lwjgl/src/java/org/lwjgl/openal/AL.java

/* 
 * Copyright (c) 2002 Lightweight Java Game Library Project
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are 
 * met:
 * 
 * * Redistributions of source code must retain the above copyright 
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'Lightweight Java Game Library' nor the names of 
 *   its contributors may be used to endorse or promote products derived 
 *   from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.lwjgl.openal;

import java.io.File;
import java.lang.reflect.Method;
import java.util.StringTokenizer;

import org.lwjgl.Display;
import org.lwjgl.Sys;

/**
 * $Id$
 * <br>
 * This is the OpenAL class. It extends the latest core.
 *
 * @author Brian Matzon <brian@matzon.dk>
 * @version $Revision$
 */
public abstract class AL {

	/** ALC instance. */
	protected static ALC alc;

	/** ALCdevice instance. */
	protected static ALCdevice device;

	/** Current ALCcontext. */
	protected static ALCcontext context;

	/** 
	 * String that requests a certain device or device configuration. 
	 * If null is specified, the implementation will provide an 
	 * implementation specific default. 
   */
	protected static String deviceArguments;

	/** Frequency for mixing output buffer, in units of Hz. */
	protected static int contextFrequency = -1;

	/** Refresh intervalls, in units of Hz. */
	protected static int contextRefresh = -1;

	/** Flag, indicating a synchronous context. */
	protected static int contextSynchronized = ALC.ALC_FALSE;

  /** Have we been created? */
  protected static boolean created;

  static {
    initialize();
  }

  /**
   * Static initialization
   */
  private static void initialize() {
    System.loadLibrary(org.lwjgl.Sys.getLibraryName());
  }

  /**
   * Native method to create AL instance
   * 
   * @param oalPaths Array of strings containing paths to search for OpenAL library
   * @return true if the AL creation process succeeded
   */
  protected static native void nCreate(String[] oalPaths) throws OpenALException;

  /**
   * Native method the destroy the AL
   */
  protected static native void nDestroy();
  
  /**
   * @return true if AL has been created
   */
  public static boolean isCreated() {
    return created;
  }  
  
	/**
	* Creates an OpenAL instance. Using this constructor will cause OpenAL to
	* open the device using supplied device argument, and create a context using the context values
	* supplied. 
	* 
	* @param deviceArguments Arguments supplied to native device
	* @param contextFrequency Frequency for mixing output buffer, in units of Hz (Common values include 11025, 22050, and 44100).
	* @param contextRefresh Refresh intervalls, in units of Hz.
	* @param contextSynchronized Flag, indicating a synchronous context.* 
	 */
	public static void create(String deviceArguments, int contextFrequency, int contextRefresh, boolean contextSynchronized)
		throws OpenALException {
      
	  if (created) {
		  return;
    }
      
      
		AL.deviceArguments = deviceArguments;
		AL.contextFrequency = contextFrequency;
		AL.contextRefresh = contextRefresh;
		AL.contextSynchronized = contextSynchronized ? ALC.ALC_TRUE : ALC.ALC_FALSE;

		create();
	}

	/**
	 * Creates an OpenAL instance. The empty create will cause OpenAL to
	 * open the default device, and create a context using default values. 
	 */
	public static void create() throws OpenALException {
    if(created) {
      return;
    }

    // need to pass path of possible locations of OAL to native side
    String libpath = System.getProperty("java.library.path");
    String seperator = System.getProperty("path.separator");
    String libname;
    String jwsLibname;

    // libname is hardcoded atm - this will change in a near future...
    switch (Display.getPlatform()) {
      case Display.PLATFORM_WGL:
        libname = "lwjglaudio.dll";
        jwsLibname = "lwjglaudio";
        break;
      case Display.PLATFORM_GLX:
        libname = "libopenal.so";
        jwsLibname = "openal";
        break;
      case Display.PLATFORM_AGL:
        libname = "openal.dylib";
        jwsLibname = "openal";
        break;
      default:
        throw new OpenALException("Unknown platform");
    }
    
    String jwsPath = getPathFromJWS(jwsLibname);
    if (jwsPath != null) {
      libpath += seperator
        + jwsPath.substring(0, jwsPath.lastIndexOf(File.separator));
    }

    StringTokenizer st = new StringTokenizer(libpath, seperator);

    //create needed string array
    String[] oalPaths = new String[st.countTokens() + 1];

    //build paths
    for (int i = 0; i < oalPaths.length - 1; i++) {
      oalPaths[i] = st.nextToken() + File.separator + libname;
    }

    //add cwd path
    oalPaths[oalPaths.length - 1] = libname;
    nCreate(oalPaths);

    ALC.create();

		device = ALC.alcOpenDevice(deviceArguments);

		//check if doing default values or not
		if (contextFrequency == -1) {
			context = ALC.alcCreateContext(device.device, null);
		} else {
			context =
				ALC.alcCreateContext(
					device.device,
					ALCcontext.createAttributeList(contextFrequency, contextRefresh, contextSynchronized));
		}

		ALC.alcMakeContextCurrent(context.context);

    created = true;
	}

	/**
	 * Exit cleanly by calling destroy.
	 */
	public static void destroy() {
    if(!created) {
      return;
    }
    
		ALC.alcDestroyContext(context.context);
		ALC.alcCloseDevice(device.device);
		ALC.destroy();

		device = null;
		context = null;

		deviceArguments = null;

		contextFrequency = -1;
		contextRefresh = -1;
		contextSynchronized = ALC.ALC_FALSE;
    
    created = false;
    nDestroy();    
	}
  
  /**
   * Tries to locate OpenAL from the JWS Library path
   * This method exists because OpenAL is loaded from native code, and as such
   * is exempt from JWS library loading rutines. OpenAL therefore always fails.
   * We therefore invoke the protected method of the JWS classloader to see if it can
   * locate it. 
   * 
   * @param libname Name of library to search for
   * @return Absolute path to library if found, otherwise null
   */
  private static String getPathFromJWS(String libname) {
    try {     

      Sys.log("JWS Classloader looking for: " + libname);
      
      Object o = AL.class.getClassLoader();
      Class c = o.getClass();
      Method findLibrary =
        c.getMethod("findLibrary", new Class[] { String.class });
      Object[] arguments = new Object[] { libname };
      return (String) findLibrary.invoke(o, arguments);

    } catch (Exception e) {
      Sys.log("Failure locating OpenAL using classloader:" + e);
    }
    return null;
  }  
}