Qt: Asynchronous drawing startup

src/platform/qt/Display.h

@@ -57,6 +57,7 @@ public:
 	std::shared_ptr<VideoProxy> videoProxy() { return m_videoProxy; }
 	
 signals:
+	void drawingStarted();
 	void showCursor();
 	void hideCursor();
 

src/platform/qt/DisplayGL.cpp

@@ -74,25 +74,32 @@ void DisplayGL::startDrawing(std::shared_ptr<CoreController> controller) {
 		videoProxy()->moveToThread(m_drawThread);
 	}
 	connect(m_drawThread, &QThread::started, m_painter.get(), &PainterGL::start);
-	m_drawThread->start();
+	connect(m_painter.get(), &PainterGL::started, this, [this] {
+		m_hasStarted = true;
+		resizePainter();
+		emit drawingStarted();
+	});
 
 	lockAspectRatio(isAspectRatioLocked());
 	lockIntegerScaling(isIntegerScalingLocked());
 	interframeBlending(hasInterframeBlending());
 	showOSDMessages(isShowOSD());
 	filter(isFiltered());
+
+	m_drawThread->start();
+
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
 	messagePainter()->resize(size(), isAspectRatioLocked(), devicePixelRatioF());
 #else
 	messagePainter()->resize(size(), isAspectRatioLocked(), devicePixelRatio());
 #endif
-	resizePainter();
 	setUpdatesEnabled(false);
 }
 
 void DisplayGL::stopDrawing() {
 	if (m_drawThread) {
 		m_isDrawing = false;
+		m_hasStarted = false;
 		CoreController::Interrupter interrupter(m_context);
 		QMetaObject::invokeMethod(m_painter.get(), "stop", Qt::BlockingQueuedConnection);
 		m_drawThread->exit();
@@ -187,18 +194,16 @@ void DisplayGL::clearShaders() {
 
 void DisplayGL::resizeContext() {
 	if (m_drawThread) {
-		m_isDrawing = false;
 		CoreController::Interrupter interrupter(m_context);
-		QMetaObject::invokeMethod(m_painter.get(), "resizeContext", Qt::BlockingQueuedConnection);
+		QMetaObject::invokeMethod(m_painter.get(), "resizeContext");
 	}
 }
 
 void DisplayGL::setVideoScale(int scale) {
 	if (m_drawThread) {
-		m_isDrawing = false;
 		CoreController::Interrupter interrupter(m_context);
 		mCoreConfigSetIntValue(&m_context->thread()->core->config, "videoScale", scale);
-		QMetaObject::invokeMethod(m_painter.get(), "resizeContext", Qt::BlockingQueuedConnection);
+		QMetaObject::invokeMethod(m_painter.get(), "resizeContext");
 	}
 }
 
@@ -208,7 +213,7 @@ void DisplayGL::resizeEvent(QResizeEvent* event) {
 }
 
 void DisplayGL::resizePainter() {
-	if (m_drawThread) {
+	if (m_drawThread && m_hasStarted) {
 		QMetaObject::invokeMethod(m_painter.get(), "resize", Qt::BlockingQueuedConnection, Q_ARG(QSize, size()));
 	}
 }
@@ -240,15 +245,19 @@ PainterGL::~PainterGL() {
 	}
 }
 
-void PainterGL::create() {
+void PainterGL::makeCurrent() {
-	m_gl = std::make_unique<QOpenGLContext>();
-	m_gl->setFormat(m_format);
-	m_gl->create();
-
 	m_gl->makeCurrent(m_surface);
 #if defined(_WIN32) && defined(USE_EPOXY)
 	epoxy_handle_external_wglMakeCurrent();
 #endif
+}
+
+void PainterGL::create() {
+	m_gl = std::make_unique<QOpenGLContext>();
+	m_gl->setFormat(m_format);
+	m_gl->create();
+	makeCurrent();
+
 	auto version = m_gl->format().version();
 	QStringList extensions = QString(reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS))).split(' ');
 
@@ -261,10 +270,11 @@ void PainterGL::create() {
 		QSurfaceFormat newFormat(m_format);
 		newFormat.setVersion(1, 4);
 		forceVersion = 1;
+		m_gl->doneCurrent();
 		m_gl->setFormat(newFormat);
 		m_gl->create();
+		makeCurrent();
 	}
-	m_gl->makeCurrent(m_surface);
 
 #ifdef BUILD_GL
 	mGLContext* glBackend;
@@ -274,9 +284,6 @@ void PainterGL::create() {
 #endif
 
 	m_window = std::make_unique<QOpenGLPaintDevice>();
-#if defined(_WIN32) && defined(USE_EPOXY)
-	epoxy_handle_external_wglMakeCurrent();
-#endif
 
 #ifdef BUILD_GLES2
 	version = m_gl->format().version();
@@ -303,10 +310,7 @@ void PainterGL::create() {
 			return;
 		}
 		painter->m_gl->swapBuffers(painter->m_surface);
-		painter->m_gl->makeCurrent(painter->m_surface);
+		painter->makeCurrent();
-#if defined(_WIN32) && defined(USE_EPOXY)
-		epoxy_handle_external_wglMakeCurrent();
-#endif
 	};
 
 	m_backend->init(m_backend, 0);
@@ -326,10 +330,7 @@ void PainterGL::destroy() {
 	if (!m_gl) {
 		return;
 	}
-	m_gl->makeCurrent(m_surface);
+	makeCurrent();
-#if defined(_WIN32) && defined(USE_EPOXY)
-	epoxy_handle_external_wglMakeCurrent();
-#endif
 	if (m_context) {
 		if (m_videoProxy) {
 			m_videoProxy->detach(m_context.get());
@@ -412,10 +413,7 @@ void PainterGL::start() {
 	if (!m_gl) {
 		create();
 	}
-	m_gl->makeCurrent(m_surface);
+	makeCurrent();
-#if defined(_WIN32) && defined(USE_EPOXY)
-	epoxy_handle_external_wglMakeCurrent();
-#endif
 
 #ifdef BUILD_GLES2
 	if (m_supportsShaders && m_shader.passes) {
@@ -427,6 +425,7 @@ void PainterGL::start() {
 	m_buffer = nullptr;
 	m_active = true;
 	m_started = true;
+	emit started();
 }
 
 void PainterGL::draw() {
@@ -559,21 +558,14 @@ void PainterGL::setShaders(struct VDir* dir) {
 	}
 #ifdef BUILD_GLES2
 	if (!m_started) {
-		m_gl->makeCurrent(m_surface);
+		return; // TODO
-#if defined(_WIN32) && defined(USE_EPOXY)
-		epoxy_handle_external_wglMakeCurrent();
-#endif
 	}
 	if (m_shader.passes) {
 		mGLES2ShaderDetach(reinterpret_cast<mGLES2Context*>(m_backend));
 		mGLES2ShaderFree(&m_shader);
 	}
 	mGLES2ShaderLoad(&m_shader, dir);
-	if (m_started) {
+	mGLES2ShaderAttach(reinterpret_cast<mGLES2Context*>(m_backend), static_cast<mGLES2Shader*>(m_shader.passes), m_shader.nPasses);
-		mGLES2ShaderAttach(reinterpret_cast<mGLES2Context*>(m_backend), static_cast<mGLES2Shader*>(m_shader.passes), m_shader.nPasses);
-	} else {
-		m_gl->doneCurrent();
-	}
 #endif
 }
 
@@ -583,18 +575,12 @@ void PainterGL::clearShaders() {
 	}
 #ifdef BUILD_GLES2
 	if (!m_started) {
-		m_gl->makeCurrent(m_surface);
+		return; // TODO
-#if defined(_WIN32) && defined(USE_EPOXY)
-		epoxy_handle_external_wglMakeCurrent();
-#endif
 	}
 	if (m_shader.passes) {
 		mGLES2ShaderDetach(reinterpret_cast<mGLES2Context*>(m_backend));
 		mGLES2ShaderFree(&m_shader);
 	}
-	if (!m_started) {
-		m_gl->doneCurrent();
-	}
 #endif
 }
 

src/platform/qt/DisplayGL.h

@@ -74,6 +74,7 @@ private:
 	void resizePainter();
 
 	bool m_isDrawing = false;
+	bool m_hasStarted = false;
 	std::unique_ptr<PainterGL> m_painter;
 	QThread* m_drawThread = nullptr;
 	std::shared_ptr<CoreController> m_context;
@@ -115,7 +116,11 @@ public slots:
 
 	int glTex();
 
+signals:
+	void started();
+
 private:
+	void makeCurrent();
 	void performDraw();
 	void dequeue();
 	void dequeueAll();

src/platform/qt/DisplayQt.cpp

@@ -28,6 +28,7 @@ void DisplayQt::startDrawing(std::shared_ptr<CoreController> controller) {
 	m_oldBacking = std::move(QImage());
 	m_isDrawing = true;
 	m_context = controller;
+	emit drawingStarted();
 }
 
 void DisplayQt::stopDrawing() {

src/platform/qt/Window.cpp

@@ -831,7 +831,6 @@ void Window::gameStopped() {
 	m_controller.reset();
 	updateTitle();
 
-	m_display->setVideoProxy({});
 	if (m_pendingClose) {
 		m_display.reset();
 		close();
@@ -919,7 +918,6 @@ void Window::reloadDisplayDriver() {
 		attachDisplay();
 
 		attachWidget(m_display.get());
-		m_display->startDrawing(m_controller);
 	}
 #ifdef M_CORE_GB
 	m_display->setMinimumSize(GB_VIDEO_HORIZONTAL_PIXELS, GB_VIDEO_VERTICAL_PIXELS);
@@ -964,6 +962,7 @@ void Window::changeRenderer() {
 		int fb = m_display->framebufferHandle();
 		if (fb >= 0) {
 			m_controller->setFramebufferHandle(fb);
+			m_config->updateOption("videoScale");
 		}
 	} else {
 		m_controller->setFramebufferHandle(-1);
@@ -1828,7 +1827,6 @@ void Window::setController(CoreController* controller, const QString& fname) {
 	m_inputController.recalibrateAxes();
 	m_controller->setInputController(&m_inputController);
 	m_controller->setLogger(&m_log);
-	m_display->startDrawing(m_controller);
 
 	connect(this, &Window::shutdown, [this]() {
 		if (!m_controller) {
@@ -1862,9 +1860,6 @@ void Window::setController(CoreController* controller, const QString& fname) {
 	connect(m_controller.get(), &CoreController::unpaused, [this]() {
 		emit paused(false);
 	});
-
-	attachDisplay();
-
 	connect(m_controller.get(), &CoreController::unpaused, &m_inputController, &InputController::suspendScreensaver);
 	connect(m_controller.get(), &CoreController::frameAvailable, this, &Window::recordFrame);
 	connect(m_controller.get(), &CoreController::crashed, this, &Window::gameCrashed);
@@ -1906,6 +1901,7 @@ void Window::setController(CoreController* controller, const QString& fname) {
 		m_pendingPatch = QString();
 	}
 
+	attachDisplay();
 	m_controller->loadConfig(m_config);
 	m_controller->start();
 
@@ -1929,7 +1925,8 @@ void Window::attachDisplay() {
 	connect(m_controller.get(), &CoreController::frameAvailable, m_display.get(), &Display::framePosted);
 	connect(m_controller.get(), &CoreController::statusPosted, m_display.get(), &Display::showMessage);
 	connect(m_controller.get(), &CoreController::didReset, m_display.get(), &Display::resizeContext);
-	changeRenderer();
+	connect(m_display.get(), &Display::drawingStarted, this, &Window::changeRenderer);
+	m_display->startDrawing(m_controller);
 }
 
 void Window::setLogo() {

src/platform/qt/Window.h

@@ -131,6 +131,7 @@ private slots:
 
 	void reloadAudioDriver();
 	void reloadDisplayDriver();
+	void attachDisplay();
 	void changeRenderer();
 
 	void tryMakePortable();
@@ -159,7 +160,6 @@ private:
 	void updateMRU();
 
 	void openView(QWidget* widget);
-	void attachDisplay();
 
 	template <typename T, typename... A> std::function<void()> openTView(A... arg);
 	template <typename T, typename... A> std::function<void()> openControllerTView(A... arg);