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| author | athomas <[email protected]> | 2003-06-28 20:07:15 +0000 |
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| committer | athomas <[email protected]> | 2003-06-28 20:07:15 +0000 |
| commit | 4e95ad3efeb9346e2ade9c4cff6b344abf7be145 (patch) | |
| tree | e70a13876e8c5a9589cce61fff6a6f7c92875288 /www/devmaster/lesson1.htm | |
| parent | 8d31a0e75c692aec53abb7e21cb4a2b7ea542e8a (diff) | |
checking in Lesson 2
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diff --git a/www/devmaster/lesson1.htm b/www/devmaster/lesson1.htm deleted file mode 100644 index d2b401d..0000000 --- a/www/devmaster/lesson1.htm +++ /dev/null @@ -1,282 +0,0 @@ -<!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 align="left" class="title"><span class="title"><font size="5">Single Static -Source</font></span><font size="4"><br> -<b>Lesson 1</b></font></p> - -<p align="right" class="title"> <span class="author">Author: <a href="mailto:[email protected]"><font color="#888888">Jesse - Maurais<br> - </font></a></span>Adapted for Java by: <a href="mailto:[email protected]"><font color="#888888">Athomas - Goldberg</font></a></p> </p> - <p>Welcome to the exciting world of OpenAL! OpenAL -is still in a stage of growth, and even though there is an ever larger following -to the API it still hasn't reached it's full potential. One of the big reasons -for this is that there is still not yet hardware acceleration built in for -specific cards. However, Creative Labs is a major contributor to the OpenAL -project and also happens to be one of the largest soundcard manufacturers. So -there is a promise of hardware accelerated features in the near future. OpenAL's -only other major contributor, Loki, has gone the way of the dinosaur. So the -future of OpenAL on Linux platforms is uncertain. You can still obtain the Linux -binaries on some more obscure websites.</p> -<p>OpenAL has also not been seen in many major -commercial products, which may have also hurt it's growth. As far as I know the -only pc game to use OpenAL has been Metal Gear 2 (although recently I've -discovered that Unreal 2 does as well). The popular modeling program, Blender3D, -was also known to use OpenAL for all it's audio playback. Aside from these -however the only other OpenAL uses have been in the sdk examples and a few -obscure tutorials on the internet.</p> -<p>But lets face it, OpenAL has a lot of -potential. There are many other audio libraries that claim to work with the -hardware on a lower level (and this may be true), but the designers of OpenAL -did several things in it's design which make it a superior API. First of all -they emulated the OpenGL API which is one of the best ever designed. The API -style is flexible, so different coding methods and hardware implementations will -take advantage of this. People who have had a lot of experience with OpenGL will -be able to pick up OpenAL quite fast. OpenAL also has the advantage of creating -3D surround sound which a lot of other API's cannot boast. On top of all of that -it also has the ability to extend itself into EAX and AC3 flawlessly. To my -knowledge no other audio library has that capability.</p> -<p>If you still haven't found a reason here to use -OpenAL then here's another. It's just cool. It's a nice looking API and will -integrate well into your code. You will be able to do many cool sound effects -with it. But before we do that we have to learn the basics.</p> - -<p>So let's get coding!</p> -<pre class=code><font color="#0000FF">import</font> net.java.games.joal.*; -<font color="#0000FF">import</font> net.java.games.joal.util.*; -<font color="#0000FF">import</font> java.io.*; -<font color="#0000FF">import</font> java.nio.ByteBuffer;</pre> -<pre class=code><font color="#0000FF">public</font> <font color="#0000FF">class</font> SingleStaticSource { - - <font color="#0000FF"><span class=codeComment>static</span></font><span class=codeComment> AL al = ALFactory.getAL(); - - <font color="#006600">// Buffers hold sound data.</font></span> - <font color="#0000FF">static int</font>[] buffer = new <font color="#0000FF">int</font>[1];; - -<span class=codeComment> <font color="#006600">// Sources are points emitting sound.</font></span> - <font color="#0000FF">static int</font>[] source = <font color="#0000FF">new</font> <font color="#0000FF">int</font>[1]; -</pre> -<p>Those familiar with OpenGL know that it uses "texture objects" (or "texture -names") to handle textures used by a program. OpenAL does a similar thing with -audio samples. There are essentially 3 kinds of objects in OpenAL. A buffer -which stores all the information about how a sound should be played and the -sound data itself, and a source which is a point in space that emits a sound. -It's important to understand that a source is not itself an audio sample. A -source only plays back sound data from a buffer bound to it. The source is also -given special properties like position and velocity. </p> -<p>The third object which I have not mentioned yet is the listener. There is -only one listener which represents where 'you' are, the user. The listener -properties along with the source properties determine how the audio sample will -be heard. For example their relative positions will determine the intensity of -the sound.</p> - -<pre class=code> -<span class=codeComment><font color="#006600"> // Position of the source sound.</font></span> -<font color="#0000FF"> static float</font>[] sourcePos = { 0.0f, 0.0f, 0.0f }; -<font color="#006600"> -<span class=codeComment> // Velocity of the source sound.</span></font> -<font color="#0000FF"> static float</font>[] sourceVel = { 0.0f, 0.0f, 0.0f }; - -<span class=codeComment> <font color="#006600">// Position of the listener.</font></span> - <font color="#0000FF">static float</font>[] listenerPos = { 0.0f, 0.0f, 0.0f }; - -<span class=codeComment> <font color="#006600">// Velocity of the listener.</font></span> - <font color="#0000FF">static float</font>[] listenerVel = { 0.0f, 0.0f, 0.0f }; - -<span class=codeComment> <font color="#006600">// Orientation of the listener. (first 3 elements are "at", second 3 are "up")</font></span> - <font color="#0000FF">static float</font>[] listenerOri = { 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, 0.0f }; -</pre> - -<p>In the above code we specify the position and velocity of the source and listener - objects. These arrays are vector based Cartesian coordinates. You could easily - build a structure or class to do the same thing. In this example I used arrays - for simplicity.</p> -<p>Here we will create a function that loads all of our sound data from a file. -</p> -<pre class=code> <font color="#0000FF">static int</font> LoadALData() { - -<span class=codeComment> <font color="#006600">// variables to load into</font> - - <font color="#0000FF">int</font>[] format = <font color="#0000FF">new int</font>[1];<br> <font color="#0000FF">int</font>[] size = <font color="#0000FF">new int</font>[1];<br> ByteBuffer[] data = <font color="#0000FF">new</font> ByteBuffer[1];<br> <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];<br></span> - <font color="#006600">// Load wav data into a buffer.</font> - al.alGenBuffers(1, buffer); - <span class=codeKeyword>if</span> (al.alGetError() != AL.AL_NO_ERROR) - <span class=codeKeyword> return</span> AL.AL_FALSE; - - ALut.alutLoadWAVFile("wavdata/FancyPants.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]); -</pre> -<p>The function 'alGenBuffers' will create the buffer objects and store them in -the variable we passed it. It's important to do an error check to make sure -everything went smoothly. There may be a case in which OpenAL could not generate -a buffer object due to a lack of memory. In this case it would set the error -bit.</p> -<p>The ALut is very helpful here. It opens up the file for us and gives us all - the information we need to create the buffer. And after we have attached all - this data to the buffer it will help use dispose of the data. It all works in - a clean and efficient manner.</p> -<pre class=code> - <span class=codeComment><font color="#006600">// Bind buffer with a source.</font></span> - al.alGenSources(1, source); - - <span class=codeKeyword>if</span> (al.alGetError() != AL.AL_NO_ERROR) - <span class=codeKeyword>return</span> AL.AL_FALSE; - - 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_VELOCITY, sourceVel); - al.alSourcei (source[0], AL.AL_LOOPING, loop[0] );</pre> -<p>We generate a source object in the same manner we generated the buffer object. -Then we define the source properties that it will use when it's in playback. The -most important of these properties is the buffer it should use. This tells the -source which audio sample to playback. In this case we only have one so we bind -it. We also tell the source it's position and velocity which we defined earlier.</p> -<p>One more thing on 'alGenBuffers' and 'alGenSources'. In some example code I -have seen these functions will return an integer value for the number of -buffers/sources created. I suppose this was meant as an error checking feature -that was left out in a later version. If you see this done in other code don't -use it yourself. If you want to do this check, use 'alGetError' instead (like we -have done above).</p> -<pre class=code> - <span class=codeComment><font color="#006600">// Do another error check and return.</font></span> - <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_TRUE; - - <span class=codeKeyword><font color="#0000FF">return</font></span> AL.AL_FALSE; -} -</pre> -<p>To end the function we just do one more check to make sure all is well, then -we return success.</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); -} -</pre> -<p>We created this function to update the listener properties.</p> -<pre class=code><font color="#0000FF">static <span class=codeKeyword>void</span> </font>killALData() { - al.alDeleteBuffers(1, buffer); - al.alDeleteSources(1, source); - Alut.alutExit(); -} -</pre> - -<p>This will be our shutdown procedure. It is necessary to call this to release -all the memory and audio devices that our program may be using.</p> -<pre class=code><font color="#0000FF">public static void main</font>(<span class=codeKeyword>String[] args</span>) { - <span class=codeComment><font color="#006600">// Initialize OpenAL and clear the error bit.</font></span> -<span class=codeComment> - ALut.alutInit();</span> - al.alGetError(); - -</pre> -<p>The function 'alutInit' will setup everything that the Alc needs to do for -us. Basically Alut creates a single OpenAL context through Alc and sets it to -current. On the Windows platform it initializes DirectSound. We also do an -initial call to the error function to clear it. Every time we call 'glGetError' -it will reset itself to 'AL_NO_ERROR'.</p> -<pre class=code> -<span class=codeComment> <font color="#006600">// Load the wav data.</font></span> - <span class=codeKeyword><font color="#0000FF">if</font></span> (loadALData() == AL.AL_FALSE) - <span class=codeKeyword><font color="#0000FF">return</font></span> -1; - - setListenerValues(); - - <span class=codeComment><font color="#006600">// Setup an exit procedure.</font></span> - - Runtime runtime = Runtime.getRuntime(); - runtime.addShutdownHook( - <font color="#0000FF">new</font> Thread( - <font color="#0000FF">new</font> Runnable() { - <font color="#0000FF">public void</font> run() { - killAllData(); - } - } - ) - ); -</pre> -<p>We will check to see if the wav files loaded correctly. If not we must exit -the program. Then we update the listener values, and finally we set our exit -procedure.</p> -<pre class=code> <font color="#0000FF">char</font>[] c = new <font color="#0000FF">char</font>[1]; - <font color="#0000FF">while</font>(c[0] != 'q') { - <font color="#0000FF">try</font> { - BufferedReader buf = - <font color="#0000FF">new</font> BufferedReader(<font color="#0000FF">new</font> InputStreamReader(System.in)); - System.out.println("Press a key and hit ENTER: " + - "'p' to play, 's' to stop, 'h' to pause and 'q' to quit"); - buf.read(c); - <font color="#0000FF">switch</font>(c[0]) { - <font color="#0000FF">case</font> 'p': - <font color="#006600">// Pressing 'p' will begin playing the sample.</font> - al.alSourcePlay(source[0]); - <font color="#0000FF">break</font>; - <font color="#0000FF">case</font> 's': - <font color="#006600">// Pressing 's' will stop the sample from playing.</font> - alSourceStop(source[0]); - <font color="#0000FF">break</font>; - <font color="#0000FF">case</font> 'h': - <font color="#006600">// Pressing 'n' will pause (hold) the sample.</font> - alSourcePause(source[0]); - <font color="#0000FF">break</font>; - } - } <font color="#0000FF">catch</font> (IOException e) { - System.exit(1); - } - } -} - -</pre> -<p>This is the interesting part of the tutorial. It's a very basic loop that -lets us control the playback of the audio sample. Pressing 'p' will replay the -sample, pressing 's' will stop the sample, and pressing 'h' will pause the -sample. Pressing 'q' will exit the program.</p> -<p>Well there it is. Your first delve into OpenAL. I hope it was made simple -enough for you. It may have been a little too simple for the 1337 h4X0r, but we -all got to start somewhere. Things will get more advanced as we go along.</p> -<p> <a href="lesson1.zip">Download - the Java Source and Ant Build File</a></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> -<p> </p> -</body> -</html> |