Audio

Audio

Chi Chung Ko (National University of Singapore, Singapore) and Chang Dong Cheng (CCS Automation PTE LTD, Singapore)
Copyright: © 2009 |Pages: 12
DOI: 10.4018/978-1-59904-789-8.ch012
OnDemand PDF Download:
$37.50

Abstract

Of all the human perceptions, two of the most important ones are perhaps vision and sound, for which we have developed highly specialized sensors over millions of years of evolution. The creation of a realistic virtual world therefore calls for the development of realistic 3D virtual objects and sceneries supplemented by associated sounds and audio signals. The development of 3D visual objects is of course the main domain of Java 3D. However, as in watching a movie, it is also essential to have realistic sound and audio in some applications. In this chapter, we will discuss how sound and audio can be added and supported by Java 3D. The Java 3D API provides some functionalities to add and control sound in a 3D spatialized manner. It also allows the rendering of aural characteristics for the modeling of real world, synthetic or special acoustical effects (Warren, 2006). From a programming point of view, the inclusion of sound is similar to the addition of light. Both are the results of adding nodes to the scene graph for the virtual world. The addition of a sound node can be accomplished by the abstract Sound class, under which there are three subclasses on BackgroundSound, PointSound, and ConeSound (Osawa, Asai, Takase, & Saito, 2001). Multiple sound sources, each with a reference sound file and associated methods for control and activation, can be included in the scene graph. The relevant sound will become audible whenever the scheduling bound associated with the sound node intersects the activation volume of the listener. By creating an AuralAttributes object and attaching it to a SoundScape leaf node for a certain sound in the scene graph, we can also specify the use of certain acoustical effects in the rendering of the sound. This is done through using the various methods to change important acoustic parameters in the Aura lAttributes object.
Chapter Preview
Top

Backgroundsound

This is a subclass of the Sound class for audio and sound that are unattenuated and nonspatialized. That is, similar to ambient lighting, the sound generated will not have a specific position or direction and will be independent of where the user is in the virtual 3D world. However, unlike a background scenery, more than one BackgroundSound node can be enabled and played at the same time.

Figure 1 shows the code segment in an example for adding a background sound in our virtual 3D world. In line 5, the sound file is opened and loaded by a MediaContainer from the current directory. Alternatively, a path can be specified or the sound data can come from the Internet through a URL such as http://vlab.ee.nus.edu.sg/vlab/sound.wav.

Figure 1.

Code segment for SoundBackgroundPanel.java

Lines 8 to 17 declare some reading and writing capabilities to the sound node created in Line 1. With these capabilities set, it is now possible to change the sound data and alter the enable, loop, release and continuous play functionality of the node through some of the methods in lines 18 to 25.

Specifically, line 18 uses the setSoundData method to change the sound source to correspond to that loaded earlier. Line 19 sets the initial amplitude gain for playing the sound, line 20 uses the setLoop method to specify number of times that sound will be repeated. In the current case, the argument is 0 and the sound will be played once. An argument of –1 will repeat the sound indefinitely.

Line 21 sets the setReleaseEnable flag to false. This flag is only valid when the sound is played once. Setting this flag to true will force the sound to be played until it finishes even in the presence of a stop request.

Similarly, line 22 set the setContinuousEnable flag to false. Setting this to true gives rise to the effect that the sound will be played continuously in a silent mode even if the node is no longer active as when it is outside the scheduling bound. A false setting will play the sound from the beginning when the audio object reenters the scheduling bound.

Complete Chapter List

Search this Book:
Reset
Table of Contents
Preface
Chi Chung Ko
Chapter 1
Chi Chung Ko, Chang Dong Cheng
Web-based virtual reality is fast becoming an important application and technological tools in the next generation of games and simulation as well... Sample PDF
Virtual Reality and Java 3D
$37.50
Chapter 2
Java 3D Overview  (pages 18-31)
Chi Chung Ko, Chang Dong Cheng
In the last chapter, a brief introduction on the creation of 3D content through the use of Java 3D and other programming methodologies for virtual... Sample PDF
Java 3D Overview
$37.50
Chapter 3
Geometry Objects  (pages 32-74)
Chi Chung Ko, Chang Dong Cheng
To create 3D graphics, we have to build graphics or visual objects and position them appropriately in a virtual scene. In general, there are three... Sample PDF
Geometry Objects
$37.50
Chapter 4
Appearance Objects  (pages 75-96)
Chi Chung Ko, Chang Dong Cheng
In the last chapter, the creation of the skeletons or shapes of 3D objects has been discussed through the use of geometry objects in Java 3D. In... Sample PDF
Appearance Objects
$37.50
Chapter 5
Textures  (pages 97-113)
Chi Chung Ko, Chang Dong Cheng
Although extensive use of basic attributes such as color and material will be able to make an object realistic to the human user, it will be time... Sample PDF
Textures
$37.50
Chapter 6
Chi Chung Ko, Chang Dong Cheng
How the properties of virtual 3D objects can be specified and defined has been discussed in earlier chapters. However, how a certain virtual object... Sample PDF
Lighting, Fog, and Background
$37.50
Chapter 7
Animation Objects  (pages 132-158)
Chi Chung Ko, Chang Dong Cheng
We have discussed important Java 3D objects that are basically static in the last few chapters. Starting from this chapter, we will be looking at... Sample PDF
Animation Objects
$37.50
Chapter 8
Interaction  (pages 159-187)
Chi Chung Ko, Chang Dong Cheng
In Chapter VII, we discussed how animation can be applied in Java 3D to increase the visual impact of a virtual 3D world and illustrate the dynamic... Sample PDF
Interaction
$37.50
Chapter 9
Picking  (pages 188-216)
Chi Chung Ko, Chang Dong Cheng
The last two chapters have discussed how animation and interaction can be created in Java 3D to increase visual impact, to show object dynamics and... Sample PDF
Picking
$37.50
Chapter 10
Chi Chung Ko, Chang Dong Cheng
One of the most useful and important advantages of 3D graphics rendering and applications is that there is the possibility for the user to navigate... Sample PDF
Navigation, Input Devices, and Collision
$37.50
Chapter 11
Multiple Views  (pages 238-263)
Chi Chung Ko, Chang Dong Cheng
Our discussions in previous chapters have centered on the creation and interaction of visual objects in a virtual 3D world. The objects and scenes... Sample PDF
Multiple Views
$37.50
Chapter 12
Audio  (pages 264-275)
Chi Chung Ko, Chang Dong Cheng
Of all the human perceptions, two of the most important ones are perhaps vision and sound, for which we have developed highly specialized sensors... Sample PDF
Audio
$37.50
Chapter 13
Chi Chung Ko, Chang Dong Cheng
In this final chapter, we will describe the use of Java 3D as a visualization technology in the development of a Web-based 3D real time oscilloscope... Sample PDF
A Web-Based 3D Real Time Oscilloscope Experiment
$37.50
Appendix A: Downloading Software
Appendix B: Running the Rotating Cube Program
Appendix C: ViewManager
Appendix D: Main Applet for Web-Based 3D Experiment
Appendix E: Scene Graph Implementation for Web-Based 3D Experiment
Appendix F: Knob Class for Web-Based 3D Experiment
Appendix G: Navigation and Collision Detection for Web-Based 3D Experiment
Appendix H: Picking for Web-Based 3D Experiment
Appendix I: Program Summary and Screen Capture
About the Authors