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Rubygame::Music

IMPORTANT: this class only exists if SDL_mixer is available! Your code should check "defined?(Rubygame::Music) != nil" to see if you can use this class, or be prepared to rescue from NameError.

Music holds a song, streamed from an audio file (see load for supported formats). There are two important differences between the Music and Sound classes:

  1. Only one Music can be playing. If you try to play a second song, the first one will be stopped.

  2. Music doesn't load the entire audio file, so it can begin quickly and doesn't use much memory. This is good, because music files are usually much longer than sound effects!

Music can play, pause/unpause, stop, rewind, jump_to another time, adjust volume, and fade_out (fade in by passing an option to play).

Music includes the Rubygame::NamedResource mixin module, which can perform autoloading of music on demand, among other things.

Public Class Methods

autoload( filename ) click to toggle source

Searches each directory in Music.autoload_dirs for a file with the given filename. If it finds that file, loads it and returns a Music instance. If it doesn't find the file, returns nil.

See Rubygame::NamedResource for more information about this functionality.

# File lib/rubygame/music.rb, line 57
def autoload( filename )
  path = find_file( filename )

  if( path )
    return load( path )
  else
    return nil
  end
end
current_music() click to toggle source
# File lib/rubygame/music.rb, line 90
def current_music
  @current_music
end
load( filename ) click to toggle source

Load the given audio file. Supported file formats are WAVE, MOD, MIDI, OGG, and MP3.

filename

Full or relative path to the file. (String, required)

Returns

The new Music instance. (Music)

May raise

SDLError, if the music file could not be loaded.

# File lib/rubygame/music.rb, line 76
def load( filename )
  Rubygame.open_audio

  music = SDL::Mixer.LoadMUS( filename )

  if( music.pointer.null? )
    raise( Rubygame::SDLError, "Could not load Music file '%s': %s"%
           [filename, SDL.GetError()] )
  end

  return new( music )
end
new click to toggle source

*NOTE*: Don't use this method. Use Music.load.

Raises NotImplementedError.

# File lib/rubygame/music.rb, line 108
def initialize( music=nil )
  if( music.instance_of? SDL::Mixer::Music )
    @struct  = music
    @volume  = 1
    @repeats = 0
  else
    raise( NotImplementedError, "Music.new is not implemented. "+
           "Use Music.load to load a music file." )
  end
end

Public Instance Methods

fade_out( fade_time ) click to toggle source

Fade out to silence over the given number of seconds. Once the music is silent, it is automatically stopped.

Returns

The receiver (self).

*NOTE*: If the music is currently paused, the fade will start, but you won't be able to hear it happening unless you unpause during the fade.

Does nothing if the music is currently stopped.

# File lib/rubygame/music.rb, line 340
def fade_out( fade_time )
  if( fade_time < 0 )
    raise ArgumentError, "fade time cannot be negative (got %.2f)"%fade_time
  end

  if current?
    result = SDL::Mixer.FadeOutMusic( (fade_time * 1000).to_i )
    if( result < 0 )
      raise Rubygame::SDLError, "Error fading out music: #{SDL.GetError()}"
    end
  end

  return self
end
fading?( direction=:either ) click to toggle source

True if the Music is currently fading in or out. See also play and fade_out.

direction

Check if it is fading :in, :out, or :either. (Symbol, required)

# File lib/rubygame/music.rb, line 362
def fading?( direction=:either )
  return false unless current?

  case direction
  when :in
    SDL::Mixer.FadingMusic() == SDL::Mixer::FADING_IN
  when :out
    SDL::Mixer.FadingMusic() == SDL::Mixer::FADING_OUT
  else
    SDL::Mixer.FadingMusic() != SDL::Mixer::NO_FADING
  end
end
clone( other ) → music click to toggle source
dup( other ) → music

Create a copy of the given Music instance. More efficient than using load to load the music file again.

other

An existing Music instance. (Music, required)

Returns

The new Music instance. (Music)

*NOTE*: clone and dup do slightly different things; clone will copy the 'frozen' state of the object, while dup will create a fresh, un-frozen object.

# File lib/rubygame/music.rb, line 139
def initialize_copy( other )
  @struct  = other.struct
  @volume  = other.volume
  @repeats = other.repeats
end
jump_to( time ) click to toggle source

Jump to any time in the Music, in seconds since the beginning. If the Music was paused, it will still be paused again after the jump. Does nothing if the Music was stopped.

*NOTE*: Only works for OGG and MP3 formats! Other formats (e.g. WAV) will usually raise SDLError.

time

the time to jump to, in seconds since the beginning of the song. (Numeric, required)

May raise

SDLError if something goes wrong, or if the music type does not support jumping.

*CAUTION*: This method may be unreliable (and could even crash!) if you jump to a time after the end of the song. Unfortunately, SDL_Mixer does not provide a way to find the song's length, so Rubygame cannot warn you if you go off the end. Be careful!

# File lib/rubygame/music.rb, line 464
def jump_to( time )
  if current? and not stopped?
    was_paused = paused?

    if( time < 0 )
      raise Rubygame::SDLError, "cannot jump to negative time (got #{time})"
    end

    result = SDL::Mixer.SetMusicPosition( time.to_f )

    if( result == -1)
      raise Rubygame::SDLError, "could not jump music: #{SDL.GetError()}"
    end

    SDL::Mixer.PauseMusic() if was_paused
  end

  return self
end
pause() click to toggle source

Pause the Music. Unlike stop, it can be unpaused later to resume from where it was paused. See also unpause and paused?.

Returns

The receiver (self).

*NOTE*: Does nothing if the music is not currently playing.

# File lib/rubygame/music.rb, line 268
def pause
  if current?
    SDL::Mixer.PauseMusic()
  end

  return self
end
paused?() click to toggle source

True if the Music is currently paused (not playing and not stopped). See also playing? and stopped?.

# File lib/rubygame/music.rb, line 296
def paused?
  current? and
    SDL::Mixer.PlayingMusic() == 1 and
    SDL::Mixer.PausedMusic() == 1
end
play( options={:fade_in => 0, :repeats => 0, :start_at => 0} ) click to toggle source

Play the Music, optionally fading in, repeating a certain number of times (or forever), and/or starting at a certain position in the song.

See also pause and stop.

options

Hash of options, listed below. (Hash, required)

:fade_in

Fade in from silence over the given number of seconds. Default: 0. (Numeric, optional)

:repeats

Repeat the music the given number of times, or forever (or until stopped) if -1. Default: 0. (Integer, optional)

:start_at

Start playing the music at the given time in the song, in seconds. Default: 0. (Numeric, optional) *NOTE*: Non-zero start times only work for OGG and MP3 formats! Please refer to jump.

Returns

The receiver (self).

May raise

SDLError, if the audio device could not be opened, or if the music file could not be played, or if you used :start_at with an unsupported format.

*NOTE*: Only one music can be playing at once. If any music is already playing (or paused), it will be stopped before playing the new music.

Example:

# Fade in over 2 seconds, play 4 times (1 + 3 repeats),
# starting at 60 seconds since the beginning of the song.
music.play( :fade_in => 2, :repeats => 3, :start_at => 60 );
# File lib/rubygame/music.rb, line 184
def play( options={} )

  fade_in  = (options[:fade_in]  or 0)
  repeats  = (options[:repeats]  or 0)
  start_at = (options[:start_at] or 0)


  fade_in =
    if( fade_in < 0 )
      raise ArgumentError, ":fade_in cannot be negative (got %.2f)"%fade_in
    elsif( fade_in < 0.05 )
      # Work-around for a bug with SDL_mixer not working with small
      # non-zero fade-ins
      0
    else
      (fade_in * 1000).to_i
    end


  repeats =
    if( repeats < -1 )
      raise( ArgumentError,
             ":repeats cannot be negative, except -1 (got #{repeats})" )
    elsif( repeats > -1 )
      # Adjust so repeats means the same as it does for Sound
      (repeats + 1).to_i
    else
      -1
    end


  start_at =
    if( start_at < 0 )
      raise( ArgumentError,
             ":start_at cannot be negative, (got %.2f)"%start_at )
    else
      start_at.to_f
    end


  Rubygame.open_audio


  # Doing a little restart dance to please the SDL_mixer gods.
  SDL::Mixer.PlayMusic( @struct, 0 )
  SDL::Mixer.HaltMusic()

  # Set music channel volume before we play
  SDL::Mixer.VolumeMusic( (SDL::Mixer::MAX_VOLUME * @volume).to_i )


  @repeats = repeats

  result = SDL::Mixer.FadeInMusicPos( @struct, repeats, fade_in, start_at )

  if( result == -1 )
    raise Rubygame::SDLError, "Could not play Music: #{SDL.GetError()}"
  end

  self.class.__current_music = self

  return self

end
playing?() click to toggle source

True if the Music is currently playing (not paused and not stopped). See also paused? and stopped?.

# File lib/rubygame/music.rb, line 253
def playing?
  current? and
    SDL::Mixer.PlayingMusic() == 1 and
    SDL::Mixer.PausedMusic() == 0
end
rewind() click to toggle source

Rewind the Music to the beginning. If the Music was paused, it will still be paused after the rewind. Does nothing if the Music is stopped.

# File lib/rubygame/music.rb, line 428
def rewind
  if current? and not stopped?
    was_paused = paused?

    SDL::Mixer.HaltMusic()
    result = SDL::Mixer.PlayMusic(@struct, @repeats)

    if( result == -1 )
      raise Rubygame::SDLError, "Could not rewind music: #{SDL.GetError()}"
    end

    SDL::Mixer.PauseMusic() if was_paused
  end

  return self
end
stop() click to toggle source

Stop the Music. Unlike pause, the music must be played again from the beginning, it cannot be resumed from it was stopped.

Returns

The receiver (self).

*NOTE*: Does nothing if the music is not currently playing or paused.

# File lib/rubygame/music.rb, line 311
def stop
  if current?
    SDL::Mixer.HaltMusic()
  end

  return self
end
stopped?() click to toggle source

True if the Music is currently stopped (not playing and not paused). See also playing? and paused?.

# File lib/rubygame/music.rb, line 323
def stopped?
  (not current?) or (SDL::Mixer.PlayingMusic() == 0)
end
unpause() click to toggle source

Unpause the Music, if it is currently paused. Resumes from where it was paused. See also pause and paused?.

Returns

The receiver (self).

*NOTE*: Does nothing if the music is not currently paused.

# File lib/rubygame/music.rb, line 284
def unpause
  if current?
    SDL::Mixer.ResumeMusic()
  end

  return self
end
volume() click to toggle source

Return the volume level of the music. 0.0 is totally silent, 1.0 is full volume.

*NOTE*: Ignores fading in or out.

# File lib/rubygame/music.rb, line 382
def volume
  @volume
end
volume=( new_vol ) click to toggle source

Set the new volume level of the music. 0.0 is totally silent, 1.0 is full volume. The new volume will be clamped to this range if it is too small or too large.

Volume cannot be set while the music is fading in or out. Be sure to check fading? or rescue from SDLError when using this method.

May raise

SDLError if the music is fading in or out.

# File lib/rubygame/music.rb, line 398
def volume=( new_vol )
  # Clamp it to valid range
  new_vol = if new_vol < 0.0;      0.0
            elsif new_vol > 1.0;   1.0
            else;                  new_vol
            end

  if current?
    if fading?
      raise Rubygame::SDLError, "cannot set Music volume while fading"
    else
      SDL::Mixer.VolumeMusic( (SDL::Mixer::MAX_VOLUME * new_vol).to_i )
    end
  end

  @volume = new_vol
end

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