[JAVA][Beginning Java 8 Games Development]

Chapter 15 ■ Implementing Game Audio Assets: Using the JavaFX AudioClip Class Audio Sequencing Engine
JavaFX AudioClip Class: A Digital Audio Sequencer
The public final AudioClip class is part of the javafx.scene.media package, and is essentially a digital audio sample
playback and audio sequencing engine that is designed to use short audio snippets or “samples” to create more
complex audio performances. This is why this class is the perfect digital audio media playback class to use for your
Java 8 game development. As you can see by the Java inheritance hierarchy shown below, the JavaFX AudioClip
class is a direct subclass of the java.lang.Object master class. This signifies that the AudioClip class has been “scratch
coded” specifically for the purpose of being a digital audio sequencing engine.
java.lang.Object
> javafx.scene.media.AudioClip
Your AudioClip objects will each reference one digital audio sample in memory. These can be triggered with
virtually zero latency, which is what makes this class the perfect class to use for Java 8 games development. AudioClip
objects are loaded similarly to Media (long-form audio or video) objects, using URL objects, but have a vastly different
behavior. For example, a Media object cannot play itself; it will need a MediaPlayer object, and also the MediaView
object, if it contains digital video. Media objects would be better suited for long-form digital audio assets (like
music), which cannot fit in memory all at the same time, and must be streamed for optimal memory utilization. A
MediaPlayer will only have enough decompressed digital audio data “pre-rolled” into memory to play for a short
amount of time, so a MediaPlayer approach is much more memory efficient for long digital audio clips, especially if
they are compressed.
The AudioClip object is usable immediately upon instantiation, as you’ll see later on during this chapter, and
this is an important attribute to have when it comes to Java 8 game development. AudioClip object playback behavior
can be said to be “fire and forget,” which means that once one of your playiSound() method calls is invoked, your only
operable control at that point over the digital audio sample is to call the AudioClip .stop() method.
Interestingly, your AudioClip objects may also be triggered (played) multiple times, and AudioClips can even be
triggered simultaneously, as you will see a bit later on during this chapter. To accomplish this same result by using a
Media object, you would have to create a new MediaPlayer object for each sound that you want to play in parallel.
The reason that the AudioClip object is so versatile (responsive) is because your AudioClip objects are stored in
memory. The AudioClip object uses a raw, uncompressed digital audio sample representing the entire sound. This is
placed into memory in its raw, uncompressed state, which is why in the next section of the chapter we’re going to use
the WAVE audio file format. This audio format applies zero compression, and thus, the resulting file size for optimized
digital audio samples will also represent the amount of system memory that each of these samples will utilize.
What is really impressive about the AudioClip class, however, is the amount of power it gives developers via its
properties and the three overloaded .play() method calls. You can set up sample playback priorities, shift the pitch
(frequency of the sound) up to 8 times (higher octaves) or down to 1/8th (lower octaves), pan the sound anywhere in the
spatial spectrum, control the left and right balance of the sound, control the volume (or amplitude) of the sound, and
control the number of times the sound is played, from once to forever, using the AudioClip INDEFINITE constant.
Besides the getter and setter methods for these AudioClip properties, there are .play() and .stop() methods as
well as three (overloaded) .play() methods: one for simple (default) playback; one where you can specify volume; and
one where you can specify volume, balance, frequency rate (pitch shifting factor), panning, and sample priority.
The key to controlling the AudioClip object is to call one of the three .play() methods based upon how you want
to control the sample playback. Use .play() for straightforward playback, as we will be doing during this chapter; or
use .play(double volume) to play your AudioClip object at a relative volume level from 0.0 (off) to 1.0 (full); or use the
.play(double volume, double balance, double rate, double pan, double priority) to play your AudioClip object at a
relative volume (0.0 to 1.0), a relative balance (-1.0 left, 0.0 center, 1.0 right), pitch shift rate (0.125 to 8.0), relative pan
(-1.0 left, 0.0 center, 1.0 right); and priority integer, which specifies which samples get played over others, which, due
to low resources and low priority, may not get played. Let’s get into using Audacity to optimize our samples next!
324
www.it-ebooks.info