Start Android Audio Thread after audio buffer and AudioTrack are ready.

Also, it starts the Audio Thread from the native side, putting the code in line
with other backends.

android-project/src/org/libsdl/app/SDLActivity.java

@@ -252,8 +252,6 @@ public static native void onNativeTouch(int touchDevId, int pointerFingerId,
                                             int action, float x, 
                                             float y, float p);
     public static native void onNativeAccel(float x, float y, float z);
-    public static native void nativeRunAudioThread();
-
 
     // Java functions called from C
 
@@ -503,31 +501,15 @@ public static int audioInit(int sampleRate, boolean is16Bit, boolean isStereo, i
                 mAudioTrack = null;
                 return -1;
             }
+
+            mAudioTrack.play();
         }
-
-        audioStartThread();
-
+
         Log.v("SDL", "SDL audio: got " + ((mAudioTrack.getChannelCount() >= 2) ? "stereo" : "mono") + " " + ((mAudioTrack.getAudioFormat() == AudioFormat.ENCODING_PCM_16BIT) ? "16-bit" : "8-bit") + " " + (mAudioTrack.getSampleRate() / 1000f) + "kHz, " + desiredFrames + " frames buffer");
 
         return 0;
     }
 
-    public static void audioStartThread() {
-        if (mAudioThread == null) {
-            mAudioThread = new Thread(new Runnable() {
-                @Override
-                public void run() {
-                    mAudioTrack.play();
-                    nativeRunAudioThread();
-                }
-            });
-
-            // I'd take REALTIME if I could get it!
-            mAudioThread.setPriority(Thread.MAX_PRIORITY);
-            mAudioThread.start();
-        }
-    }
-
     public static void audioWriteShortBuffer(short[] buffer) {
         for (int i = 0; i < buffer.length; ) {
             int result = mAudioTrack.write(buffer, i, buffer.length - i);
@@ -565,17 +547,6 @@ public static void audioWriteByteBuffer(byte[] buffer) {
     }
 
     public static void audioQuit() {
-        if (mAudioThread != null) {
-            try {
-                mAudioThread.join();
-            } catch(Exception e) {
-                Log.v("SDL", "Problem stopping audio thread: " + e);
-            }
-            mAudioThread = null;
-
-            //Log.v("SDL", "Finished waiting for audio thread");
-        }
-
         if (mAudioTrack != null) {
             mAudioTrack.stop();
             mAudioTrack = null;
@@ -932,3 +903,4 @@ public boolean setComposingText(CharSequence text, int newCursorPosition) {
     public native void nativeSetComposingText(String text, int newCursorPosition);
 
 }
+

src/audio/android/SDL_androidaudio.c

@@ -50,7 +50,7 @@ AndroidAUD_OpenDevice(_THIS, const char *devname, int iscapture)
 
     audioDevice = this;
 
-    this->hidden = SDL_malloc(sizeof(*(this->hidden)));
+    this->hidden = (struct SDL_PrivateAudioData *) SDL_malloc(sizeof(*(this->hidden)));
     if (!this->hidden) {
         return SDL_OutOfMemory();
     }
@@ -91,6 +91,13 @@ AndroidAUD_OpenDevice(_THIS, const char *devname, int iscapture)
         /* Init failed? */
         return SDL_SetError("Java-side initialization failed!");
     }
+
+    /* Audio thread is started here, after audio buffers and Java's AudioTrack are in place and ready to go */
+    this->thread = SDL_CreateThread(SDL_RunAudio, "AndroidAudioThread", this);
+    if (this->thread == NULL) {
+        AndroidAUD_CloseDevice(this);
+        return SDL_SetError("Couldn't create audio thread");
+    }
 
     return 0;
 }
@@ -110,6 +117,10 @@ AndroidAUD_GetDeviceBuf(_THIS)
 static void
 AndroidAUD_CloseDevice(_THIS)
 {
+    /* At this point SDL_CloseAudioDevice via close_audio_device took care of terminating the audio thread
+       so it's safe to terminate the Java side buffer and AudioTrack
+     */
+
     if (this->hidden != NULL) {
         SDL_free(this->hidden);
         this->hidden = NULL;
@@ -143,13 +154,7 @@ AudioBootStrap ANDROIDAUD_bootstrap = {
     "android", "SDL Android audio driver", AndroidAUD_Init, 0
 };
 
-/* Called by the Java code to start the audio processing on a thread */
-void
-Android_RunAudioThread()
-{
-    SDL_RunAudio(audioDevice);
-}
-
 #endif /* SDL_AUDIO_DRIVER_ANDROID */
 
 /* vi: set ts=4 sw=4 expandtab: */
+

src/audio/android/SDL_androidaudio.h

@@ -32,6 +32,8 @@ struct SDL_PrivateAudioData
 {
 };
 
+static void AndroidAUD_CloseDevice(_THIS);
+
 #endif /* _SDL_androidaudio_h */
 
 /* vi: set ts=4 sw=4 expandtab: */

src/core/android/SDL_android.c

@@ -47,9 +47,6 @@
 /* Uncomment this to log messages entering and exiting methods in this file */
 //#define DEBUG_JNI
 
-/* Implemented in audio/android/SDL_androidaudio.c */
-extern void Android_RunAudioThread();
-
 static void Android_JNI_ThreadDestroyed(void*);
 
 /*******************************************************************************
@@ -245,15 +242,6 @@ void Java_org_libsdl_app_SDLActivity_nativeResume(
     }
 }
 
-void Java_org_libsdl_app_SDLActivity_nativeRunAudioThread(
-                                    JNIEnv* env, jclass cls)
-{
-    /* This is the audio thread, with a different environment */
-    Android_JNI_SetupThread();
-
-    Android_RunAudioThread();
-}
-
 void Java_org_libsdl_app_SDLInputConnection_nativeCommitText(
                                     JNIEnv* env, jclass cls,
                                     jstring text, jint newCursorPosition)
@@ -1374,3 +1362,4 @@ const char * SDL_AndroidGetExternalStoragePath()
 #endif /* __ANDROID__ */
 
 /* vi: set ts=4 sw=4 expandtab: */
+