Class Rubygame::Music
In: lib/rubygame/music.rb
Parent: Object

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.

Methods

autoload   current_music   fade_out   fading?   initialize_copy   jump_to   load   new   pause   paused?   play   playing?   rewind   stop   stopped?   unpause   volume   volume=  

Included Modules

Rubygame::NamedResource

Public Class methods

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.

[Source]

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

      if( path )
        return load( path )
      else
        return nil
      end
    end

[Source]

# File lib/rubygame/music.rb, line 90
    def current_music
      @current_music
    end

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.

[Source]

# 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

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

Raises NotImplementedError.

[Source]

# 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 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.

[Source]

# 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

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)

[Source]

# 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

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.

[Source]

# File lib/rubygame/music.rb, line 139
  def initialize_copy( other )
    @struct  = other.struct
    @volume  = other.volume
    @repeats = other.repeats
  end

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!

[Source]

# 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 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.

[Source]

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

    return self
  end

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

[Source]

# File lib/rubygame/music.rb, line 296
  def paused?
    current? and
      SDL::Mixer.PlayingMusic() == 1 and
      SDL::Mixer.PausedMusic() == 1
  end

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 );

[Source]

# 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

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

[Source]

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

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.

[Source]

# 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 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.

[Source]

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

    return self
  end

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

[Source]

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

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.

[Source]

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

    return self
  end

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

*NOTE*: Ignores fading in or out.

[Source]

# File lib/rubygame/music.rb, line 382
  def volume
    @volume
  end

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.

[Source]

# 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

[Validate]