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[Java-game-lib-cvs] CVS: LWJGL/doc/tutorial openal_basics.html,NONE,1.1
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From: Brian M. <ma...@us...> - 2002-09-05 15:46:24
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Update of /cvsroot/java-game-lib/LWJGL/doc/tutorial In directory usw-pr-cvs1:/tmp/cvs-serv22376 Added Files: openal_basics.html Log Message: renamed OpenAL_Tutoral to openal_basics --- NEW FILE: openal_basics.html --- CVS Browser: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/java-game-lib/LWJGL/doc/tutorial/openal_basics.html <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>OpenAL Tutoral</title> <meta http-equiv="content-type" content="text/html; charset=windows-1252"> <meta name="author" content="Brian Matzon"> <meta name="description" content="Basic sound using OpenAL"> </head> <body> <h1 align="center">OpenAL Tutorial<br> <font size="-1">(by Brian Matzon <<a href="mailto:br...@ma...">br...@ma...</a>>)</font><br> </h1> <b>1.0 OpenAL Basics</b><br> Before embarking on our little OpenAL adventure, some tools are needed.<br> <br> <b>1.0.1 Ingredients</b><br> Head on over to Creatives <a href="http://developer.creative.com/scripts/DC_D&H_Games-Downloads.asp?opt=2">site</a> and snag a copy of the OpenAL specification along with a copy of the Programmers reference.<br> If you haven't already done so, get a copy of the OpenAL runtime environment too (and install it).<br> <br> <b>1.1 OpenAL theory</b><br> Uhm... I'm not going to write this... In all honesty reading the specification would be a good thing before continuing - but it isn't required...<br> <br> <b>1.2 Basic setup</b><br> Lets start out by creating a skeleton class for some very basic sound. We'll start of by creating the required OpenAL objects<br> <p style="border-style: solid; border-width: 1px; padding: 3px; background-color: rgb(255,255,204);"><tt>import org.lwjgl.openal.AL;<br> import org.lwjgl.openal.ALC;<br> import org.lwjgl.openal.ALCcontext;<br> import org.lwjgl.openal.ALCdevice;<br> import org.lwjgl.openal.ALUT;<code></code><br> <br> public class PlayTest {<br> <br> /** OpenAL instance */<br> protected AL al;<br> <br> /** OpenAL Context instance */<br> protected ALC alc;<br> <br> /** OpenAL Util library instance */<br> protected ALUT alut;<br> <br> /** OpenAL context */<br> protected ALCcontext context;<br> <br> /** OpenAL device */<br> protected ALCdevice device; <br> <br> /**<br> * Creates an instance of PlayTest<br> */<br> public PlayTest() {<br> try {<br> </tt> <tt> al = new AL();<br> alc = new ALC();<br> alut = new ALUT();<br> <br> al.create();<br> alc.create();<br> alut.create();<br> } catch (Exception e) {<br> e.printStackTrace();<br> }</tt><tt><br> }<br> }</tt><code></code></p> We need instances of the following classes:<br> <ul> <li><tt>AL </tt>- basic source, buffer and listener interaction</li> <li><tt>ALC </tt>- context and device creatiuon</li> <li><tt>ALUT </tt>- OpenAL utility class</li> </ul> <b>1.3 OpenAL initialization</b><br> Now that we have created a basic class containing instances of the relevant OpenAL classes, lets start of by initializing OpenAL - that is create a device and a context:<br> <p style="border-style: solid; border-width: 1px; padding: 3px; background-color: rgb(255,255,204);"> <tt> /**<br> * Initializes OpenAL<br> */<br> protected void alInitialize() { <br> //get default device<br> device = alc.openDevice(null);<br> <br> //create context (no attributes specified)<br> context = alc.createContext(device, 0);<br> <br> //make context current<br> alc.makeContextCurrent(context);<br> }</tt><code><br> </code></p> Start of by opening a device using the <tt>openDevice </tt>method. <tt>openDevice </tt>takes a <tt>String </tt>as argument, containing the name of the device to open. If no name is supplied, the default device will be used (OpenAL currently doesn't support enumeration of devices available).<br> <br> Having opened a device, create a context to that device using <tt>createContext</tt>. <tt>createContext</tt> takes two arguments: device to use and a list of attributes (see specification for list of attributes). Since we're going by default context, we just specify <tt>0</tt> for attributes.<br> <br> Finish of by making the created context current. Do this by calling <tt>makeContextCurrent</tt>, supplying just created context as argument.<br> <p><b>1.4 Buffer and Source creation</b><br> Now that we have opened a device and gotten a context, we need to create two things to actually get some sound. We need to create a buffer to hold sounddata, and a source that is to play the sounddata.<br> Lets start of by creating one source, and one buffer:</p> <p style="border-style: solid; border-width: 1px; padding: 3px; background-color: rgb(255,255,204);"><tt> //create one IntBuffer as buffer and one as source<br> IntBuffer buffers = createIntBuffer(1);<br> IntBuffer sources = createIntBuffer(1);<br> <br> //generate buffers and sources<br> al.genBuffers(1, Sys.getDirectBufferAddress(buffers));<br> al.genSources(1, Sys.getDirectBufferAddress(sources));</tt></p> <p>There, all set for actually loading some sounddata into the buffer.<br> </p> <b>1.5 Loading sounddata and setting up a buffer</b><br> Now that we have a buffer, we need to load some sound data into this buffer. This is done using the <tt>al.bufferData</tt> method. In our example we will cheat a bit, by using the <tt>ALUT </tt>method <tt>loadWAVFile</tt> to load a wave file, and copy this into the buffer:<br> <p style="border-style: solid; border-width: 1px; padding: 3px; background-color: rgb(255,255,204);"><tt> //load wave data<br> ALUTLoadWAVData file = alut.loadWAVFile("myfile.wav");<br> <br> //copy to buffer<br> al.bufferData(buffers.get(0), file.format, file.data, file.size, file.freq);<br> <br> //unload file again<br> alut.unloadWAV(file.format, file.data, file.size, file.freq); <br> </tt></p> Having loaded the data, we pass it to <tt>bufferData</tt>. Once the buffer has been filled with sounddata, we unload it from the system using <tt>alut.unloadWAV</tt>. Don't worry about deleting it this soon - the sounddata has been <b>copied</b> to the buffer.<br> <br> <b>1.6 Associating sources and buffers</b><br> To associate a source to a buffer we set the integer BUFFER attribute on the source, and assign it a value of the buffer to play:<br> <p style="border-style: solid; border-width: 1px; padding: 3px; background-color: rgb(255,255,204);"><tt> //set up source input<br> al.sourcei(sources.get(0), AL.BUFFER, buffers.get(0));</tt><tt><br> </tt></p> <b>1.7 Setting source properties</b><br> Having set up the source, it is time to set some attributes on the source - there are many that can be set, but in this example we only set the looping attribute to true by doing the following:<br> <p style="border-style: solid; border-width: 1px; padding: 3px; background-color: rgb(255,255,204);"><tt> //loop source<br> al.sourcei(sources.get(0), AL.LOOPING, AL.TRUE);</tt><tt><br> </tt></p> <b>1.8 Sound...<br> </b>There, ready to play the sound, do this using the <tt>sourcePlay </tt>method of the <tt>AL </tt>class. to stop and pause use <tt>sourcePause </tt>and <tt>sourceStop </tt>respectively, and supply the source to affect:<br> <p style="border-style: solid; border-width: 1px; padding: 3px; background-color: rgb(255,255,204);"><tt> //play source 0<br> al.sourcePlay(sources.get(0));<br> <br> //wait 5 secs<br> try {<br> System.out.println("Waiting 5 seconds for sound to complete");<br> Thread.sleep(5000);<br> } catch (InterruptedException inte) {<br> }<br> <br> //stop source 0<br> al.sourceStop(sources.get(0));</tt></p> <b>1.9 Cleaning up<br> </b>Having had loads of fun playing a sound (!), it is now time to do some house chores. We need to clean up what we have created, this amounts to:<br> - deleting source and buffer<br> - deleting context<br> - closing devce<br> as is shown here:<b><br> </b> <p style="border-style: solid; border-width: 1px; padding: 3px; background-color: rgb(255,255,204);"><tt> //delete buffers and sources<br> al.deleteSources(1, Sys.getDirectBufferAddress(sources));<br> al.deleteBuffers(1, Sys.getDirectBufferAddress(buffers));<br> <br> //shutdown<br> alc.makeContextCurrent(null);<br> alc.destroyContext(context);<br> alc.closeDevice(device);</tt></p> There, all set. Now you should be able to play some basic sound!<br> This tutorial is rather short, and the above examples feature no error checking. For the complete source code, look at:<br> <tt>org.lwjgl.openal.BasicTest</tt> in the repository.<br> </body> </html> |
