Add sound to my Cocos2dx game

At some point you will want to add some awesome sounds to your game. The way to do it is very simple but before explaining it let's check a couple concepts:

Background Music: The background music (or BGM for short) are the sounds that are played in the background. Normally this music is played at low volume to keep it out of the focus of the player and avoid obscuring sounds that are more important. BGM is normally long and there is only one at a time (Except maybe at some points where you are going to a new level and there is a fade in and fade out).

Effects: This kind of sound is short and normally represents a game event (Walking, running, jumping, shooting, etc). There are tons of effects in a game and they are played constantly.

Depending on the platform you are going to run your game the format of the sounds should be different according to documentation.

The module of Cocos2dx that handles music is called CocosDenshion. To use it you must include a .h file in your game:

#include "SimpleAudioEngine.h"

You can use CocosDenshion namespace too:

using namespace CocosDenshion;

To use different formats depending on what platform you are in, you can use this comparison:

#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)

    #define EFFECT_FILE        "effect2.ogg"

#elif( CC_TARGET_PLATFORM == CC_PLATFORM_MARMALADE)

    #define EFFECT_FILE        "effect1.raw"

#else

    #define EFFECT_FILE        "effect1.wav"

#endif // CC_PLATFOR_ANDROID

#if (CC_TARGET_PLATFORM == CC_PLATFORM_WIN32)

    #define MUSIC_FILE        "music.mid"

#elif (CC_TARGET_PLATFORM == CC_PLATFORM_WP8)

    #define MUSIC_FILE        "background.wav"

#elif (CC_TARGET_PLATFORM == CC_PLATFORM_BLACKBERRY || CC_TARGET_PLATFORM == CC_PLATFORM_LINUX )

    #define MUSIC_FILE        "background.ogg"

#elif (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)

    #define MUSIC_FILE        "background.caf"

#else

    #define MUSIC_FILE        "background.mp3"

#endif // CC_PLATFOR_WIN32

I took this fragment of code from the test project on Cocos2dx download. As you can see depending on the platform the #define directive is different, pointing to a file with another format. The files in this case should be located at the Resources folder in your project. If you want to have a folder for sounds you can create it and then reference the files with the relative path from the Resources folder (Something like "sounds/myFile.mp3").

In your init() methods you should preload the sounds you are going to use later. You can do that like this:

SimpleAudioEngine::getInstance()->preloadBackgroundMusic( MUSIC_FILE );

SimpleAudioEngine::getInstance()->preloadEffect( EFFECT_FILE );

Now you can play the sounds wherever you want with:

SimpleAudioEngine::getInstance()->playBackgroundMusic(MUSIC_FILE, true);

SimpleAudioEngine::getInstance()->playEffect(EFFECT_FILE, false, pitch, pan, gain);

There are also functions to stop the playback, pause, resume, etc. To control volume use:

SimpleAudioEngine::getInstance()->setEffectsVolume(volume);

SimpleAudioEngine::getInstance()->setBackgroundMusicVolume(volume);

The volume value must be between 0 and 1.

As a last hint remember to use bitrates that are enough for what you want. Use values around 128kbps - 256kbps, not something like 2822kbps (Yeah, happened to me once and took me a while to notice). You can find more information on supported formats for specific platforms in their respective documentations. In the case of android you can check this.

This should be enough to get you started with the music and effects on Cocos2dx. Good luck and rock on!