godot/drivers/rtaudio/audio_driver_rtaudio.cpp

/*************************************************************************/
/*  audio_driver_rtaudio.cpp                                             */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
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#include "audio_driver_rtaudio.h"

#include "core/os/os.h"
#include "core/project_settings.h"

#ifdef RTAUDIO_ENABLED

const char *AudioDriverRtAudio::get_name() const {

#ifdef OSX_ENABLED
	return "RtAudio-OSX";
#elif defined(UNIX_ENABLED)
	return "RtAudio-ALSA";
#elif defined(WINDOWS_ENABLED)
	return "RtAudio-DirectSound";
#else
	return "RtAudio-None";
#endif
}

int AudioDriverRtAudio::callback(void *outputBuffer, void *inputBuffer, unsigned int nBufferFrames, double streamTime, RtAudioStreamStatus status, void *userData) {

	if (status) {
		if (status & RTAUDIO_INPUT_OVERFLOW) {
			WARN_PRINT("RtAudio input overflow!");
		}
		if (status & RTAUDIO_OUTPUT_UNDERFLOW) {
			WARN_PRINT("RtAudio output underflow!");
		}
	}
	int32_t *buffer = (int32_t *)outputBuffer;

	AudioDriverRtAudio *self = (AudioDriverRtAudio *)userData;

	if (self->mutex->try_lock() != OK) {
		// what should i do..
		for (unsigned int i = 0; i < nBufferFrames; i++)
			buffer[i] = 0;

		return 0;
	}

	self->audio_server_process(nBufferFrames, buffer);

	self->mutex->unlock();

	return 0;
}

Error AudioDriverRtAudio::init() {

	active = false;
	mutex = Mutex::create(true);
	dac = memnew(RtAudio);

	ERR_EXPLAIN("Cannot initialize RtAudio audio driver: No devices present.")
	ERR_FAIL_COND_V(dac->getDeviceCount() < 1, ERR_UNAVAILABLE);

	// FIXME: Adapt to the OutputFormat -> SpeakerMode change
	/*
	String channels = GLOBAL_DEF_RST("audio/output","stereo");

	if (channels=="5.1")
		output_format=OUTPUT_5_1;
	else if (channels=="quad")
		output_format=OUTPUT_QUAD;
	else if (channels=="mono")
		output_format=OUTPUT_MONO;
	else
		output_format=OUTPUT_STEREO;
	*/

	RtAudio::StreamParameters parameters;
	parameters.deviceId = dac->getDefaultOutputDevice();
	RtAudio::StreamOptions options;

	// set the desired numberOfBuffers
	options.numberOfBuffers = 4;

	parameters.firstChannel = 0;
	mix_rate = GLOBAL_DEF_RST("audio/mix_rate", DEFAULT_MIX_RATE);

	int latency = GLOBAL_DEF("audio/output_latency", DEFAULT_OUTPUT_LATENCY);
	unsigned int buffer_frames = closest_power_of_2(latency * mix_rate / 1000);
	print_verbose("Audio buffer frames: " + itos(buffer_frames) + " calculated latency: " + itos(buffer_frames * 1000 / mix_rate) + "ms");

	short int tries = 4;

	while (tries > 0) {
		switch (speaker_mode) {
			case SPEAKER_MODE_STEREO: parameters.nChannels = 2; break;
			case SPEAKER_SURROUND_31: parameters.nChannels = 4; break;
			case SPEAKER_SURROUND_51: parameters.nChannels = 6; break;
			case SPEAKER_SURROUND_71: parameters.nChannels = 8; break;
		};

		try {
			dac->openStream(&parameters, NULL, RTAUDIO_SINT32, mix_rate, &buffer_frames, &callback, this, &options);
			active = true;

			break;
		} catch (RtAudioError) {
			// try with less channels
			ERR_PRINT("Unable to open audio, retrying with fewer channels...");

			switch (speaker_mode) {
				case SPEAKER_MODE_STEREO: break; // Required to silence unhandled enum value warning.
				case SPEAKER_SURROUND_31: speaker_mode = SPEAKER_MODE_STEREO; break;
				case SPEAKER_SURROUND_51: speaker_mode = SPEAKER_SURROUND_31; break;
				case SPEAKER_SURROUND_71: speaker_mode = SPEAKER_SURROUND_51; break;
			}

			tries--;
		}
	}

	return active ? OK : ERR_UNAVAILABLE;
}

int AudioDriverRtAudio::get_mix_rate() const {

	return mix_rate;
}

AudioDriver::SpeakerMode AudioDriverRtAudio::get_speaker_mode() const {

	return speaker_mode;
}

void AudioDriverRtAudio::start() {

	if (active)
		dac->startStream();
}

void AudioDriverRtAudio::lock() {

	if (mutex)
		mutex->lock();
}

void AudioDriverRtAudio::unlock() {

	if (mutex)
		mutex->unlock();
}

void AudioDriverRtAudio::finish() {

	lock();
	if (active && dac->isStreamOpen()) {
		dac->closeStream();
		active = false;
	}
	unlock();

	if (mutex) {
		memdelete(mutex);
		mutex = NULL;
	}
	if (dac) {
		memdelete(dac);
		dac = NULL;
	}
}

AudioDriverRtAudio::AudioDriverRtAudio() :
		speaker_mode(SPEAKER_MODE_STEREO),
		mutex(NULL),
		dac(NULL),
		mix_rate(DEFAULT_MIX_RATE),
		active(false) {
}

#endif