Let’s Make a Game 5: Sounds

Shoes doesn’t have great audio support right now, but it ships with multimedia capabilities provided by the VideoLAN and ffmpeg libraries.

To use audio, use the video keyword with a wav or mp3.  You can hide the resulting video object so it won’t take up layout space.  One limitation of audio playback is you only have a single stereo channel, which means you can’t multiplex audio (I might be wrong, but I haven’t found a way to do this).  This is usually required in a game, so our audio will be fairly limited, but good enough to get things going.

I’ve made a small class to manage audio in our snake game.  It makes managing sounds easier:

• Add sounds with @sounds.add_sound :death, 'death.mp3'
• Playing a sound will automatically stop other sounds
• I’ve bundled sounds for collecting items and death

The current version of this tutorial in my snake-shoes git repository is here: snake-shoes-6d88.  You can download the sounds and code there.

The sound class looks like this:

Other Options for Sound

One way of handling audio would be to rely on a library like libSDL.  Rubysql would be a good starting point.

Dependencies

If your Shoes applications start to require libraries, you can manage them with Shoes.setup:

Shoes.setup do
  gem 'library'
end