Added new audio device functions to set/get the audio device

drivers/alsa/audio_driver_alsa.cpp

@@ -37,19 +37,20 @@
 
 #include <errno.h>
 
-Error AudioDriverALSA::init() {
-
-	active = false;
-	thread_exited = false;
-	exit_thread = false;
-	pcm_open = false;
-	samples_in = NULL;
-	samples_out = NULL;
-
+Error AudioDriverALSA::init_device() {
 	mix_rate = GLOBAL_DEF("audio/mix_rate", DEFAULT_MIX_RATE);
 	speaker_mode = SPEAKER_MODE_STEREO;
 	channels = 2;
 
+	// If there is a specified device check that it is really present
+	if (device_name != "Default") {
+		Array list = get_device_list();
+		if (list.find(device_name) == -1) {
+			device_name = "Default";
+			new_device = "Default";
+		}
+	}
+
 	int status;
 	snd_pcm_hw_params_t *hwparams;
 	snd_pcm_sw_params_t *swparams;
@@ -65,7 +66,16 @@ Error AudioDriverALSA::init() {
 	//6 chans - "plug:surround51"
 	//4 chans - "plug:surround40";
 
-	status = snd_pcm_open(&pcm_handle, "default", SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
+	if (device_name == "Default") {
+		status = snd_pcm_open(&pcm_handle, "default", SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
+	} else {
+		String device = device_name;
+		int pos = device.find(";");
+		if (pos != -1) {
+			device = device.substr(0, pos);
+		}
+		status = snd_pcm_open(&pcm_handle, device.utf8().get_data(), SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
+	}
 
 	ERR_FAIL_COND_V(status < 0, ERR_CANT_OPEN);
 
@@ -129,15 +139,28 @@ Error AudioDriverALSA::init() {
 	status = snd_pcm_sw_params(pcm_handle, swparams);
 	CHECK_FAIL(status < 0);
 
-	samples_in = memnew_arr(int32_t, period_size * channels);
-	samples_out = memnew_arr(int16_t, period_size * channels);
+	samples_in.resize(period_size * channels);
+	samples_out.resize(period_size * channels);
 
 	snd_pcm_nonblock(pcm_handle, 0);
 
-	mutex = Mutex::create();
-	thread = Thread::create(AudioDriverALSA::thread_func, this);
-
 	return OK;
+}
+
+Error AudioDriverALSA::init() {
+
+	active = false;
+	thread_exited = false;
+	exit_thread = false;
+	pcm_open = false;
+
+	Error err = init_device();
+	if (err == OK) {
+		mutex = Mutex::create();
+		thread = Thread::create(AudioDriverALSA::thread_func, this);
+	}
+
+	return err;
 };
 
 void AudioDriverALSA::thread_func(void *p_udata) {
@@ -152,7 +175,7 @@ void AudioDriverALSA::thread_func(void *p_udata) {
 		} else {
 			ad->lock();
 
-			ad->audio_server_process(ad->period_size, ad->samples_in);
+			ad->audio_server_process(ad->period_size, ad->samples_in.ptrw());
 
 			ad->unlock();
 
@@ -167,7 +190,7 @@ void AudioDriverALSA::thread_func(void *p_udata) {
 		while (todo) {
 			if (ad->exit_thread)
 				break;
-			uint8_t *src = (uint8_t *)ad->samples_out;
+			uint8_t *src = (uint8_t *)ad->samples_out.ptr();
 			int wrote = snd_pcm_writei(ad->pcm_handle, (void *)(src + (total * ad->channels)), todo);
 
 			if (wrote < 0) {
@@ -193,6 +216,26 @@ void AudioDriverALSA::thread_func(void *p_udata) {
 			total += wrote;
 			todo -= wrote;
 		};
+
+		// User selected a new device, finish the current one so we'll init the new device
+		if (ad->device_name != ad->new_device) {
+			ad->device_name = ad->new_device;
+			ad->finish_device();
+
+			Error err = ad->init_device();
+			if (err != OK) {
+				ERR_PRINT("ALSA: init_device error");
+				ad->device_name = "Default";
+				ad->new_device = "Default";
+
+				err = ad->init_device();
+				if (err != OK) {
+					ad->active = false;
+					ad->exit_thread = true;
+					break;
+				}
+			}
+		}
 	};
 
 	ad->thread_exited = true;
@@ -213,6 +256,49 @@ AudioDriver::SpeakerMode AudioDriverALSA::get_speaker_mode() const {
 	return speaker_mode;
 };
 
+Array AudioDriverALSA::get_device_list() {
+
+	Array list;
+
+	list.push_back("Default");
+
+	void **hints;
+
+	if (snd_device_name_hint(-1, "pcm", &hints) < 0)
+		return list;
+
+	for (void **n = hints; *n != NULL; n++) {
+		char *name = snd_device_name_get_hint(*n, "NAME");
+		char *desc = snd_device_name_get_hint(*n, "DESC");
+
+		if (name != NULL && !strncmp(name, "plughw", 6)) {
+			if (desc) {
+				list.push_back(String(name) + ";" + String(desc));
+			} else {
+				list.push_back(String(name));
+			}
+		}
+
+		if (desc != NULL)
+			free(desc);
+		if (name != NULL)
+			free(name);
+	}
+	snd_device_name_free_hint(hints);
+
+	return list;
+}
+
+String AudioDriverALSA::get_device() {
+
+	return device_name;
+}
+
+void AudioDriverALSA::set_device(String device) {
+
+	new_device = device;
+}
+
 void AudioDriverALSA::lock() {
 
 	if (!thread || !mutex)
@@ -227,6 +313,14 @@ void AudioDriverALSA::unlock() {
 	mutex->unlock();
 };
 
+void AudioDriverALSA::finish_device() {
+
+	if (pcm_open) {
+		snd_pcm_close(pcm_handle);
+		pcm_open = NULL;
+	}
+}
+
 void AudioDriverALSA::finish() {
 
 	if (!thread)
@@ -235,17 +329,13 @@ void AudioDriverALSA::finish() {
 	exit_thread = true;
 	Thread::wait_to_finish(thread);
 
-	if (pcm_open)
-		snd_pcm_close(pcm_handle);
-
-	if (samples_in) {
-		memdelete_arr(samples_in);
-		memdelete_arr(samples_out);
-	};
+	finish_device();
 
 	memdelete(thread);
-	if (mutex)
+	if (mutex) {
 		memdelete(mutex);
+		mutex = NULL;
+	}
 	thread = NULL;
 };
 
@@ -254,6 +344,9 @@ AudioDriverALSA::AudioDriverALSA() {
 	mutex = NULL;
 	thread = NULL;
 	pcm_handle = NULL;
+
+	device_name = "Default";
+	new_device = "Default";
 };
 
 AudioDriverALSA::~AudioDriverALSA(){