godot/servers/audio/audio_driver_dummy.cpp

/*************************************************************************/
/*  audio_driver_dummy.cpp                                               */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "audio_driver_dummy.h"

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

AudioDriverDummy *AudioDriverDummy::singleton = nullptr;

Error AudioDriverDummy::init() {
	active.clear();
	exit_thread.clear();
	samples_in = nullptr;

	if (mix_rate == -1) {
		mix_rate = GLOBAL_GET("audio/driver/mix_rate");
	}

	channels = get_channels();
	samples_in = memnew_arr(int32_t, (size_t)buffer_frames * channels);

	if (use_threads) {
		thread.start(AudioDriverDummy::thread_func, this);
	}

	return OK;
};

void AudioDriverDummy::thread_func(void *p_udata) {
	AudioDriverDummy *ad = static_cast<AudioDriverDummy *>(p_udata);

	uint64_t usdelay = (ad->buffer_frames / float(ad->mix_rate)) * 1000000;

	while (!ad->exit_thread.is_set()) {
		if (ad->active.is_set()) {
			ad->lock();
			ad->start_counting_ticks();

			ad->audio_server_process(ad->buffer_frames, ad->samples_in);

			ad->stop_counting_ticks();
			ad->unlock();
		};

		OS::get_singleton()->delay_usec(usdelay);
	};
};

void AudioDriverDummy::start() {
	active.set();
};

int AudioDriverDummy::get_mix_rate() const {
	return mix_rate;
};

AudioDriver::SpeakerMode AudioDriverDummy::get_speaker_mode() const {
	return speaker_mode;
};

void AudioDriverDummy::lock() {
	mutex.lock();
};

void AudioDriverDummy::unlock() {
	mutex.unlock();
};

void AudioDriverDummy::set_use_threads(bool p_use_threads) {
	use_threads = p_use_threads;
}

void AudioDriverDummy::set_speaker_mode(SpeakerMode p_mode) {
	speaker_mode = p_mode;
}

void AudioDriverDummy::set_mix_rate(int p_rate) {
	mix_rate = p_rate;
}

uint32_t AudioDriverDummy::get_channels() const {
	static const int channels_for_mode[4] = { 2, 4, 8, 16 };
	return channels_for_mode[speaker_mode];
}

void AudioDriverDummy::mix_audio(int p_frames, int32_t *p_buffer) {
	ERR_FAIL_COND(!active.is_set()); // If not active, should not mix.
	ERR_FAIL_COND(use_threads == true); // If using threads, this will not work well.

	uint32_t todo = p_frames;
	while (todo) {
		uint32_t to_mix = MIN(buffer_frames, todo);
		lock();
		audio_server_process(to_mix, samples_in);
		unlock();

		uint32_t total_samples = to_mix * channels;

		for (uint32_t i = 0; i < total_samples; i++) {
			p_buffer[i] = samples_in[i];
		}

		todo -= to_mix;
		p_buffer += total_samples;
	}
}

void AudioDriverDummy::finish() {
	if (use_threads) {
		exit_thread.set();
		thread.wait_to_finish();
	}

	if (samples_in) {
		memdelete_arr(samples_in);
	};
}

AudioDriverDummy::AudioDriverDummy() {
	singleton = this;
}