diff options
Diffstat (limited to 'www/devmaster/lesson5.html')
| -rw-r--r-- | www/devmaster/lesson5.html | 109 |
1 files changed, 55 insertions, 54 deletions
diff --git a/www/devmaster/lesson5.html b/www/devmaster/lesson5.html index 1fe183c..5eb3815 100644 --- a/www/devmaster/lesson5.html +++ b/www/devmaster/lesson5.html @@ -33,17 +33,17 @@ OpenAL Tutorials from DevMaster.net. Reprinted with Permission.<br> 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> +<p align="justify">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 align="justify">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"> @@ -64,13 +64,13 @@ OpenAL Tutorials from DevMaster.net. Reprinted with Permission.<br> 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> +<p align="justify">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; @@ -99,8 +99,8 @@ Vector sources = <font color="#0000FF">new </font>Vector(); <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 +<p align="justify">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() { @@ -121,16 +121,16 @@ Vector sources = <font color="#0000FF">new </font>Vector(); 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> +<p align="justify">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 align="justify">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]; @@ -176,8 +176,8 @@ Vector sources = <font color="#0000FF">new </font>Vector(); <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> +<p align="justify">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]; @@ -201,12 +201,12 @@ Vector sources = <font color="#0000FF">new </font>Vector(); } </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> +<p align="justify">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(); @@ -218,9 +218,9 @@ Vector sources = <font color="#0000FF">new </font>Vector(); 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> +<p align="justify">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') { @@ -248,19 +248,20 @@ Vector sources = <font color="#0000FF">new </font>Vector(); 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 align="justify">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 align="justify">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><a href="lesson5.zip">Download the Java Files and Ant build script</a></p> <table border="0" cellspacing="1" style="border-collapse: collapse" width="100%" id="AutoNumber2" bgcolor="#666699"> <tr> |