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Rubygame::Sound

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

Sound holds a sound effect, loaded from an audio file (see load for supported formats).

Sound can play, pause/unpause, stop, adjust volume, and fade_out (you can fade in by passing an option to play).

Sound can create duplicates (with dup or clone) in a memory-efficient way -- the new Sound instance refers back to the same audio data, so having 100 duplicates of a sound uses only slightly more memory than having the first sound. Duplicates can different volume levels, too!

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

Public Class Methods

autoload( filename ) click to toggle source

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

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

# File lib/rubygame/sound.rb, line 54
def autoload( filename )
  path = find_file( filename )

  if( path )
    return load( path )
  else
    return nil
  end
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 Sound instance. (Sound)

May raise

SDLError, if the sound file could not be loaded.

# File lib/rubygame/sound.rb, line 73
def load( filename )
  Rubygame.open_audio

  sound = SDL::Mixer.LoadWAV( filename )

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

  return new( sound )
end
new click to toggle source

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

Raises NotImplementedError.

# File lib/rubygame/sound.rb, line 96
def initialize( sound=nil )
  if( sound.instance_of? SDL::Mixer::Chunk )
    @struct  = sound
    @volume  = 1
    @channel = -1
  else
    raise( NotImplementedError, "Sound.new is not implemented. "+
           "Use Sound.load to load a sound 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 sound is silent, it is automatically stopped.

Returns

The receiver (self).

*NOTE*: If the sound 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 sound is currently stopped.

# File lib/rubygame/sound.rb, line 346
def fade_out( fade_time )
  if( fade_time < 0 )
    raise ArgumentError, "fade time cannot be negative (got %.2f)"%fade_time
  end

  if channel_active?
    SDL::Mixer.FadeOutChannel( @channel, (fade_time * 1000).to_i )
  end

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

True if the Sound 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/sound.rb, line 365
def fading?( direction=:either )
  return false unless channel_active?

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

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

other

An existing Sound instance. (Sound, required)

Returns

The new Sound instance. (Sound)

*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/sound.rb, line 127
def initialize_copy( other )
  @struct  = other.struct
  @volume  = other.volume
  @channel = -1
end
pause() click to toggle source

Pause the Sound. 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 sound is not currently playing.

# File lib/rubygame/sound.rb, line 274
def pause
  if channel_active?
    SDL::Mixer.Pause( @channel )
  end

  return self
end
paused?() click to toggle source

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

# File lib/rubygame/sound.rb, line 302
def paused?
  channel_active? and
    SDL::Mixer.Playing( @channel ) == 1 and
    SDL::Mixer.Paused( @channel ) == 1
end
play( options={:fade_in => 0, :repeats => 0, :stop_after => nil} ) click to toggle source

Play the Sound, optionally fading in, repeating a certain number of times (or forever), and/or stopping automatically after a certain time.

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

:stop_after

Automatically stop playing after playing for the given number of seconds. Use nil to disable this behavior. (Numeric or nil, optional)

Returns

The receiver (self).

May raise

SDLError, if the audio device could not be opened, or if the sound file could not be played.

*NOTE*: If the sound is already playing (or paused), it will be stopped and played again from the beginning.

Example:

# Fade in over 2 seconds, play 4 times (1 + 3 repeats),
# but stop playing after 5 seconds.
sound.play( :fade_in => 2, :repeats => 3, :stop_after => 5 );
# File lib/rubygame/sound.rb, line 168
def play( options={} )

  fade_in    = (options[:fade_in]  or 0)
  repeats    = (options[:repeats]  or 0)
  stop_after = (options[:stop_after] or nil)


  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})" )
    else
      repeats
    end


  stop_after =
    if( stop_after.nil? )
      -1
    elsif( stop_after < 0 )
      raise( ArgumentError,
             ":stop_after cannot be negative, (got %.2f)"%stop_after )
    else
      (stop_after * 1000).to_i
    end



  Rubygame.open_audio


  # If it's already playing on a channel, stop it first.
  if channel_active?
    SDL::Mixer.HaltChannel( @channel )
  end


  # Find first available channel
  @channel = SDL::Mixer.GroupAvailable(-1)


  if @channel == -1
    # No channels were available, so make one more than there are now.
    # (Mix_AllocateChannels(-1) returns the current number of channels)
    SDL::Mixer.AllocateChannels( SDL::Mixer.AllocateChannels(-1) + 1 )

    # Try again
    @channel = SDL::Mixer.GroupAvailable(-1)
  end


  # Set sound channel volume before we play
  SDL::Mixer.Volume( @channel, (SDL::Mixer::MAX_VOLUME * @volume).to_i )


  result =
    if( fade_in <= 0 )
      # Play sound without fading in
      SDL::Mixer.PlayChannelTimed( @channel, @struct, repeats, stop_after )
    else
      # Play sound with fading in
      SDL::Mixer.FadeInChannelTimed( @channel, @struct,
                                     repeats, fade_in, stop_after )
    end


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


  return self

end
playing?() click to toggle source

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

# File lib/rubygame/sound.rb, line 259
def playing?
  channel_active? and
    SDL::Mixer.Playing(@channel) == 1 and
    SDL::Mixer.Paused(@channel) == 0
end
stop() click to toggle source

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

Returns

The receiver (self).

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

# File lib/rubygame/sound.rb, line 317
def stop
  if channel_active?
    SDL::Mixer.HaltChannel( @channel )
  end

  return self
end
stopped?() click to toggle source

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

# File lib/rubygame/sound.rb, line 329
def stopped?
  (not channel_active?) or (SDL::Mixer.Playing(@channel) == 0)
end
unpause() click to toggle source

Unpause the Sound, 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 sound is not currently paused.

# File lib/rubygame/sound.rb, line 290
def unpause
  if channel_active?
    SDL::Mixer.Resume( @channel )
  end

  return self
end
volume() click to toggle source

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

*NOTE*: Ignores fading in or out.

# File lib/rubygame/sound.rb, line 385
def volume
  @volume
end
volume=( new_vol ) click to toggle source

Set the new volume level of the sound. 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 sound is fading in or out. Be sure to check fading? or rescue from SDLError when using this method.

May raise

SDLError if the sound is fading in or out.

# File lib/rubygame/sound.rb, line 401
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 channel_active?
    if fading?
      raise Rubygame::SDLError, "cannot set Sound volume while fading"
    else
      SDL::Mixer.Volume( @channel, (SDL::Mixer::MAX_VOLUME * new_vol).to_i )
    end
  end

  @volume = new_vol
end

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