Get emulator rendering working with Qt

include/PICA/gpu.hpp

@@ -86,10 +86,15 @@ class GPU {
 	bool lightingLUTDirty = false;
 
 	GPU(Memory& mem, EmulatorConfig& config);
-	void initGraphicsContext(SDL_Window* window) { renderer->initGraphicsContext(window); }
 	void display() { renderer->display(); }
 	void screenshot(const std::string& name) { renderer->screenshot(name); }
 
+#if defined(PANDA3DS_FRONTEND_SDL)
+	void initGraphicsContext(SDL_Window* window) { renderer->initGraphicsContext(window); }
+#elif defined(PANDA3DS_FRONTEND_QT)
+	void initGraphicsContext(GL::Context* context) { renderer->initGraphicsContext(context); }
+#endif
+
 	void fireDMA(u32 dest, u32 source, u32 size);
 	void reset();
 

include/emulator.hpp

@@ -20,6 +20,10 @@
 #include "http_server.hpp"
 #endif
 
+#ifdef PANDA3DS_FRONTEND_QT
+#include "gl/context.h"
+#endif
+
 enum class ROMType {
 	None,
 	ELF,
@@ -37,10 +41,12 @@ class Emulator {
 	Crypto::AESEngine aesEngine;
 	Cheats cheats;
 
+#ifdef PANDA3DS_FRONTEND_SDL
 	SDL_Window* window;
 
 #ifdef PANDA3DS_ENABLE_OPENGL
 	SDL_GLContext glContext;
+#endif
 #endif
 
 	SDL_GameController* gameController = nullptr;
@@ -106,5 +112,13 @@ class Emulator {
 	bool load3DSX(const std::filesystem::path& path);
 	bool loadELF(const std::filesystem::path& path);
 	bool loadELF(std::ifstream& file);
-	void initGraphicsContext();
+
+#ifdef PANDA3DS_FRONTEND_QT
+	// For passing the GL context from Qt to the renderer
+	void initGraphicsContext(GL::Context* glContext) { gpu.initGraphicsContext(nullptr); }
+#else
+	void initGraphicsContext() { gpu.initGraphicsContext(window); }
+#endif
+
+	EmulatorConfig& getConfig() { return config; }
 };

include/panda_qt/main_window.hpp

@@ -5,7 +5,9 @@
 #include <QMenuBar>
 #include <QPalette>
 #include <QtWidgets>
+#include <thread>
 
+#include "emulator.hpp"
 #include "panda_qt/screen.hpp"
 
 class MainWindow : public QMainWindow {
@@ -18,6 +20,10 @@ class MainWindow : public QMainWindow {
 		Dark = 2,
 	};
 
+	// This would normally be an std::unique_ptr but it's shared between threads so definitely not
+	Emulator* emu = nullptr;
+	std::thread emuThread;
+
 	QComboBox* themeSelect = nullptr;
 	QMenuBar* menuBar = nullptr;
 	ScreenWidget screen;

include/panda_qt/screen.hpp

@@ -11,6 +11,7 @@ class ScreenWidget : public QWidget {
 
   public:
 	ScreenWidget(QWidget* parent = nullptr);
+	GL::Context* getGLContext() { return glContext.get(); }
 
   private:
 	std::unique_ptr<GL::Context> glContext = nullptr;

include/renderer.hpp

@@ -7,6 +7,10 @@
 #include "PICA/regs.hpp"
 #include "helpers.hpp"
 
+#ifdef PANDA3DS_FRONTEND_QT
+#include "gl/context.h"
+#endif
+
 enum class RendererType : s8 {
 	// Todo: Auto = -1,
 	Null = 0,
@@ -50,10 +54,15 @@ class Renderer {
 	virtual void clearBuffer(u32 startAddress, u32 endAddress, u32 value, u32 control) = 0;  // Clear a GPU buffer in VRAM
 	virtual void displayTransfer(u32 inputAddr, u32 outputAddr, u32 inputSize, u32 outputSize, u32 flags) = 0;  // Perform display transfer
 	virtual void textureCopy(u32 inputAddr, u32 outputAddr, u32 totalBytes, u32 inputSize, u32 outputSize, u32 flags) = 0;
-	virtual void drawVertices(PICA::PrimType primType, std::span<const PICA::Vertex> vertices) = 0;             // Draw the given vertices
+	virtual void drawVertices(PICA::PrimType primType, std::span<const PICA::Vertex> vertices) = 0;  // Draw the given vertices
 
 	virtual void screenshot(const std::string& name) = 0;
 
+	// Functions for initializing the graphics context for the Qt frontend, where we don't have the convenience of SDL_Window
+#ifdef PANDA3DS_FRONTEND_QT
+	virtual void initGraphicsContext(GL::Context* context) { Helpers::panic("Tried to initialize incompatible renderer with GL context"); }
+#endif
+
 	void setFBSize(u32 width, u32 height) {
 		fbSize[0] = width;
 		fbSize[1] = height;

include/renderer_gl/renderer_gl.hpp

@@ -67,6 +67,7 @@ class RendererGL final : public Renderer {
 	void setupTextureEnvState();
 	void bindTexturesToSlots();
 	void updateLightingLUT();
+	void initGraphicsContextInternal();
 
   public:
 	RendererGL(GPU& gpu, const std::array<u32, regNum>& internalRegs, const std::array<u32, extRegNum>& externalRegs)
@@ -83,6 +84,10 @@ class RendererGL final : public Renderer {
 
 	std::optional<ColourBuffer> getColourBuffer(u32 addr, PICA::ColorFmt format, u32 width, u32 height, bool createIfnotFound = true);
 
+#ifdef PANDA3DS_FRONTEND_QT
+	virtual void initGraphicsContext([[maybe_unused]] GL::Context* context) override { initGraphicsContextInternal(); }
+#endif
+
 	// Take a screenshot of the screen and store it in a file
 	void screenshot(const std::string& name) override;
 };

include/renderer_null/renderer_null.hpp

@@ -15,4 +15,8 @@ class RendererNull final : public Renderer {
 	void textureCopy(u32 inputAddr, u32 outputAddr, u32 totalBytes, u32 inputSize, u32 outputSize, u32 flags) override;
 	void drawVertices(PICA::PrimType primType, std::span<const PICA::Vertex> vertices) override;
 	void screenshot(const std::string& name) override;
+
+#ifdef PANDA3DS_FRONTEND_QT
+	virtual void initGraphicsContext([[maybe_unused]] GL::Context* context) override {}
+#endif
 };

include/renderer_sw/renderer_sw.hpp

@@ -15,4 +15,8 @@ class RendererSw final : public Renderer {
 	void textureCopy(u32 inputAddr, u32 outputAddr, u32 totalBytes, u32 inputSize, u32 outputSize, u32 flags) override;
 	void drawVertices(PICA::PrimType primType, std::span<const PICA::Vertex> vertices) override;
 	void screenshot(const std::string& name) override;
+
+#ifdef PANDA3DS_FRONTEND_QT
+	virtual void initGraphicsContext([[maybe_unused]] GL::Context* context) override {}
+#endif
 };

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 || rendererType == RendererType::Null) {
+			// Make GL context current for this thread, enable VSync
+			GL::Context* glContext = screen.getGLContext();
+			glContext->MakeCurrent();
+			glContext->SetSwapInterval(1);
+
+			emu->initGraphicsContext(glContext);
+		} else {
+			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() {