Get emulator rendering working with Qt

src/core/renderer_gl/renderer_gl.cpp

@@ -46,7 +46,7 @@ void RendererGL::reset() {
 	}
 }
 
-void RendererGL::initGraphicsContext(SDL_Window* window) {
+void RendererGL::initGraphicsContextInternal() {
 	gl.reset();
 
 	auto gl_resources = cmrc::RendererGL::get_filesystem();
@@ -168,6 +168,10 @@ void RendererGL::initGraphicsContext(SDL_Window* window) {
 	reset();
 }
 
+// The OpenGL renderer doesn't need to do anything with the GL context (For Qt frontend) or the SDL window (For SDL frontend)
+// So we just call initGraphicsContextInternal for both
+void RendererGL::initGraphicsContext([[maybe_unused]] SDL_Window* window) { initGraphicsContextInternal(); }
+
 // Set up the OpenGL blending context to match the emulated PICA
 void RendererGL::setupBlending() {
 	// Map of PICA blending equations to OpenGL blending equations. The unused blending equations are equivalent to equation 0 (add)

src/emulator.cpp

@@ -41,6 +41,8 @@ Emulator::Emulator()
 	}
 #endif
 
+	// Only create SDL Window for SDL frontend
+#ifdef PANDA3DS_FRONTEND_SDL
 	if (needOpenGL) {
 		// Demand 3.3 core for software renderer, or 4.1 core for OpenGL renderer (max available on MacOS)
 		// MacOS gets mad if we don't explicitly demand a core profile
@@ -71,6 +73,7 @@ Emulator::Emulator()
 			Helpers::warn("Window creation failed: %s", SDL_GetError());
 		}
 	}
+#endif
 #endif
 
 	if (SDL_WasInit(SDL_INIT_GAMECONTROLLER)) {
@@ -126,6 +129,8 @@ void Emulator::reset(ReloadOption reload) {
 void Emulator::step() {}
 void Emulator::render() {}
 
+// Main loop for the SDL frontend. TODO: Move it to a dedicated file
+#ifdef PANDA3DS_FRONTEND_SDL
 void Emulator::run() {
 	programRunning = true;
 
@@ -403,6 +408,7 @@ void Emulator::run() {
 		SDL_GL_SwapWindow(window);
 	}
 }
+#endif
 
 // Only resume if a ROM is properly loaded
 void Emulator::resume() { running = (romType != ROMType::None); }
@@ -562,9 +568,6 @@ bool Emulator::loadELF(std::ifstream& file) {
 	return true;
 }
 
-// Reset our graphics context and initialize the GPU's graphics context
-void Emulator::initGraphicsContext() { gpu.initGraphicsContext(window); }
-
 #ifdef PANDA3DS_ENABLE_DISCORD_RPC
 void Emulator::updateDiscord() {
 	if (config.discordRpcEnabled) {

src/panda_qt/main_window.cpp

@@ -4,7 +4,7 @@ MainWindow::MainWindow(QApplication* app, QWidget* parent) : QMainWindow(parent)
 	setWindowTitle("Alber");
 	// Enable drop events for loading ROMs
 	setAcceptDrops(true);
-	resize(320, 240);
+	resize(400, 240 * 2);
 	screen.show();
 
 	// Set our menu bar up
@@ -25,9 +25,42 @@ MainWindow::MainWindow(QApplication* app, QWidget* parent) : QMainWindow(parent)
 	themeSelect->setGeometry(40, 40, 100, 50);
 	themeSelect->show();
 	connect(themeSelect, &QComboBox::currentIndexChanged, this, [&](int index) { setTheme(static_cast<Theme>(index)); });
+
+	emu = new Emulator();
+
+	// The emulator graphics context for the thread should be initialized in the emulator thread due to how GL contexts work 
+	emuThread = std::thread([&]() {
+		const RendererType rendererType = emu->getConfig().rendererType;
+
+		if (rendererType == RendererType::OpenGL || rendererType == RendererType::Software) {
+			// Make GL context current for this thread, enable VSync
+			GL::Context* glContext = screen.getGLContext();
+			glContext->MakeCurrent();
+			glContext->SetSwapInterval(1);
+
+			emu->initGraphicsContext(glContext);
+		} else if (rendererType != RendererType::Null) {
+			Helpers::panic("Unsupported renderer type for the Qt backend! Vulkan on Qt is currently WIP, try the SDL frontend instead!");
+		}
+
+		bool success = emu->loadROM("OoT.3ds");
+		if (!success) {
+			Helpers::panic("Failed to load ROM");
+		}
+
+		while (true) {
+			emu->runFrame();
+			screen.getGLContext()->SwapBuffers();
+		}
+	});
 }
 
-MainWindow::~MainWindow() { delete menuBar; }
+// Cleanup when the main window closes
+MainWindow::~MainWindow() {
+	delete emu;
+	delete menuBar;
+	delete themeSelect;
+}
 
 void MainWindow::setTheme(Theme theme) {
 	currentTheme = theme;

src/panda_qt/screen.cpp

@@ -20,7 +20,7 @@
 #ifdef PANDA3DS_ENABLE_OPENGL
 ScreenWidget::ScreenWidget(QWidget* parent) : QWidget(parent) {
 	// Create a native window for use with our graphics API of choice
-	resize(320, 240);
+	resize(400, 240 * 2);
 	
 	setAutoFillBackground(false);
 	setAttribute(Qt::WA_NativeWindow, true);
@@ -33,18 +33,6 @@ ScreenWidget::ScreenWidget(QWidget* parent) : QWidget(parent) {
 	if (!createGLContext()) {
 		Helpers::panic("Failed to create GL context for display");
 	}
-
-	// Make our context current to use it
-	glContext->MakeCurrent();
-	// Enable VSync for now
-	glContext->SetSwapInterval(1);
-
-	OpenGL::setViewport(320, 240);
-	OpenGL::setClearColor(1.0, 0.0, 0.0, 1.0);
-	OpenGL::clearColor();
-
-	// Swap buffers to display our red as a test
-	glContext->SwapBuffers();
 }
 
 bool ScreenWidget::createGLContext() {