Qt: Add screen resize

include/panda_qt/main_window.hpp

@@ -50,6 +50,7 @@ class MainWindow : public QMainWindow {
 		PressTouchscreen,
 		ReleaseTouchscreen,
 		ReloadUbershader,
+		SetScreenSize,
 	};
 
 	// Tagged union representing our message queue messages
@@ -81,6 +82,11 @@ class MainWindow : public QMainWindow {
 				u16 x;
 				u16 y;
 			} touchscreen;
+
+			struct {
+				u32 width;
+				u32 height;
+			} screenSize;
 		};
 	};
 
@@ -141,4 +147,6 @@ class MainWindow : public QMainWindow {
 	void loadLuaScript(const std::string& code);
 	void reloadShader(const std::string& shader);
 	void editCheat(u32 handle, const std::vector<uint8_t>& cheat, const std::function<void(u32)>& callback);
+
+	void handleScreenResize(u32 width, u32 height);
 };

include/panda_qt/screen.hpp

@@ -11,11 +11,20 @@ class ScreenWidget : public QWidget {
 
   public:
 	ScreenWidget(QWidget* parent = nullptr);
+	void resizeEvent(QResizeEvent* event) override;
+	// Called by the emulator thread for resizing the actual GL surface, since the emulator thread owns the GL context
+	void resizeSurface(u32 width, u32 height);
+
 	GL::Context* getGLContext() { return glContext.get(); }
 
 	// Dimensions of our output surface
 	u32 surfaceWidth = 0;
 	u32 surfaceHeight = 0;
+	WindowInfo windowInfo;
+
+	// Cached "previous" dimensions, used when resizing our window
+	u32 previousWidth = 0;
+	u32 previousHeight = 0;
 
   private:
 	std::unique_ptr<GL::Context> glContext = nullptr;

src/panda_qt/main_window.cpp

@@ -16,6 +16,7 @@ MainWindow::MainWindow(QApplication* app, QWidget* parent) : QMainWindow(parent)
 	// Enable drop events for loading ROMs
 	setAcceptDrops(true);
 	resize(800, 240 * 4);
+	setCentralWidget(&screen);
 	screen.show();
 
 	appRunning = true;
@@ -360,6 +361,15 @@ void MainWindow::dispatchMessage(const EmulatorMessage& message) {
 			emu->getRenderer()->setUbershader(*message.string.str);
 			delete message.string.str;
 			break;
+
+		case MessageType::SetScreenSize: {
+			const u32 width = message.screenSize.width;
+			const u32 height = message.screenSize.height;
+
+			emu->setOutputSize(width, height);
+			screen.resizeSurface(width, height);
+			break;
+		}
 	}
 }
 
@@ -482,6 +492,14 @@ void MainWindow::editCheat(u32 handle, const std::vector<uint8_t>& cheat, const
 	sendMessage(message);
 }
 
+void MainWindow::handleScreenResize(u32 width, u32 height) {
+	EmulatorMessage message{.type = MessageType::SetScreenSize};
+	message.screenSize.width = width;
+	message.screenSize.height = height;
+
+	sendMessage(message);
+}
+
 void MainWindow::initControllers() {
 	// Make SDL use consistent positional button mapping
 	SDL_SetHint(SDL_HINT_GAMECONTROLLER_USE_BUTTON_LABELS, "0");

src/panda_qt/screen.cpp

@@ -12,6 +12,7 @@
 #include <qpa/qplatformnativeinterface.h>
 #endif
 
+#include "panda_qt/main_window.hpp"
 #include "panda_qt/screen.hpp"
 
 // OpenGL screen widget, based on https://github.com/stenzek/duckstation/blob/master/src/duckstation-qt/displaywidget.cpp
@@ -35,6 +36,31 @@ ScreenWidget::ScreenWidget(QWidget* parent) : QWidget(parent) {
 	}
 }
 
+void ScreenWidget::resizeEvent(QResizeEvent* event) {
+	previousWidth = surfaceWidth;
+	previousHeight = surfaceHeight;
+
+	QWidget::resizeEvent(event);
+
+	// Update surfaceWidth/surfaceHeight following the resize
+	std::optional<WindowInfo> windowInfo = getWindowInfo();
+	if (windowInfo) {
+		this->windowInfo = *windowInfo;
+	}
+
+	// This will call take care of calling resizeSurface from the emulator thread
+	static_cast<MainWindow*>(parentWidget())->handleScreenResize(surfaceWidth, surfaceHeight);
+}
+
+// Note: This will run on the emulator thread, we don't want any Qt calls happening there.
+void ScreenWidget::resizeSurface(u32 width, u32 height) {
+	if (previousWidth != width || previousHeight != height) {
+		if (glContext) {
+			glContext->ResizeSurface(width, height);
+		}
+	}
+}
+
 bool ScreenWidget::createGLContext() {
 	// List of GL context versions we will try. Anything 4.1+ is good
 	static constexpr std::array<GL::Context::Version, 6> versionsToTry = {
@@ -45,6 +71,8 @@ bool ScreenWidget::createGLContext() {
 
 	std::optional<WindowInfo> windowInfo = getWindowInfo();
 	if (windowInfo.has_value()) {
+		this->windowInfo = *windowInfo;
+
 		glContext = GL::Context::Create(*getWindowInfo(), versionsToTry);
 		glContext->DoneCurrent();
 	}