Difference between revisions of "Development/Tutorials/Games/KALEngine"

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m (remove installation section, i suppose gluon package is available for distros)
m (Hello Word: add new code)
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Phonon is not really designed to handle multiple sounds at the same time. Gluon's audio module is made for games and create one thread per sound, using the openAL library. You also get all the other openAL goodness like 3D sounds, effects and multichannel.
 
Phonon is not really designed to handle multiple sounds at the same time. Gluon's audio module is made for games and create one thread per sound, using the openAL library. You also get all the other openAL goodness like 3D sounds, effects and multichannel.
  
== Hello Word ==
+
== The Code ==
In this example, we will play a "Hello Word". We don't need to specify any sound file, openAL provides a default sound itself.
+
In this example, we will play a simple sound file as "Hello Word".
  
 
<syntaxhighlight lang="cpp-qt">
 
<syntaxhighlight lang="cpp-qt">
 +
#include "audio/sound.h"
  
#include <KALEngine>
+
#include <QtCore/QDebug>
#include <KALSource>
+
#include <KDebug>
+
  
int main(int argc, char **argv)
+
int main( int argc, char* argv[] )
 
{
 
{
     // create an OpenAL object
+
     // create a sound object
     KALEngine soundEngine;
+
     GluonAudio::Sound* sound = new GluonAudio::Sound;
    // initialize OpenAL context and device
+
    soundEngine.init();  
+
  
     // create a sound, since we haven't specified any filename in the constructor, it will play the "Hello World"
+
     // load KDE's log in sound to the object
     KALSource *sound = new KALSource();
+
    sound->load( "/usr/share/sounds/KDE-Sys-Log-In-Long.ogg" );
 +
 
 +
    // set sound volume, it can be between 0 and 1
 +
    sound->setVolume( 0.9 );
 +
 
 +
    // print the elapsed time until the sound has finished playing
 +
     qDebug() << "Playing sound with duration" << sound->duration() << "seconds.";
  
 
     // play the sound
 
     // play the sound
 
     sound->play();
 
     sound->play();
  
     // print the elapsed time until the sound has finished playing
+
     // wait until playing is finished
     while (sound->status() == AL_PLAYING)
+
     while( sound->isPlaying() );
    {
+
        kDebug() << sound->elapsedTime();
+
    }
+
  
 
     // clear the buffer
 
     // clear the buffer
 
     delete sound;
 
     delete sound;
    // ...and close the device
 
    soundEngine.shutdown();
 
  
 
     return 0;
 
     return 0;
 
}
 
}
 
 
 
</syntaxhighlight>
 
</syntaxhighlight>
  

Revision as of 19:21, 13 May 2013

KALEngine tutorial
Tutorial Series   KALEngine developement
Prerequisites   None
What's Next   Nothing at the moment
Further Reading   KGLEngine2d's code

Contents

Abstract

Phonon is not really designed to handle multiple sounds at the same time. Gluon's audio module is made for games and create one thread per sound, using the openAL library. You also get all the other openAL goodness like 3D sounds, effects and multichannel.

The Code

In this example, we will play a simple sound file as "Hello Word".

#include "audio/sound.h"
 
#include <QtCore/QDebug>
 
int main( int argc, char* argv[] )
{
    // create a sound object
    GluonAudio::Sound* sound = new GluonAudio::Sound;
 
    // load KDE's log in sound to the object
    sound->load( "/usr/share/sounds/KDE-Sys-Log-In-Long.ogg" );
 
    // set sound volume, it can be between 0 and 1
    sound->setVolume( 0.9 );
 
    // print the elapsed time until the sound has finished playing
    qDebug() << "Playing sound with duration" << sound->duration() << "seconds.";
 
    // play the sound
    sound->play();
 
    // wait until playing is finished
    while( sound->isPlaying() );
 
    // clear the buffer
    delete sound;
 
    return 0;
}

- First, we initialize the sound engine. The init() function can optionally takes one argument, the device name. You can retrieve the list of devices, using this static function :

QStringList devicesList().

- Then, we create a KALsource. KALSource can be used for playing small sounds(shoot, scream, tic, walk, etc). It will load the entire file inside a buffer, so be careful if you try to play a big file using it.

If you want to try playing something else than the default "Hello World", you can download this short simple : [ocean.wav] and replace the sound object definition by:

    KALSource *sound = new KALSource("ocean.wav");

You can only use it to play wav file at the moment, but we hope to bring ogg support soon. For playing music, please wait until KALStream tutorial is up.

- The sound can now be played by simply calling play(). This function is asynchronous, meaning your program doesn't have to wait until the sound has finished playing to continue.

- Then, to know when the sound has ended, we create a loop using status() which returns ever AL_PLAYING or AL_STOPED.

- Inside the loop, we print the time since the sound started playing using elapsedTime(). It returns an ALfloat with the elapsed time expressed in seconds.

- Finally, we have to clear the KALSource buffer by deleting the KALSource pointer and close the device by calling shutdown().

Multi-channel

sound1->play(); sound2->play();

...to develop

3d sound

KALSource->setPosition(x,y,z) ...to develop


Ktip.png
 
Tip
For more information on how OpenAL works, see the documentation [OpenAL programmers Guide ]


noframe
 
TODO
Create KALStream

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