Class Rubygame::Sound
In: lib/rubygame/sound.rb
Parent: Object

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.

Methods

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

Included Modules

Rubygame::NamedResource

Public Class methods

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.

[Source]

# 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 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.

[Source]

# 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

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

Raises NotImplementedError.

[Source]

# 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 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.

[Source]

# 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

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)

[Source]

# 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

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.

[Source]

# File lib/rubygame/sound.rb, line 127
  def initialize_copy( other )
    @struct  = other.struct
    @volume  = other.volume
    @channel = -1
  end

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.

[Source]

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

    return self
  end

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

[Source]

# 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 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 );

[Source]

# 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

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

[Source]

# 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 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.

[Source]

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

    return self
  end

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

[Source]

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

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.

[Source]

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

    return self
  end

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

*NOTE*: Ignores fading in or out.

[Source]

# File lib/rubygame/sound.rb, line 385
  def volume
    @volume
  end

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.

[Source]

# 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

[Validate]