2.Text);

SetWaveVolume(MakeLong(LeftVolume, RightVolume));

end;

procedure TForm1.Button3Click(Sender: TObject);

begin

Caption := IntToStr(GetWaveVolume);

end;