Make emulator output size properly configurable

include/PICA/gpu.hpp

@@ -113,6 +113,9 @@ class GPU {
 	u32 readInternalReg(u32 index);
 	void writeInternalReg(u32 index, u32 value, u32 mask);
 
+	// Used for setting the size of the window we'll be outputting graphics to
+	void setOutputSize(u32 width, u32 height) { renderer->setOutputSize(width, height); }
+
 	// TODO: Emulate the transfer engine & its registers
 	// Then this can be emulated by just writing the appropriate values there
 	void clearBuffer(u32 startAddress, u32 endAddress, u32 value, u32 control) { renderer->clearBuffer(startAddress, endAddress, value, control); }

include/emulator.hpp

@@ -120,5 +120,7 @@ class Emulator {
 	void initGraphicsContext() { gpu.initGraphicsContext(window); }
 #endif
 
+	void setOutputSize(u32 width, u32 height) { gpu.setOutputSize(width, height); }
+
 	EmulatorConfig& getConfig() { return config; }
 };

include/panda_qt/screen.hpp

@@ -13,6 +13,10 @@ class ScreenWidget : public QWidget {
 	ScreenWidget(QWidget* parent = nullptr);
 	GL::Context* getGLContext() { return glContext.get(); }
 
+	// Dimensions of our output surface
+	u32 surfaceWidth = 0;
+	u32 surfaceHeight = 0;
+
   private:
 	std::unique_ptr<GL::Context> glContext = nullptr;
 	bool createGLContext();

include/renderer.hpp

@@ -40,6 +40,11 @@ class Renderer {
 	u32 depthBufferLoc;
 	PICA::DepthFmt depthBufferFormat;
 
+	// Width and height of the window we're outputting to, needed for properly scaling the final image
+	// We initialize it to the 3DS resolution by default and the frontend can notify us if it changes via the setOutputSize function
+	u32 outputWindowWidth = 400;
+	u32 outputWindowHeight = 240 * 2;
+
   public:
 	Renderer(GPU& gpu, const std::array<u32, regNum>& internalRegs, const std::array<u32, extRegNum>& externalRegs);
 	virtual ~Renderer();
@@ -78,4 +83,9 @@ class Renderer {
 
 	void setColourBufferLoc(u32 loc) { colourBufferLoc = loc; }
 	void setDepthBufferLoc(u32 loc) { depthBufferLoc = loc; }
+
+	void setOutputSize(u32 width, u32 height) {
+		outputWindowWidth = width;
+		outputWindowHeight = height;
+	}
 };

src/core/renderer_gl/renderer_gl.cpp

@@ -524,7 +524,7 @@ void RendererGL::display() {
 
 	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
 	screenFramebuffer.bind(OpenGL::ReadFramebuffer);
-	glBlitFramebuffer(0, 0, 400, 480, 0, 0, 400, 480, GL_COLOR_BUFFER_BIT, GL_LINEAR);
+	glBlitFramebuffer(0, 0, 400, 480, 0, 0, outputWindowWidth, outputWindowHeight, GL_COLOR_BUFFER_BIT, GL_LINEAR);
 }
 
 void RendererGL::clearBuffer(u32 startAddress, u32 endAddress, u32 value, u32 control) {

src/emulator.cpp

@@ -28,12 +28,6 @@ Emulator::Emulator()
 		Helpers::warn("Failed to initialize SDL2 GameController: %s", SDL_GetError());
 	}
 
-	// We need OpenGL for software rendering or for OpenGL if it's enabled
-	bool needOpenGL = config.rendererType == RendererType::Software;
-#ifdef PANDA3DS_ENABLE_OPENGL
-	needOpenGL = needOpenGL || (config.rendererType == RendererType::OpenGL);
-#endif
-
 #ifdef PANDA3DS_ENABLE_DISCORD_RPC
 	if (config.discordRpcEnabled) {
 		discordRpc.init();
@@ -41,6 +35,12 @@ Emulator::Emulator()
 	}
 #endif
 
+	// We need OpenGL for software rendering or for OpenGL if it's enabled
+	bool needOpenGL = config.rendererType == RendererType::Software;
+#ifdef PANDA3DS_ENABLE_OPENGL
+	needOpenGL = needOpenGL || (config.rendererType == RendererType::OpenGL);
+#endif
+
 	// Only create SDL Window for SDL frontend
 #ifdef PANDA3DS_FRONTEND_SDL
 	if (needOpenGL) {

src/panda_qt/main_window.cpp

@@ -27,6 +27,7 @@ MainWindow::MainWindow(QApplication* app, QWidget* parent) : QMainWindow(parent)
 	connect(themeSelect, &QComboBox::currentIndexChanged, this, [&](int index) { setTheme(static_cast<Theme>(index)); });
 
 	emu = new Emulator();
+	emu->setOutputSize(screen.surfaceWidth, screen.surfaceHeight);
 
 	// The emulator graphics context for the thread should be initialized in the emulator thread due to how GL contexts work 
 	emuThread = std::thread([&]() {

src/panda_qt/screen.cpp

@@ -105,6 +105,9 @@ std::optional<WindowInfo> ScreenWidget::getWindowInfo() {
 	wi.surface_height = static_cast<u32>(scaledWindowHeight());
 	wi.surface_scale = static_cast<float>(devicePixelRatioFromScreen());
 
+	surfaceWidth = wi.surface_width;
+	surfaceHeight = wi.surface_height;
+
 	return wi;
 }
 #endif