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unit UAudioPlayback_SDL;
interface
{$IFDEF FPC}
{$MODE Delphi}
{$ENDIF}
{$I switches.inc}
uses
Classes,
SysUtils,
UMusic;
implementation
uses
sdl,
UAudioPlayback_SoftMixer,
ULog,
UIni,
UMain;
type
TAudioPlayback_SDL = class(TAudioPlayback_SoftMixer)
private
function EnumDevices(): boolean;
protected
function InitializeAudioPlaybackEngine(): boolean; override;
function StartAudioPlaybackEngine(): boolean; override;
procedure StopAudioPlaybackEngine(); override;
function FinalizeAudioPlaybackEngine(): boolean; override;
public
function GetName: String; override;
procedure MixBuffers(dst, src: PChar; size: Cardinal; volume: Single); override;
end;
var
singleton_AudioPlaybackSDL : IAudioPlayback;
{ TAudioPlayback_SDL }
procedure SDLAudioCallback(userdata: Pointer; stream: PChar; len: integer); cdecl;
var
engine: TAudioPlayback_SDL;
begin
engine := TAudioPlayback_SDL(userdata);
engine.AudioCallback(stream, len);
end;
function TAudioPlayback_SDL.GetName: String;
begin
result := 'SDL_Playback';
end;
function TAudioPlayback_SDL.EnumDevices(): boolean;
begin
// Note: SDL does not provide Device-Selection capabilities (will be introduced in 1.3)
ClearOutputDeviceList();
SetLength(OutputDeviceList, 1);
OutputDeviceList[0] := TAudioOutputDevice.Create();
OutputDeviceList[0].Name := '[SDL Default-Device]';
Result := true;
end;
function TAudioPlayback_SDL.InitializeAudioPlaybackEngine(): boolean;
var
desiredAudioSpec, obtainedAudioSpec: TSDL_AudioSpec;
SampleBufferSize: integer;
begin
result := false;
EnumDevices();
if (SDL_InitSubSystem(SDL_INIT_AUDIO) = -1) then
begin
Log.LogError('SDL_InitSubSystem failed!', 'TAudioPlayback_SDL.InitializeAudioPlaybackEngine');
exit;
end;
SampleBufferSize := IAudioOutputBufferSizeVals[Ini.AudioOutputBufferSizeIndex];
if (SampleBufferSize <= 0) then
begin
// Automatic setting defaults to 1024 samples
SampleBufferSize := 1024;
end;
FillChar(desiredAudioSpec, sizeof(desiredAudioSpec), 0);
with desiredAudioSpec do
begin
freq := 44100;
format := AUDIO_S16SYS;
channels := 2;
samples := SampleBufferSize;
callback := @SDLAudioCallback;
userdata := Self;
end;
if(SDL_OpenAudio(@desiredAudioSpec, @obtainedAudioSpec) = -1) then
begin
Log.LogStatus('SDL_OpenAudio: ' + SDL_GetError(), 'TAudioPlayback_SDL.InitializeAudioPlaybackEngine');
exit;
end;
FormatInfo := TAudioFormatInfo.Create(
obtainedAudioSpec.channels,
obtainedAudioSpec.freq,
asfS16
);
Log.LogStatus('Opened audio device', 'TAudioPlayback_SDL.InitializeAudioPlaybackEngine');
result := true;
end;
function TAudioPlayback_SDL.StartAudioPlaybackEngine(): boolean;
begin
SDL_PauseAudio(0);
result := true;
end;
procedure TAudioPlayback_SDL.StopAudioPlaybackEngine();
begin
SDL_PauseAudio(1);
end;
function TAudioPlayback_SDL.FinalizeAudioPlaybackEngine(): boolean;
begin
SDL_CloseAudio();
SDL_QuitSubSystem(SDL_INIT_AUDIO);
Result := true;
end;
procedure TAudioPlayback_SDL.MixBuffers(dst, src: PChar; size: Cardinal; volume: Single);
begin
SDL_MixAudio(PUInt8(dst), PUInt8(src), size, Round(volume * SDL_MIX_MAXVOLUME));
end;
initialization
singleton_AudioPlaybackSDL := TAudioPlayback_SDL.create();
AudioManager.add( singleton_AudioPlaybackSDL );
finalization
AudioManager.Remove( singleton_AudioPlaybackSDL );
end.
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