Ability to resize internal sound buffers

src/gba/gba-audio.c

@@ -20,9 +20,9 @@ static int32_t _updateChannel4(struct GBAAudioChannel4* ch);
 static int _applyBias(struct GBAAudio* audio, int sample);
 static void _sample(struct GBAAudio* audio);
 
-void GBAAudioInit(struct GBAAudio* audio) {
-	CircleBufferInit(&audio->left, GBA_AUDIO_SAMPLES * sizeof(int32_t));
-	CircleBufferInit(&audio->right, GBA_AUDIO_SAMPLES * sizeof(int32_t));
+void GBAAudioInit(struct GBAAudio* audio, size_t samples) {
+	CircleBufferInit(&audio->left, samples * sizeof(int32_t));
+	CircleBufferInit(&audio->right, samples * sizeof(int32_t));
 	CircleBufferInit(&audio->chA.fifo, GBA_AUDIO_FIFO_SIZE);
 	CircleBufferInit(&audio->chB.fifo, GBA_AUDIO_FIFO_SIZE);
 }
@@ -70,6 +70,40 @@ void GBAAudioDeinit(struct GBAAudio* audio) {
 	CircleBufferDeinit(&audio->chB.fifo);
 }
 
+void GBAAudioResizeBuffer(struct GBAAudio* audio, size_t samples) {
+	if (samples >= GBA_AUDIO_SAMPLES) {
+		return;
+	}
+
+	GBASyncLockAudio(audio->p->sync);
+	int32_t buffer[GBA_AUDIO_SAMPLES];
+	int32_t dummy;
+	size_t read;
+	size_t i;
+
+	read = CircleBufferDump(&audio->left, buffer, sizeof(buffer));
+	CircleBufferDeinit(&audio->left);
+	CircleBufferInit(&audio->left, samples * sizeof(int32_t));
+	for (i = 0; i * sizeof(int32_t) < read; ++i) {
+		if (!CircleBufferWrite32(&audio->left, buffer[i])) {
+			CircleBufferRead32(&audio->left, &dummy);
+			CircleBufferWrite32(&audio->left, buffer[i]);
+		}
+	}
+
+	read = CircleBufferDump(&audio->right, buffer, sizeof(buffer));
+	CircleBufferDeinit(&audio->right);
+	CircleBufferInit(&audio->right, samples * sizeof(int32_t));
+	for (i = 0; i * sizeof(int32_t) < read; ++i) {
+		if (!CircleBufferWrite32(&audio->right, buffer[i])) {
+			CircleBufferRead32(&audio->right, &dummy);
+			CircleBufferWrite32(&audio->right, buffer[i]);
+		}
+	}
+
+	GBASyncUnlockAudio(audio->p->sync);
+}
+
 int32_t GBAAudioProcessEvents(struct GBAAudio* audio, int32_t cycles) {
 	audio->nextEvent -= cycles;
 	audio->eventDiff += cycles;
@@ -670,7 +704,7 @@ static void _sample(struct GBAAudio* audio) {
 	CircleBufferWrite32(&audio->left, sampleLeft);
 	CircleBufferWrite32(&audio->right, sampleRight);
 	unsigned produced = CircleBufferSize(&audio->left);
-	GBASyncProduceAudio(audio->p->sync, produced >= GBA_AUDIO_SAMPLES * 3);
+	GBASyncProduceAudio(audio->p->sync, produced >= CircleBufferCapacity(&audio->left) / sizeof(int32_t) * 3);
 }
 
 void GBAAudioSerialize(const struct GBAAudio* audio, struct GBASerializedState* state) {

src/gba/gba-audio.h

@@ -218,10 +218,12 @@ struct GBAStereoSample {
 	int16_t right;
 };
 
-void GBAAudioInit(struct GBAAudio* audio);
+void GBAAudioInit(struct GBAAudio* audio, size_t samples);
 void GBAAudioReset(struct GBAAudio* audio);
 void GBAAudioDeinit(struct GBAAudio* audio);
 
+void GBAAudioResizeBuffer(struct GBAAudio* audio, size_t samples);
+
 int32_t GBAAudioProcessEvents(struct GBAAudio* audio, int32_t cycles);
 void GBAAudioScheduleFifoDma(struct GBAAudio* audio, int number, struct GBADMA* info);
 

src/gba/gba-thread.c

@@ -86,6 +86,11 @@ static THREAD_ENTRY _GBAThreadRun(void* context) {
 #else
 	TlsSetValue(_contextKey, threadContext);
 #endif
+
+	if (threadContext->audioBuffers) {
+		GBAAudioResizeBuffer(&gba.audio, threadContext->audioBuffers);
+	}
+
 	if (threadContext->renderer) {
 		GBAVideoAssociateRenderer(&gba.video, threadContext->renderer);
 	}
@@ -551,6 +556,10 @@ void GBASyncLockAudio(struct GBASync* sync) {
 	MutexLock(&sync->audioBufferMutex);
 }
 
+void GBASyncUnlockAudio(struct GBASync* sync) {
+	MutexUnlock(&sync->audioBufferMutex);
+}
+
 void GBASyncConsumeAudio(struct GBASync* sync) {
 	ConditionWake(&sync->audioRequiredCond);
 	MutexUnlock(&sync->audioBufferMutex);

src/gba/gba-thread.h

@@ -57,6 +57,7 @@ struct GBAThread {
 	int activeKeys;
 	int frameskip;
 	float fpsTarget;
+	size_t audioBuffers;
 
 	// Threading state
 	Thread thread;
@@ -106,6 +107,7 @@ bool GBASyncDrawingFrame(struct GBASync* sync);
 
 void GBASyncProduceAudio(struct GBASync* sync, int wait);
 void GBASyncLockAudio(struct GBASync* sync);
+void GBASyncUnlockAudio(struct GBASync* sync);
 void GBASyncConsumeAudio(struct GBASync* sync);
 
 #endif

src/gba/gba.c

@@ -121,7 +121,7 @@ static void GBAInit(struct ARMCore* cpu, struct ARMComponent* component) {
 	GBAVideoInit(&gba->video);
 
 	gba->audio.p = gba;
-	GBAAudioInit(&gba->audio);
+	GBAAudioInit(&gba->audio, GBA_AUDIO_SAMPLES);
 
 	GBAIOInit(gba);