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

---

测试代码:

---

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.

---

窗体设计:

---

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

---

运行效果图:

---