在 Delphi 下使用 DirectSound (13): 测试回声效果器 IDirectSoundFXEcho8

{相关结构:}

TDSFXEcho = packed record

  fWetDryMix: Single;  //0 .. 100  : 50 (%)

  fFeedback: Single;   //0 .. 100  : 50 (%)

  fLeftDelay: Single;  //1 .. 2000 : 500(ms)

  fRightDelay: Single; //1 .. 2000 : 500(ms)

  lPanDelay: Longint;  //0 .. 1    : 0  (False)

end;



//该结构相关常量:

DSFXECHO_WETDRYMIX_MIN  = 0.0;

DSFXECHO_WETDRYMIX_MAX  = 100.0;



DSFXECHO_FEEDBACK_MIN   = 0.0;

DSFXECHO_FEEDBACK_MAX   = 100.0;



DSFXECHO_LEFTDELAY_MIN  = 1.0;

DSFXECHO_LEFTDELAY_MAX  = 2000.0;



DSFXECHO_RIGHTDELAY_MIN = 1.0;

DSFXECHO_RIGHTDELAY_MAX = 2000.0;



DSFXECHO_PANDELAY_MIN   = 0; //False

DSFXECHO_PANDELAY_MAX   = 1; //True

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测试代码:

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unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls, ExtCtrls;



type

  TForm1 = class(TForm)

    Button1: TButton;

    Button2: TButton;

    LabeledEdit1: TLabeledEdit;

    LabeledEdit2: TLabeledEdit;

    LabeledEdit3: TLabeledEdit;

    LabeledEdit4: TLabeledEdit;

    RadioGroup1: TRadioGroup;

    procedure FormCreate(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure RadioGroup1Click(Sender: TObject);

    procedure LabeledEdit1Change(Sender: TObject);

    procedure FormDestroy(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses DirectSound, ReadWave2;



var

  myDSound: IDirectSound8;

  buf8: IDirectSoundBuffer8;

  fxEcho: IDirectSoundFXEcho8; //IDirectSoundFXEcho8 效果器



procedure TForm1.FormCreate(Sender: TObject);

begin

  System.ReportMemoryLeaksOnShutdown := True;

  DirectSoundCreate8(nil, myDSound, nil);

  myDSound.SetCooperativeLevel(Handle, DSSCL_NORMAL);



  Button1.Caption := '打开并播放';

  Button2.Caption := '停止播放';



  LabeledEdit1.EditLabel.Caption := 'fWetDryMix: 0.0 - 100.';

  LabeledEdit1.Text := '50.0';

  LabeledEdit1.Tag := 1;



  LabeledEdit2.EditLabel.Caption := 'fFeedback: 0.0 - 100.0';

  LabeledEdit2.Text := '50.0';

  LabeledEdit2.Tag := 2;



  LabeledEdit3.EditLabel.Caption := 'fLeftDelay: 1.0 - 2000.0';

  LabeledEdit3.Text := '500.0';

  LabeledEdit3.Tag := 3;



  LabeledEdit4.EditLabel.Caption := 'fRightDelay: 1.0 - 2000.0';

  LabeledEdit4.Text := '500.0';

  LabeledEdit4.Tag := 4;



  RadioGroup1.Caption := 'lPanDelay:';

  RadioGroup1.Items.CommaText := 'False, True';

  RadioGroup1.ItemIndex := 0;



  LabeledEdit2.OnChange := LabeledEdit1.OnChange;

  LabeledEdit3.OnChange := LabeledEdit1.OnChange;

  LabeledEdit4.OnChange := LabeledEdit1.OnChange;

end;

procedure TForm1.Button1Click(Sender: TObject);

var

  buf: IDirectSoundBuffer;

  bufDesc: TDSBufferDesc;

  rEffect: TDSEffectDesc;

  wav: TReadWave;

  p1: Pointer;

  n1: DWORD;

begin

  wav := TReadWave.Create;

  if not wav.OpenDialog then begin wav.Free; Exit; end;



  ZeroMemory(@bufDesc, SizeOf(TDSBufferDesc));

  bufDesc.dwSize := SizeOf(TDSBufferDesc);

  bufDesc.dwFlags := DSBCAPS_CTRLFX;

  bufDesc.dwBufferBytes := wav.Size;

  bufDesc.lpwfxFormat := @wav.Format;

  myDSound.CreateSoundBuffer(bufDesc, buf, nil);

  buf.QueryInterface(IID_IDirectSoundBuffer8, buf8);



  buf8.Lock(0, 0, @p1, @n1, nil, nil, DSBLOCK_ENTIREBUFFER);

  wav.Read(p1, n1);

  wav.Free;

  buf8.Unlock(p1, n1, nil, 0);



  ZeroMemory(@rEffect, SizeOf(TDSEffectDesc));

  rEffect.dwSize := SizeOf(TDSEffectDesc);

  rEffect.dwFlags := 0;

  rEffect.guidDSFXClass := GUID_DSFX_STANDARD_ECHO;

  buf8.SetFX(1, @rEffect, nil);

  buf8.GetObjectInPath(GUID_DSFX_STANDARD_ECHO, 0, IID_IDirectSoundFXEcho8, fxEcho);

  buf8.Play(0, 0, DSBPLAY_LOOPING);

end;



procedure TForm1.Button2Click(Sender: TObject);

begin

  if Assigned(buf8) then buf8.Stop;

end;



procedure TForm1.RadioGroup1Click(Sender: TObject);

var

  rEcho: TDSFXEcho;

begin

  if buf8 = nil then Exit;

  rEcho.fWetDryMix := StrToFloat(LabeledEdit1.Text);

  rEcho.fFeedback     := StrToFloat(LabeledEdit2.Text);

  rEcho.fLeftDelay  := StrToFloat(LabeledEdit3.Text);

  rEcho.fRightDelay := StrToFloat(LabeledEdit4.Text);

  rEcho.lPanDelay  := RadioGroup1.ItemIndex;

  fxEcho.SetAllParameters(rEcho);

end;



procedure TForm1.LabeledEdit1Change(Sender: TObject);

var

  f: Single;

  obj: TLabeledEdit;

begin

  obj := Sender as TLabeledEdit;

  //if obj.Text = '-' then Exit;

  f := StrToFloatDef(obj.Text, MaxInt);

  case obj.Tag of

    1:   if (f < 0) or (f > 100)  then obj.Text := '50.0';

    2:   if (f < 0) or (f > 100)  then obj.Text := '50.0';

    3,4: if (f < 1) or (f > 2000) then obj.Text := '500.0';

  end;

  RadioGroup1.OnClick(nil);

end;



procedure TForm1.FormDestroy(Sender: TObject);

begin

  buf8 := nil;

  myDSound := nil;

end;



end.

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窗体设计:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 194

  ClientWidth = 326

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  OnCreate = FormCreate

  OnDestroy = FormDestroy

  PixelsPerInch = 96

  TextHeight = 13

  object Button1: TButton

    Left = 32

    Top = 22

    Width = 75

    Height = 25

    Caption = 'Button1'

    TabOrder = 0

    OnClick = Button1Click

  end

  object Button2: TButton

    Left = 32

    Top = 53

    Width = 75

    Height = 25

    Caption = 'Button2'

    TabOrder = 1

    OnClick = Button2Click

  end

  object LabeledEdit1: TLabeledEdit

    Left = 168

    Top = 24

    Width = 138

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit1'

    TabOrder = 2

    OnChange = LabeledEdit1Change

  end

  object LabeledEdit2: TLabeledEdit

    Left = 168

    Top = 67

    Width = 138

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit2'

    TabOrder = 3

  end

  object LabeledEdit3: TLabeledEdit

    Left = 168

    Top = 112

    Width = 138

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit3'

    TabOrder = 4

  end

  object LabeledEdit4: TLabeledEdit

    Left = 168

    Top = 160

    Width = 138

    Height = 21

    EditLabel.Width = 61

    EditLabel.Height = 13

    EditLabel.Caption = 'LabeledEdit4'

    TabOrder = 5

  end

  object RadioGroup1: TRadioGroup

    Left = 16

    Top = 104

    Width = 129

    Height = 77

    Caption = 'RadioGroup1'

    TabOrder = 6

    OnClick = RadioGroup1Click

  end

end

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运行效果图:

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