cocos2dx 音频模块分析(5): 音效部分
我们上一篇中分析的音效部分的预加载和播放函数，这一篇来分析下其他函数： 1、 暂停某个播放中的音效 //注意这里的nSoundId不是java端的soundID，而是streamID //不要被参数的名字迷惑了。 void SimpleAudioEngine::pauseEffect(unsigned int nSoundId) { pauseEffectJNI(nSoundId); } -->> void pauseEffectJNI(unsigned int nSoundId) { // void pauseEffect(int) JniMethodInfo methodInfo; if (! getStaticMethodInfo(methodInfo,"pauseEffect","(I)V")) { return ; } methodInfo.env->CallStaticVoidMethod(methodInfo.classID,methodInfo.methodID,(int)nSoundId); methodInfo.env->DeleteLocalRef(methodInfo.classID); } ---->>//java端方法： //pStreamID 这个参数，是调用unsigned int SimpleAudioEngine::playEffect()放回的StreamID public void pauseEffect(final int pStreamID) { /** * Pause a playback stream. 暂停一个播放流 * * Pause the stream specified by the streamID. This is the * value returned by the play() function. (这个值是play函数的返回值)If the stream is * playing,it will be paused. If the stream is not playing * (e.g. is stopped or was prevIoUsly paused),calling this * function will have no effect.(如果处于播放状态则暂停，如果不处于播放状态，则无效) * * @param streamID a streamID returned by the play() function */ this.mSoundPool.pause(pStreamID); } 2、 暂停所有音效 void pauseAllEffectsJNI() { // void pauseAllEffects() JniMethodInfo methodInfo; if (! getStaticMethodInfo(methodInfo,"pauseAllEffects","()V")) { return ; } methodInfo.env->CallStaticVoidMethod(methodInfo.classID,methodInfo.methodID); methodInfo.env->DeleteLocalRef(methodInfo.classID); } --->>java端 public void pauseAllEffects() { /** * Pause all active streams. //暂停所有正在播放的音效 * * Pause all streams that are currently playing. This function * iterates through all the active streams and pauses any that * are playing. It also sets a flag so that any streams that * are playing can be resumed by calling autoResume(). */ this.mSoundPool.autoPause(); } 3、 恢复播放某个音效 void resumeEffectJNI(unsigned int nSoundId) { // void resumeEffect(int) JniMethodInfo methodInfo; if (! getStaticMethodInfo(methodInfo,"resumeEffect",(int)nSoundId); methodInfo.env->DeleteLocalRef(methodInfo.classID); } --->> public void resumeEffect(final int pStreamID) { /** * Resume a playback stream. * 只有处于暂停状态的stream，才可以恢复播放。 * Resume the stream specified by the streamID. This * is the value returned by the play() function. If the stream * is paused,this will resume playback. If the stream was not * prevIoUsly paused,calling this function will have no effect. * * @param streamID a streamID returned by the play() function */ this.mSoundPool.resume(pStreamID); } 4、 void resumeAllEffectsJNI() { // void resumeAllEffects() JniMethodInfo methodInfo; if (! getStaticMethodInfo(methodInfo,"resumeAllEffects",methodInfo.methodID); methodInfo.env->DeleteLocalRef(methodInfo.classID); } ---->>>java端函数： public void resumeAllEffects() { // can not only invoke SoundPool.autoResume() here,because // it only resumes all effects paused by pauseAllEffects() // 这里注释的很清楚 if (!this.mPathStreamIDsMap.isEmpty()) { final Iterator<Entry<String,ArrayList<Integer>>> iter = this.mPathStreamIDsMap.entrySet().iterator(); while (iter.hasNext()) { final Entry<String,ArrayList<Integer>> entry = iter.next(); for (final int pStreamID : entry.getValue()) { this.mSoundPool.resume(pStreamID); } } } } 5、 停止播放某个音效，这里的nSoundId同样是pStreamID，停止播放的音效是不能 通过resume恢复播放的。 void SimpleAudioEngine::stopEffect(unsigned int nSoundId) { stopEffectJNI(nSoundId); } --->>java端： public void stopEffect(final int pStreamID) { /** * Stop a playback stream. * * Stop the stream specified by the streamID. This * is the value returned by the play() function. If the stream * is playing,it will be stopped. It also releases any native * resources associated with this stream. (会释放对应的资源)If the stream is not * playing,it will have no effect. * * @param streamID a streamID returned by the play() function */ this.mSoundPool.stop(pStreamID); // remove record // 从记录列表中移除 for (final String pPath : this.mPathStreamIDsMap.keySet()) { if (this.mPathStreamIDsMap.get(pPath).contains(pStreamID)) { this.mPathStreamIDsMap.get(pPath).remove(this.mPathStreamIDsMap.get(pPath).indexOf(pStreamID)); break; } } } 6、 void stopAllEffectsJNI() { // void stopAllEffects() JniMethodInfo methodInfo; if (! getStaticMethodInfo(methodInfo,"stopAllEffects",methodInfo.methodID); methodInfo.env->DeleteLocalRef(methodInfo.classID); } --->>>java端 @SuppressWarnings("unchecked") public void stopAllEffects() { // stop effects，停止所有音效的播放 if (!this.mPathStreamIDsMap.isEmpty()) { final Iterator<?> iter = this.mPathStreamIDsMap.entrySet().iterator(); while (iter.hasNext()) { final Map.Entry<String,ArrayList<Integer>> entry = (Map.Entry<String,ArrayList<Integer>>) iter.next(); for (final int pStreamID : entry.getValue()) { this.mSoundPool.stop(pStreamID); } } } // remove records，清空播放记录 this.mPathStreamIDsMap.clear(); } 7、 卸载加载的音效(重要) //pszFilePath：音效文件名 void SimpleAudioEngine::unloadEffect(const char* pszFilePath) { std::string fullPath = getFullPathWithoutAssetsPrefix(pszFilePath); unloadEffectJNI(fullPath.c_str()); } --->> void unloadEffectJNI(const char* path) { // void unloadEffect(String) JniMethodInfo methodInfo; if (! getStaticMethodInfo(methodInfo,"unloadEffect","(Ljava/lang/String;)V")) { return ; } jstring stringArg = methodInfo.env->NewStringUTF(path); methodInfo.env->CallStaticVoidMethod(methodInfo.classID,stringArg); methodInfo.env->DeleteLocalRef(stringArg); methodInfo.env->DeleteLocalRef(methodInfo.classID); } --->>> public void unloadEffect(final String pPath) { // stop effects // 先停止 final ArrayList<Integer> streamIDs = this.mPathStreamIDsMap.get(pPath); if (streamIDs != null) { for (final Integer pStreamID : streamIDs) { this.mSoundPool.stop(pStreamID); } } this.mPathStreamIDsMap.remove(pPath); // unload effect final Integer soundID = this.mPathSoundIDMap.get(pPath); if(soundID != null){ /** * Unload a sound from a sound ID. * * Unloads the sound specified by the soundID. This is the value * returned by the load() function. Returns true if the sound is * successfully unloaded,false if the sound was already unloaded. * * @param soundID a soundID returned by the load() function * @return true if just unloaded,false if prevIoUsly unloaded */ // 卸载音效 this.mSoundPool.unload(soundID); // 从mPathSoundIDMap中移除 this.mPathSoundIDMap.remove(pPath); } } /************************************************ 总结: 音效部分最重要的函数是preloadEffect，unloadEffect，playEffect，stopAllEffects 其他的感觉不是很常用，java有两个比较重要的map，一个是： private final HashMap<String,Integer> mPathSoundIDMap = new HashMap<String,Integer>(); 这个是用来存放所有加载的音效文件路径和SoundID的map。 一个是： // sound path and stream ids map cocos2dx原本注释 // a file may be played many times at the same time // so there is an array map to a file path private final HashMap<String,ArrayList<Integer>> mPathStreamIDsMap = new HashMap<String,ArrayList<Integer>>(); 用来存放所有播放的音效文件路径和StreamIDs的map。 注意：这里的SoundID和StreamID不是一个概念，一个音效文件只对应一个SoundID，而却可以对应多个StreamID，因为一个 音效文件可以播放多次(StreamID)，但是只需要加载一次(SoundID). ************************************************/
