Sound

Here we have recipes for doing things with sound.

Loading and playing a sound

In order to play a sound in your game, you first have to put a sound file into your assets project in the right location. All game assets (sounds and images) are placed into this directory (which is relative to the root of your game project):

assets/src/main/resources/assets

Inside that directory, you can arrange things however you like, but one common approach is to have images and sounds subdirectories, so we will follow that approach in this example and add:

assets/src/main/resource/assets/sounds/ding.mp3

Now we can load and play our new sound easily. The following code loads the sound when the game starts up and plays it whenever any mouse button is depressed:

import playn.core.*;

public class YourGame extends SceneGame {
  public YourGame (Platform plat) {
    final Sound sound = plat.assets().getSound("sounds/ding");

    plat.input().mouseEvents.connect(new Mouse.ButtonSlot() {
      public void onEmit (Mouse.ButtonEvent ev) {
        if (ev.down) sound.play();
      }
    });
    // ...
  }
}

Note that when we load the sound, we don’t supply the .mp3 suffix for the file. This is because PlayN supports different audio formats for different backends. For example, on the iOS backend, it is recommended to use CAF (uncompressed) and AIFC (compressed) sound formats rather than WAV and MP3. PlayN will look for sounds using the suffixes preferred by the backend in question and then fall back to the more general suffixes if it cannot find the preferred suffix.

The search order for each platform is as follows:

• Java: .wav, .mp3
• HTML: .mp3
• Android: .mp3
• RoboVM: .caf, .aifc, .mp3

A good practice is to store all of your sounds as uncompressed .wav files for use during development and then have your build automatically generate appropriate compressed formats for the backends to which you are deploying. This ensures that you always have a perfect copy of your source audio from which you can transcode to new formats if and when they arise. If you store your source audio in .mp3 format, then it is already compressed and transcoding it to another format will result in reduced sound quality.