Learning Processing: A Beginner's Guide to Programming Images ...

384 Learning Processing
Just as with images, loading the sound fi le from the hard drive is a slow process so the previous line of
code should be placed in setup( ) so as to not hamper the speed of draw( ) .
Th e type of sound fi le compatible with Sonia is somewhat limited. Only sounds that are formatted as WAV
or AIFF fi les (16-bit mono or stereo) are allowed. If you want to use a sound fi le that is not stored in a
compatible format, you could download a free audio editor, such as Audacity ( http://audacity.sourceforge.net/ )
and convert the fi le. Most audio fi les can be saved raw or with compression. Sonia only works with raw fi les.
However, in the next section, we will demonstrate how compressed (MP3) fi les can be played with the
ESS library.
Once the sound is loaded, playing is easy.
dingdong.play();
Th e following example plays a doorbell sound whenever the mouse is clicked on the graphical doorbell.
Th is Doorbell class implements simple button functionality (rollover and click) and just happens to
be a solution for Exercise 9–8 . Th e code for the new concepts (related to sound playback) is shown in
bold type .
Example 20-2: Doorbell with Sonia
// Import the Sonia library
import pitaru.sonia_v2_9.*;
// A sample object (for a sound)
Sample dingdong;
// A doorbell object (that will trigger the sound)
Doorbell doorbell;
void setup() {
size(200,200);
Sonia.start(this); // Start Sonia engine.
// Create a new sample object.
dingdong = new Sample( " dingdong.wav " );
// Create a new doorbell
doorbell = new Doorbell(150,100,32);
smooth();
}
void draw() {
background(255);
// Show the doorbell
doorbell.display(mouseX,mouseY);
}
The play() function plays the sound sample once.
fi g. 20.1