Advanced audio functionality

Setup

It is easy to get started using the SimpleAudioEngine API. There are considerations to keep in mind when using audio in your game. Mostly when operating on mobile devices such as phones and tablets. What happens when you multi-task on your phone and are switching between apps? Or when a phone call comes in? You need to handle these exceptions in your game. Fortunately, we help you here.

In AppDelegate.cpp, notice the following methods:

// This function will be called when the app is inactive. When comes a phone call,
// it's be invoked too
void AppDelegate::applicationDidEnterBackground() {
    Director::getInstance()->stopAnimation();

    // if you use SimpleAudioEngine, it must be pause
    // SimpleAudioEngine::getInstance()->pauseBackgroundMusic();
}

// this function will be called when the app is active again
void AppDelegate::applicationWillEnterForeground() {
    Director::getInstance()->startAnimation();

    // if you use SimpleAudioEngine, it must resume here
    // SimpleAudioEngine::getInstance()->resumeBackgroundMusic();
}

Notice the commented out lines for SimpleAudioEngine? Make sure to uncomment these lines out if you are using audio for background sounds and sound effects.

Pre-loading sound

When your game starts you might want to pre-load the music and effects so they are ready when you need them.

#include "SimpleAudioEngine.h"
using namespace CocosDenshion;

auto audio = SimpleAudioEngine::getInstance();

// pre-loading background music and effects. You could pre-load
// effects, perhaps on app startup so they are already loaded
// when you want to use them.
audio->preloadBackgroundMusic("myMusic1.mp3");
audio->preloadBackgroundMusic("myMusic2.mp3");

audio->preloadEffect("myEffect1.mp3");
audio->preloadEffect("myEffect2.mp3");

// unload a sound from cache. If you are finished with a sound and
// you wont use it anymore in your game. unload it to free up
// resources.
audio->unloadEffect("myEffect1.mp3");

Volume

You can increase and decrease the volume of your sounds and music programmatically.

#include "SimpleAudioEngine.h"
using namespace CocosDenshion;

auto audio = SimpleAudioEngine::getInstance();

// setting the volume specifying value as a float
audio->setEffectsVolume(0.5);
audio->setBackgroundMusicVolume(0.5);