1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
<html>
<head>
<title>DevMaster.net - OpenAL Tutorials: Lesson 2</title>
</head>
<body>
<div align="center">
<IMG SRC="http://games.dev.java.net/images/navbar.gif" WIDTH=454 HEIGHT=43 BORDER=0 ALT="" USEMAP="#navbar_Map"></div>
<MAP NAME="navbar_Map">
<AREA SHAPE="rect" ALT="Wiki" COORDS="340,0,386,43" HREF="http://wiki.java.net/bin/view/Games">
<AREA SHAPE="rect" ALT="Weblogs" COORDS="286,0,339,43" HREF="http://weblogs.java.net/weblogs/project/games">
<AREA SHAPE="rect" ALT="Forums" COORDS="216,0,285,43" HREF="http://games.dev.java.net/forums">
<AREA SHAPE="rect" ALT="JavaGames Home" COORDS="91,0,215,43" HREF="http://community.java.net/games">
<AREA SHAPE="rect" ALT="www.java.net" COORDS="1,1,91,44" HREF="http://www.java.net" TARGET="_self">
</MAP>
<br>
<table border="0" cellspacing="0" style="border-collapse: collapse" width="100%" cellpadding="0" id="AutoNumber1" height="12" bgcolor="#666699">
<tr>
<td width="47%" height="12"><b><font color="#FFFFFF">OpenAL Tutorials</font></b></td>
<td width="53%" height="12">
<p align="right"><font color="#66CCFF"> </font><font color="#66FF99"> </font><a href="http://devmaster.net/"><font color="#66FF99">DevMaster.net</font></a></td>
</tr>
</table>
<p align="left" class="title"><span class="title"><font size="5">Looping and
Fade-away</font></span><font size="4"><br>
<b>Lesson 2</b></font></p>
<p align="right" class="title"> <span class="author">Author: <a href="mailto:lightonthewater@hotmail.com"><font color="#888888">Jesse
Maurais<br>
</font></a></span><span class="author">Adapted for Java By: <a href="mailto:athomas@dev.java.net"><font color="#888888">Athomas
Goldberg </font></a> </span></p>
<p>Hope you found the last tutorial of some use. I know I did. This will be a
real quick and easy tutorial. It won't get too much more complicated at this
point.</p>
<pre >
<font color="#0000FF">import </font>java.nio.ByteBuffer;
<font color="#0000FF">import </font>net.java.games.joal.AL;
<font color="#0000FF">import</font> net.java.games.joal.ALC;
<font color="#0000FF">import</font> net.java.games.joal.ALFactory;
<font color="#0000FF">import</font> net.java.games.joal.util.ALut;
<font color="#0000FF">public</font> <font color="#0000FF">class</font> LoopingAndFadeaway {
<font color="#0000FF">static</font> <font color="#0000FF">int</font>[] buffer = <font color="#0000FF">new</font> <font color="#0000FF">int</font>[1];
<font color="#0000FF">static</font> <font color="#0000FF">int</font>[] source = <font color="#0000FF">new</font> <font color="#0000FF">int</font>[1];
<font color="#0000FF">static</font> <font color="#0000FF">float</font>[] sourcePos = { 0.0f, 0.0f, 0.0f };
<font color="#0000FF">static</font> <font color="#0000FF">float</font>[] sourceVel = { 0.0f, 0.0f, 0.1f };
<font color="#0000FF">static</font> <font color="#0000FF">float</font>[] listenerPos = { 0.0f, 0.0f, 0.0f };
<font color="#0000FF">static</font> <font color="#0000FF">float</font>[] listenerVel = { 0.0f, 0.0f, 0.0f };
<font color="#0000FF">static</font> <font color="#0000FF">float</font>[] listenerOri = { 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, 0.0f };
<font color="#0000FF">static</font> AL al;
<font color="#0000FF">static</font> ALC alc;</p></pre>
<p>There is only one change in the code since the last tutorial in this fist
section. It is that we altered the sources velocity. It's 'z' field is now 0.1.</p>
<pre class=code>
<font color="#0000FF">static</font> <font color="#0000FF">int</font> loadALData() {
<font color="#0000FF">if</font> (al.alGetError() != AL.AL_NO_ERROR) {
<font color="#0000FF">return</font> AL.AL_FALSE;
}
<font color="#0000FF">int</font>[] format = <font color="#0000FF">new</font> <font color="#0000FF">int</font>[1];
<font color="#0000FF">int</font>[] size = <font color="#0000FF">new</font> <font color="#0000FF">int</font>[1];
ByteBuffer[] data = <font color="#0000FF">new</font> ByteBuffer[1];
<font color="#0000FF">int</font>[] freq = <font color="#0000FF">new</font> <font color="#0000FF">int</font>[1];
<font color="#0000FF">int</font>[] loop = <font color="#0000FF">new</font> <font color="#0000FF">int</font>[1];
<font color="#006600"> // Load wav data into a buffer.</font>
al.alGenBuffers(1, buffer);
<font color="#0000FF">if </font>(al.alGetError() != AL.AL_NO_ERROR)
<font color="#0000FF">return</font> AL.AL_FALSE;
ALut.alutLoadWAVFile(
"wavdata/Footsteps.wav",
format,
data,
size,
freq,
loop);
al.alBufferData(buffer[0], format[0], data[0], size[0], freq[0]);
ALut.alutUnloadWAV(format[0], data[0], size[0], freq[0]);
al.alGenSources(1, source);
al.alSourcei(source[0], AL.AL_BUFFER, buffer[0]);
al.alSourcef(source[0], AL.AL_PITCH, 1.0f);
al.alSourcef(source[0], AL.AL_GAIN, 1.0f);
al.alSourcefv(source[0], AL.AL_POSITION, sourcePos);
al.alSourcefv(source[0], AL.AL_POSITION, sourceVel);
al.alSourcei(source[0], AL.AL_LOOPING, AL.AL_TRUE);
<font color="#0000FF"> if </font>(al.alGetError() != AL.AL_NO_ERROR) {
<font color="#0000FF">return</font> AL.AL_FALSE;
}
<font color="#0000FF">return</font> AL.AL_TRUE;
}</pre>
<p>Two changes in this section. First we are loading the file "Footsteps.wav".
We are also explicitly setting the sources 'AL_LOOPING' value to 'AL_TRUE'.
What this means is that when the source is prompted to play it will continue
to play until stopped. It will play over again after the sound clip has ended.</p>
<pre class=code>
<font color="#0000FF">static <span class=codeKeyword>void</span> </font>setListenerValues() {
al.alListenerfv(AL.AL_POSITION, listenerPos);
al.alListenerfv(AL.AL_VELOCITY, listenerVel);
al.alListenerfv(AL.AL_ORIENTATION, listenerOri);
}
<font color="#0000FF">static <span class=codeKeyword>void</span> </font>killALData() {
al.alDeleteBuffers(1, buffer);
al.alDeleteSources(1, source);
Alut.alutExit();
}
</pre>
<p>Nothing has changed here.</p>
<pre class=code>
<font color="#0000FF">public static void main</font>(String[] args) {
ALut.alutInit();
al = ALFactory.getAL();
<font color="#0000FF">if</font>(loadALData() == AL.AL_FALSE) {
System.exit(1);
};
setListenerValues();
al.alSourcePlay(source[0]);
<font color="#0000FF">long</font> startTime = System.currentTimeMillis();
<font color="#0000FF">long</font> elapsed = 0;
<font color="#0000FF">long</font> ticker = 0;
<font color="#0000FF">long</font> lastTime = 0;
<font color="#0000FF">while</font> (elapsed < 5000) {
elapsed = System.currentTimeMillis() - startTime;
<font color="#0000FF">if</font> (ticker > 100) {
ticker = 0;
sourcePos[0] += sourceVel[0];
sourcePos[1] += sourceVel[1];
sourcePos[2] += sourceVel[2];
al.alSourcefv(
source[0],
AL.AL_POSITION,
sourcePos);
}
ticker += System.currentTimeMillis() - lastTime;
lastTime = System.currentTimeMillis();
}
ALut.alutExit();
}
}</pre>
<p>The only thing that has changed in this code is the loop. Instead of playing
and stopping the audio sample it will slowly get quieter as the sources position
grows more distant. We do this by slowly incrementing the position by it's
velocity over time. The time is sampled by checking the system clock which gives
us a tick count. It shouldn't be necessary to change this, but if the audio clip
fades too fast you might want to change 100 to some higher number. </p>
<p><a href="lesson2.zip">Download the Java
Source and Ant Build file.</a></p>
<p align="right"><b> </b></p>
<table border="0" cellspacing="1" style="border-collapse: collapse" width="100%" id="AutoNumber2" bgcolor="#666699">
<tr>
<td width="47%"> <p dir="ltr"><font color="#FFFFFF" size="1">� 2003 DevMaster.net.
All rights reserved.</font></td>
<td width="53%"> <p align="right" dir="ltr"><font color="#FFFFFF"><a href="mailto:webmaster@devmaster.net">
<font size="1">Contact us</font></a><font size="1"> if you want to write
for us or for any comments, suggestions, or feedback.</font></font></td>
</tr>
</table>
</body>
</html>
|
