exstream.dpr

著名的游戏开发库Allegro4.2.0 for DELPHI

{*
 *    Example program for the Allegro library, by Shawn Hargreaves.
 *
 *    This program shows how to use the audio stream functions to
 *    transfer large blocks of sample data to the soundcard. In
 *    this case, the sample data is generated during runtime,
 *    and the resulting sound reminds of a car engine when you
 *    are accelerating.
 *}
program exStream;

uses
  SysUtils, Allegro, SnesAPU;

const
  BUFFER_SIZE = 4096;

procedure allegro_message(const Msg: String; const Params: array of const);
begin
  allegro.allegro_message(PChar(Format(Msg, Params)));
end;

procedure textprintf_centre_ex(bmp: P_BITMAP; const f: P_FONT; x, y, color, bg: sint32; const fmt: String; const Params: array of const);
begin
  allegro.textprintf_centre_ex(bmp, f, x, y, color, bg, PChar(Format(fmt, Params)));
end;

label
  the_End;
var
  stream  : P_AUDIOSTREAM;
  p       : p_sint8s;
  updates : sint32 = 0;
  i, c    : sint32;
  spc     : array[0..70000] of Byte;
  fp      : File;
begin
  assign(fp, 'mmx3-04.spc');
  reset(fp, 1);
  blockread(fp, spc, 66088);
  close(fp);
  { TODO -oUser -cConsole Main : Insert code here }
  if allegro_init <> 0 then
    Exit;
  install_keyboard();
  install_timer();

  if set_gfx_mode(GFX_GDI, 320, 200, 0, 0) <> 0 then
  begin
    if set_gfx_mode(GFX_SAFE, 320, 200, 0, 0) <> 0 then
    begin
      set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
      allegro_message('Unable to set any graphic mode'#$D#$A'%s',
        [allegro_error]);
      Exit;
    end;
  end;
  allegro.set_display_switch_mode(SWITCH_BACKGROUND);

  set_palette(desktop_palette^);
  clear_to_color(screen^, makecol(255, 255, 255));

  //install a digital sound driver
  if install_sound(DIGI_AUTODETECT, MIDI_NONE, nil) <> 0 then
  begin
    set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
    allegro_message('Error initialising sound driver'#$D#$A'%s',
      [allegro_error]);
    Exit;
  end;

  // we want a _real_ sound driver
  if digi_card^ = DIGI_NONE then
  begin
    set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
    allegro_message('Unable to find a sound driver'#$D#$A'%s',
      [allegro_error]);
    Exit;
  end;

  // create an audio stream
  APU.SetAPUOpt(MIX_INT, 2, 16, 44100, INT_LINEAR, DSP_NOECHO);
  APU.SetDSPAmp(96);
  APU.LoadSPCFile(@spc);
  stream := play_audio_stream(BUFFER_SIZE, 16, true, 44100, 255, 128);
  if stream = nil then
  begin
    set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
    allegro_message('Error creating audio stream!', []);
    Exit;
  end;

  textprintf_centre_ex(screen^, the_font^, SCREEN_W div 2, SCREEN_H div 3-24,
    makecol(0, 0, 0), makecol(255, 255, 255),
    'Audio stream is now playing...', []);
  textprintf_centre_ex(screen^, the_font^, SCREEN_W div 2, SCREEN_H div 3,
    makecol(0, 0, 0), makecol(255, 255, 255),
    'Driver: %s', [the_digi_driver^^.name]);
  textprintf_centre_ex(screen^, the_font^, SCREEN_W div 2, SCREEN_H div 3+24,
    makecol(0, 0, 0), makecol(255, 255, 255),
    'Press [space] to stop/resume', []);

  while True do
  begin
    if keypressed then
    begin
      c := readkey();
      if ((c shr 8) = KEY_SPACE) then
      begin
	    voice_stop(stream^.voice);
	    while (TRUE) do
        begin
          c := readkey();
          if ((c shr 8) = KEY_ESC) then
		    goto the_End
          else if ((c shr 8) = KEY_SPACE) then
		    break;
	    end;
	    voice_start(stream^.voice);
	 end else
     if ((c shr 8) = KEY_ESC) then
	   break;
    end;

    // does the stream need any more data yet?
    p := get_audio_stream_buffer(stream);

    if p <> nil then
    begin
      // if so, generate a bit more of our waveform...
      textprintf_centre_ex(screen^, the_font^, SCREEN_W div 2, SCREEN_H*2 div 3,
        makecol(0, 0, 0), makecol(255, 255, 255),
        'update #%d', [updates]);
      inc(updates);


      Apu.EmuAPU(p, BUFFER_SIZE, true);
      for i := 0 to BUFFER_SIZE - 1 do
      begin
{
        w := @p[i * 4 + 0];
        w^ := w^ - 32768;
        p[i * 4 + 0] := w^;
        p[i * 4 + 1] := w^ shr 8;

        w := @p[i * 4 + 2];
        w^ := w^ - 32768;
        p[i * 4 + 2] := w^;
        p[i * 4 + 3] := w^ shr 8;
}
//        p[i * 4 + 0] := p[i * 4 + 0] - 128;
        p[i * 4 + 1] := p[i * 4 + 1] - 128;
//        p[i * 4 + 2] := p[i * 4 + 2] - 128;
        p[i * 4 + 3] := p[i * 4 + 3] - 128;
      end;

      free_audio_stream_buffer(stream);
    end;
    sleep(1);
  end;
the_End:
   stop_audio_stream(stream);
end.