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| author | athomas <[email protected]> | 2003-07-08 18:47:04 +0000 |
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| committer | athomas <[email protected]> | 2003-07-08 18:47:04 +0000 |
| commit | 10cbd4280b5a4a8918602608085844786d4b7070 (patch) | |
| tree | c3a084b2755d9261d94fa8f1bbd1758eb4a0a326 | |
| parent | 49e0d37852d7b9a87fff7cc7e70eb697523ba0c5 (diff) | |
Added lesson 5
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diff --git a/www/devmaster/lesson5.html b/www/devmaster/lesson5.html new file mode 100644 index 0000000..42d1ef5 --- /dev/null +++ b/www/devmaster/lesson5.html @@ -0,0 +1,275 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html> +<head> +<title>Untitled Document</title> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> +<link rel="stylesheet" type="text/css" href="general.css"> +</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> +<br> +OpenAL Tutorials from DevMaster.net. Reprinted with Permission.<br> +<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" valign="middle"><p><b><font color="#FFFFFF">OpenAL + Tutorials</font></b></p></td> + <td width="53%" height="12" align="right" valign="middle"><p align="right"><a href="http://devmaster.net/"><font color="#66FF99">DevMaster.net</font></a></p></td> + </tr> +</table> +<p class="ArticleTitle"><font size="5">Sources Sharing Buffers<br> + </font><strong><font size="4">Lesson 5</font></strong></p> +<p align="right" class="ArticleAuthor">Author: <a href="mailto:[email protected]">Jesse + Maurais<br> + </a>Adapted For Java By: <a href="[email protected]">Athomas + Goldberg </a></p> +<p>At this point in the OpenAL series I will show one method of having your buffers + be shared among many sources. This is a very logical and natural step, and it + is so easy that some of you may have already done this yourself. If you have + you may just skip this tutorial in total and move on. But for those keeners + who want to read all of the info I've got to give, you may find this interesting. + Plus, we will be implementing the Alc layer directly so that we can use some + of that knowledge gained in lesson 4. On top of that we will create a program + you might even use!</p> +<p>Well, here we go. I've decided to only go over bits of the code that are significant, + since most of the code has been repeated so far in the series. Check out the + full source code in the download.</p> +<pre class=code><span class=codeComment><font color="#0000FF">static</font> ALC alc; +<font color="#0000FF">static</font> AL al;<font color="#006600"> + +// These index the buffers.</font></span> +<span class=codeKeyword><font color="#0000FF">public static final int</font></span> THUNDER = 0; +<span class=codeKeyword><font color="#0000FF">public static final int</font></span> WATERDROP = 1; +<span class=codeKeyword><font color="#0000FF">public static final int</font></span> STREAM = 2; +<span class=codeKeyword><font color="#0000FF">public static final int</font></span> RAIN = 3; + +<span class=codeKeyword><font color="#0000FF">public static final int</font></span> CHIMES = 4; +<span class=codeKeyword><font color="#0000FF">public static final int</font></span> OCEAN = 5; +<span class=codeKeyword><font color="#0000FF">public static final int</font></span> NUM_BUFFERS = 6; + +<font color="#006600"><span class=codeComment>// Buffers hold sound data.</span> +</font><font color="#0000FF">static int</font>[] buffers = <font color="#0000FF">new int</font>[NUM_BUFFERS]; + +<span class=codeComment><font color="#006600">// A vector list of sources for multiple emissions.</font></span> +Vector sources = <font color="#0000FF">new </font>Vector(); + +</pre> +<p>First I've written out a few macros that we can use to index the buffer array. + We will be using several wav files so we need quite a few buffers here. Instead + of using an array for storing the sources we will use a Vector. We chose to + do this because it allows us to have a dynamic number of sources. We can just + keep adding sources to the scene until OpenAL runs out of them. This is also + the first tutorial where we will deal with sources as being a resource that + will run out. And yes, they will run out; they are finite.</p> +<pre class=code><font color="#0000FF">static int </font>initOpenAL() { + + ALC.Device device; + ALC.Context context; + String deviceSpecifier; + String deviceName = "DirectSound3D"; + + <span class=codeComment><font color="#006600">// Get handle to device.</font></span> + device = alc.alcOpenDevice(deviceName); + + <font color="#006600"><span class=codeComment>// Get the device specifier.</span></font> + deviceSpecifier = alc.alcGetString(device, ALC.ALC_DEVICE_SPECIFIER); + + System.out.println("Using device " + deviceSpecifier); + + <span class=codeComment><font color="#006600">// Create audio context.</font></span> + context = alc.alcCreateContext(device, <font color="#0000FF">null</font>); + + <span class=codeComment><font color="#006600">// Set active context.</font></span> + alc.alcMakeContextCurrent(context); + + <span class=codeComment><font color="#006600">// Check for an error.</font></span> + <span class=codeKeyword><font color="#0000FF">if </font></span>(alc.alcGetError() != ALC.ALC_NO_ERROR) + <span class=codeKeyword><font color="#0000FF">return</font></span> AL.AL_FALSE; + + <span class=codeKeyword><font color="#0000FF">return</font></span> AL.AL_TRUE; +} +</pre> +<p>This is some sample code from what we learned in the last tutorial. We get + a handle to the device "DirectSound3D", and then obtain a rendering + context for our application. This context is set to current and the function + will check if everything went smoothly before we return success.</p> +<pre class=code><span class=codeKeyword><font color="#0000FF">static void</font></span> exitOpenAL() { + ALC.Context curContext; + ALC.Device curDevice; + + <font color="#006600"><span class=codeComment>// Get the current context.</span></font> + curContext = alc.alcGetCurrentContext(); + + <span class=codeComment><font color="#006600">// Get the device used by that context.</font></span> + curDevice = alc.alcGetContextsDevice(curContext); + +<font color="#006600"> <span class=codeComment>// Reset the current context to NULL.</span> +</font> alc.alcMakeContextCurrent(<font color="#0000FF">null</font>); + +<font color="#006600"> <span class=codeComment>// Release the context and the device.</span> +</font> alc.alcDestroyContext(curContext); + alc.alcCloseDevice(curDevice); +} +</pre> +<p>This will do the opposite we did in the previous code. It retrieves the context + and device that our application was using and releases them. It also sets the + current context to null (the default) which will suspend the processing of any + data sent to OpenAL. It is important to reset the current context to null or + else you will have an invalid context trying to process data. The results of + doing this can be unpredictable.</p> +<p>If you are using a multi-context application you may need to have a more advanced + way of dealing with initialization and shutdown. I would recommend making all + devices and contexts global and closing them individually, rather than retrieving + the current context.</p> +<pre class=code><font color="#0000FF">static int </font>loadALData() { + <font color="#006600"><span class=codeComment>// Variables to load into.</span></font> + <font color="#0000FF">int</font>[] format = new <font color="#0000FF">int</font>[1]; + <font color="#0000FF">int</font>[] size = new <font color="#0000FF">int</font>[1]; + ByteBuffer[] data = new ByteBuffer[1]; + <font color="#0000FF">int</font>[] freq = new <font color="#0000FF">int</font>[1]; + <font color="#0000FF">int</font>[] loop = new <font color="#0000FF">int</font>[1]; + + <span class=codeComment><font color="#006600">// Load wav data into buffers.</font></span> + al.alGenBuffers(NUM_BUFFERS, buffers); + + <span class=codeKeyword><font color="#0000FF">if</font></span>(al.alGetError() != AL.AL_NO_ERROR) + <span class=codeKeyword><font color="#0000FF">return</font></span> AL.AL_FALSE; + + ALut.alutLoadWAVFile("wavdata/thunder.wav", format, data, size, freq, loop); + al.alBufferData(buffers[THUNDER], format[0], data[0], size[0], freq[0]); + ALut.alutUnloadWAV(format[0], data[0], size[0], freq[0]); + + ALut.alutLoadWAVFile("wavdata/waterdrop.wav", format, data, size, freq, loop); + al.alBufferData(buffers[WATERDROP], format[0], data[0], size[0], freq[0]); + ALut.alutUnloadWAV(format[0], data[0], size[0], freq[0]); + + ALut.alutLoadWAVFile("wavdata/stream.wav", format, data, size, freq, loop); + al.alBufferData(buffers[STREAM], format[0], data[0], size[0], freq[0]); + ALut.alutUnloadWAV(format[0], data[0], size[0], freq[0]); + + ALut.alutLoadWAVFile("wavdata/rain.wav", format, data, size, freq, loop); + al.alBufferData(buffers[RAIN], format[0], data[0], size[0], freq[0]); + ALut.alutUnloadWAV(format[0], data[0], size[0], freq[0]); + + ALut.alutLoadWAVFile("wavdata/ocean.wav", format, data, size, freq, loop); + al.alBufferData(buffers[OCEAN], format[0], data[0], size[0], freq[0]); + ALut.alutUnloadWAV(format[0], data[0], size[0], freq[0]); + + ALut.alutLoadWAVFile("wavdata/chimes.wav", format, data, size, freq, loop); + al.alBufferData(buffers[CHIMES], format[0], data[0], size[0], freq[0]); + ALut.alutUnloadWAV(format[0], data[0], size[0], freq[0]); + +<font color="#006600"> <span class=codeComment>// Do another error check and return.</span> + </font><span class=codeKeyword><font color="#0000FF">if</font> </span>(al.alGetError() != AL.AL_NO_ERROR) + <span class=codeKeyword><font color="#0000FF">return</font></span> AL.AL_FALSE; + + <span class=codeKeyword><font color="#0000FF">return</font></span> AL.AL_TRUE; +} +</pre> +<p>We've totally removed the source generation from this function. That's because + from now on we will be initializing the sources separately.</p> +<pre class=code><span class=codeKeyword><font color="#0000FF">static void</font></span><font color="#0000FF"> </font>addSource(int type) { + <font color="#0000FF">int[]</font> source = <font color="#0000FF">new int</font>[1]; + + al.alGenSources(1, source); + + <span class=codeKeyword><font color="#0000FF">if</font> </span>(al.alGetError() != AL.AL_NO_ERROR) { + System.err.println("Error generating audio source."); + System.exit(1); + } + + al.alSourcei (source[0], AL.AL_BUFFER, buffers[type]); + al.alSourcef (source[0], AL.AL_PITCH, 1.0 ); + al.alSourcef (source[0], AL.AL_GAIN, 1.0 ); + al.alSourcefv(source[0], AL.AL_POSITION, sourcePos ); + al.alSourcefv(source[0], AL.AL_VELOCITY, sourceVel ); + al.alSourcei (source[0], AL.AL_LOOPING, AL.AL_TRUE ); + + al.alSourcePlay(source); + + sources.put(new Integer(source[0])); +} + +</pre> +<p>Here's the function that will generate the sources for us. This function will + generate a single source for any one of the loaded buffers we generated in the + previous source. Given the buffer index 'type', which is one of the macros we + created right from the start of this tutorial. We do an error check to make + sure we have a source to play (like I said, they are finite). If a source cannot + be allocated then the program will exit.</p> +<pre class=code><span class=codeKeyword><font color="#0000FF">static void</font></span><font color="#0000FF"> </font>killALData() { + + Iterator iter = sources.iterator(); + <span class=codeKeyword><font color="#000000">while</font></span>(iter.hasNext()) { + al.alDeleteSources(1, <font color="#0000FF">new int</font>[] { ((Integer)iter.next()).intValue() }); + } + sources.clear(); + al.alDeleteBuffers(NUM_BUFFERS, buffers); + exitOpenAL(); +} +</pre> +<p>This function has been modified a bit to accommodate the Vector. We have to + delete each source in the list individually and then clear the list which will + effectively destroy it.</p> +<pre class=code><font color="#0000FF"> char</font>[] c = <font color="#0000FF">new char</font>[1]; + +<font color="#0000FF"> </font><font color="#0000FF">while</font>(c[0] != 'q') { +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF">try</font> { +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>BufferedReader buf = +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF">new</font> BufferedReader(<font color="#0000FF">new</font> InputStreamReader(System.in)); +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>System.out.println("Press a key and hit ENTER: " + +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>"\t'w' for Water Drop\n" + +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>"\t't' for Thunder\n" + +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>"\t's' for Stream\n" + +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>"\t'r' for Rain\n" + +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>"\t'o' for Ocean\n" + +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>"\t'c' for Chimes\n" + +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>"\n'q' to Quit\n"); +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font>buf.read(c); +<font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF"> </font><font color="#0000FF">switch</font>(c[0]) { +<font color="#0000FF"> case</font> 'w': addSource(WATERDROP); <font color="#0000FF">break</font>; +<font color="#0000FF"></font><font color="#0000FF"> case</font> 't': addSource(THUNDER); <font color="#0000FF">break</font>; +<font color="#0000FF"></font><font color="#0000FF"> case</font> 's': addSource(STREAM); <font color="#0000FF">break</font>; +<font color="#0000FF"></font><font color="#0000FF"> case</font> 'r': addSource(RAIN); <font color="#0000FF">break</font>; +<font color="#0000FF"></font><font color="#0000FF"> case</font> 'o': addSource(OCEAN); <font color="#0000FF">break</font>; +<font color="#0000FF"></font><font color="#0000FF"> case</font> 'c': addSource(CHIMES); <font color="#0000FF">break</font>; +<font color="#0000FF"></font>} +<font color="#0000FF"> </font><font color="#0000FF"> </font>} <font color="#0000FF">catch</font> (IOException e) { + System.exit(1); +<font color="#0000FF"> </font><font color="#0000FF"> </font>} +<font color="#0000FF"> </font>}</pre> +<p>Here is the programs inner loop taken straight out of our main. Basically it + waits for some keyboard input and on certain key hits it will create a new source + of a certain type and add it to the audio scene. Essentially what we have created + here is something like one of those nature tapes that people listen to for relaxation. + Ours is a little better since it allows the user to customize which sounds that + they want in the background. Pretty neat eh? I've been listening to mine while + I code. It's a Zen experience (I'm listening to it right now).</p> +<p>The program can be expanded for using more wav files, and have the added feature + of placing the sources around the scene in arbitrary positions. You could even + allow for sources to play with a given frequency rather than have them loop. + However this would require GUI routines that go beyond the scope of the tutorial. + A full featured "Weathering Engine" would be a nifty program to make + though. ;)</p> +<p>Download the Java Files and Ant build script</p> +<table border="0" cellspacing="1" style="border-collapse: collapse" width="100%" id="AutoNumber2" bgcolor="#666699"> + <tr> + <td width="40%"> <p dir="ltr"><font color="#FFFFFF" size="2">� 2003 DevMaster.net. + All rights reserved.</font></td> + <td width="60%"> <p align="right" dir="ltr"><font size="2"><a href="mailto:[email protected]"> + <font color="#FFFFFF">Contact us</font></a><font color="#FFFFFF"> if you + want to write for us or for any comments, suggestions, or feedback.</font></font></td> + </tr> +</table> +</body> +</html> diff --git a/www/devmaster/lesson5.zip b/www/devmaster/lesson5.zip Binary files differnew file mode 100644 index 0000000..8e08f5f --- /dev/null +++ b/www/devmaster/lesson5.zip diff --git a/www/index.html b/www/index.html index c3fdf31..8e09685 100644 --- a/www/index.html +++ b/www/index.html @@ -102,6 +102,8 @@ Sources </li> <li><a href="devmaster/lesson4.html">lesson 4</a>: A Closer Look at the ALC</li> + <li><a href="devmaster/lesson5.html">lesson 5:</a> Sources + Sharing Buffers</li> </ul> </li> </ul></td> |