Audio rendering in Qt

src/platform/qt/AudioDevice.cpp

@@ -0,0 +1,33 @@
+#include "AudioDevice.h"
+
+extern "C" {
+#include "gba.h"
+#include "gba-audio.h"
+}
+
+using namespace QGBA;
+
+AudioDevice::AudioDevice(GBAAudio* audio, QObject* parent)
+	: QIODevice(parent)
+	, m_audio(audio)
+{
+	setOpenMode(ReadOnly);
+}
+
+void AudioDevice::setFormat(const QAudioFormat& format) {
+	// TODO: merge where the fudge rate exists
+	float fudgeRate = 16853760.0f / GBA_ARM7TDMI_FREQUENCY;
+	m_ratio = format.sampleRate() / (float) (m_audio->sampleRate * fudgeRate);
+}
+
+qint64 AudioDevice::readData(char* data, qint64 maxSize) {
+	if (maxSize > 0xFFFFFFFF) {
+		maxSize = 0xFFFFFFFF;
+	}
+
+	return GBAAudioResampleNN(m_audio, m_ratio, &m_drift, reinterpret_cast<GBAStereoSample*>(data), maxSize / sizeof(GBAStereoSample)) * sizeof(GBAStereoSample);
+}
+
+qint64 AudioDevice::writeData(const char*, qint64) {
+	return 0;
+}

src/platform/qt/AudioDevice.h

@@ -0,0 +1,31 @@
+#ifndef QGBA_AUDIO_DEVICE
+#define QGBA_AUDIO_DEVICE
+
+#include <QAudioFormat>
+#include <QIODevice>
+
+struct GBAAudio;
+
+namespace QGBA {
+
+class AudioDevice : public QIODevice {
+Q_OBJECT
+
+public:
+	AudioDevice(GBAAudio* audio, QObject* parent = 0);
+
+	void setFormat(const QAudioFormat& format);
+
+protected:
+	virtual qint64 readData(char* data, qint64 maxSize);
+	virtual qint64 writeData(const char* data, qint64 maxSize);
+
+private:
+	GBAAudio* m_audio;
+	float m_drift;
+	float m_ratio;
+};
+
+}
+
+#endif

src/platform/qt/CMakeLists.txt

@@ -14,11 +14,11 @@ set(CMAKE_INCLUDE_CURRENT_DIR ON)
 find_package(Qt5Widgets REQUIRED)
 
 set(UI_FILES Window.ui)
-set(SOURCE_FILES Display.cpp GameController.cpp Window.cpp)
+set(SOURCE_FILES AudioDevice.cpp Display.cpp GameController.cpp Window.cpp)
 
 qt5_wrap_ui(UI_HEADERS ${UI_FILES})
 
 add_executable(QGBAc WIN32 MACOSX_BUNDLE ${UI_FILES} ${UI_HEADERS} main.cpp ${SOURCE_FILES})
 
-qt5_use_modules(QGBAc Widgets OpenGL)
+qt5_use_modules(QGBAc Widgets Multimedia OpenGL)
 target_link_libraries(QGBAc ${OPENGL_LIBRARY} ${BINARY_NAME})

src/platform/qt/GameController.cpp

@@ -1,6 +1,7 @@
 #include "GameController.h"
 
 extern "C" {
+#include "gba.h"
 #include "renderers/video-software.h"
 }
 
@@ -9,6 +10,7 @@ using namespace QGBA;
 GameController::GameController(QObject* parent)
 	: QObject(parent)
 	, m_drawContext(256, 256, QImage::Format_RGB32)
+	, m_audioContext(0)
 {
 	m_renderer = new GBAVideoSoftwareRenderer;
 	GBAVideoSoftwareRendererCreate(m_renderer);
@@ -19,11 +21,14 @@ GameController::GameController(QObject* parent)
 	m_threadContext.renderer = &m_renderer->d;
 	m_threadContext.frameskip = 0;
 	m_threadContext.sync.videoFrameWait = 0;
-	m_threadContext.sync.audioWait = 0;
+	m_threadContext.sync.audioWait = 1;
-	m_threadContext.startCallback = 0;
+	m_threadContext.startCallback = [] (GBAThread* context) {
+		GameController* controller = static_cast<GameController*>(context->userData);
+		controller->setupAudio(&context->gba->audio);
+	};
 	m_threadContext.cleanCallback = 0;
 	m_threadContext.frameCallback = [] (GBAThread* context) {
-		GameController* controller = (GameController*) context->userData;
+		GameController* controller = static_cast<GameController*>(context->userData);
 		controller->frameAvailable(controller->m_drawContext);
 	};
 	m_threadContext.userData = this;
@@ -48,3 +53,12 @@ bool GameController::loadGame(const QString& path) {
 	GBAThreadStart(&m_threadContext);
 	return true;
 }
+
+void GameController::setupAudio(GBAAudio* audio) {
+	if (m_audioContext) {
+		delete m_audioContext;
+	}
+	m_audioContext = new AudioDevice(audio);
+
+	emit audioDeviceAvailable(m_audioContext);
+}

src/platform/qt/GameController.h

@@ -6,10 +6,13 @@
 #include <QObject>
 #include <QString>
 
+#include "AudioDevice.h"
+
 extern "C" {
 #include "gba-thread.h"
 }
 
+struct GBAAudio;
 struct GBAVideoSoftwareRenderer;
 
 namespace QGBA {
@@ -23,12 +26,16 @@ public:
 
 signals:
 	void frameAvailable(const QImage&);
+	void audioDeviceAvailable(AudioDevice*);
 
 public slots:
 	bool loadGame(const QString& path);
 
 private:
+	void setupAudio(GBAAudio* audio);
+
 	QImage m_drawContext;
+	AudioDevice* m_audioContext;
 	GBAThread m_threadContext;
 	GBAVideoSoftwareRenderer* m_renderer;
 

src/platform/qt/Window.cpp

@@ -11,6 +11,7 @@ Window::Window(QWidget* parent) : QMainWindow(parent) {
 	m_display = new Display(this);
 	setCentralWidget(m_display);
 	connect(m_controller, SIGNAL(frameAvailable(const QImage&)), m_display, SLOT(draw(const QImage&)));
+	connect(m_controller, SIGNAL(audioDeviceAvailable(AudioDevice*)), this, SLOT(setupAudio(AudioDevice*)));
 
 	connect(actionOpen, SIGNAL(triggered()), this, SLOT(selectROM()));
 }
@@ -21,3 +22,20 @@ void Window::selectROM() {
 		m_controller->loadGame(filename);
 	}
 }
+
+void Window::setupAudio(AudioDevice* device) {
+	if (!m_audio) {
+		QAudioFormat format;
+		format.setSampleRate(44100);
+		format.setChannelCount(2);
+		format.setSampleSize(16);
+		format.setCodec("audio/pcm");
+		format.setByteOrder(QAudioFormat::LittleEndian);
+		format.setSampleType(QAudioFormat::SignedInt);
+
+		m_audio = new QAudioOutput(format, this);
+		m_audio->setBufferSize(1024);
+	}
+	device->setFormat(m_audio->format());
+	m_audio->start(device);
+}

src/platform/qt/Window.h

@@ -1,6 +1,7 @@
 #ifndef QGBA_WINDOW
 #define QGBA_WINDOW
 
+#include <QAudioOutput>
 #include <QMainWindow>
 
 #include "GameController.h"
@@ -19,7 +20,11 @@ public:
 public slots:
 	void selectROM();
 
+private slots:
+	void setupAudio(AudioDevice*);
+
 private:
+	QAudioOutput* m_audio;
 	GameController* m_controller;
 	Display* m_display;
 };