feat: 添加SDL2后端支持并实现基础示例程序

添加SDL2作为平台后端支持，包括窗口创建、输入处理和GLAD初始化
实现基础示例程序展示引擎基本功能
重构平台配置代码以提高可读性
移除未使用的input_codes.h头文件
添加demo_basic构建目标到xmake配置

Extra2D/include/extra2d/extra2d.h

@@ -48,7 +48,6 @@
 #include <extra2d/event/event.h>
 #include <extra2d/event/event_dispatcher.h>
 #include <extra2d/event/event_queue.h>
-#include <extra2d/event/input_codes.h>
 
 // Utils
 #include <extra2d/utils/logger.h>

Extra2D/include/extra2d/platform/platform_module.h

@@ -79,6 +79,7 @@ private:
  */
 #define E2D_REG_BACKEND(name, WinClass, InClass) \
     namespace { \
+        __attribute__((used)) \
         static struct E2D_BACKEND_REG_##name { \
             E2D_BACKEND_REG_##name() { \
                 ::extra2d::BackendFactory::reg( \

Extra2D/src/app/application.cpp

@@ -16,10 +16,18 @@
 #include <chrono>
 #include <thread>
 
+#include <SDL.h>
+
 #ifdef __SWITCH__
 #include <switch.h>
 #endif
 
+#ifdef E2D_BACKEND_SDL2
+namespace extra2d {
+void initSDL2Backend();
+}
+#endif
+
 namespace extra2d {
 
 /**
@@ -56,10 +64,16 @@ bool Application::init() {
 
 bool Application::init(const AppConfig& config) {
     if (initialized_) {
-        E2D_LOG_WARN("Application already initialized");
         return true;
     }
 
+    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS | SDL_INIT_TIMER) != 0) {
+        E2D_LOG_ERROR("Failed to initialize SDL: {}", SDL_GetError());
+        return false;
+    }
+
+    Logger::init();
+
     E2D_LOG_INFO("Initializing application with config...");
 
     if (!ConfigManager::instance().initialize()) {
@@ -92,6 +106,10 @@ bool Application::init(const std::string& configPath) {
 }
 
 bool Application::initImpl() {
+#ifdef E2D_BACKEND_SDL2
+    initSDL2Backend();
+#endif
+
     auto& configMgr = ConfigManager::instance();
     AppConfig& appConfig = configMgr.appConfig();
 

Extra2D/src/config/platform_config.cpp

@@ -1,5 +1,5 @@
-#include <extra2d/config/platform_config.h>
 #include <extra2d/config/app_config.h>
+#include <extra2d/config/platform_config.h>
 #include <extra2d/utils/logger.h>
 
 #ifdef _WIN32
@@ -43,10 +43,14 @@ public:
   const PlatformCapabilities &capabilities() const override { return caps_; }
 
   void applyConstraints(AppConfig &config) const override {
-        if (config.window.width < 320) config.window.width = 320;
-        if (config.window.height < 240) config.window.height = 240;
-        if (config.window.width > caps_.maxTextureSize) config.window.width = caps_.maxTextureSize;
-        if (config.window.height > caps_.maxTextureSize) config.window.height = caps_.maxTextureSize;
+    if (config.window.width < 320)
+      config.window.width = 320;
+    if (config.window.height < 240)
+      config.window.height = 240;
+    if (config.window.width > caps_.maxTextureSize)
+      config.window.width = caps_.maxTextureSize;
+    if (config.window.height > caps_.maxTextureSize)
+      config.window.height = caps_.maxTextureSize;
   }
 
   void applyDefaults(AppConfig &config) const override {
@@ -67,8 +71,8 @@ public:
   int getRecommendedWidth() const override { return 1920; }
   int getRecommendedHeight() const override { return 1080; }
   bool isResolutionSupported(int width, int height) const override {
-        return width >= 320 && height >= 240 &&
-               width <= caps_.maxTextureSize && height <= caps_.maxTextureSize;
+    return width >= 320 && height >= 240 && width <= caps_.maxTextureSize &&
+           height <= caps_.maxTextureSize;
   }
 
 private:
@@ -104,8 +108,10 @@ public:
   const PlatformCapabilities &capabilities() const override { return caps_; }
 
   void applyConstraints(AppConfig &config) const override {
-        if (config.window.width < 320) config.window.width = 320;
-        if (config.window.height < 240) config.window.height = 240;
+    if (config.window.width < 320)
+      config.window.width = 320;
+    if (config.window.height < 240)
+      config.window.height = 240;
   }
 
   void applyDefaults(AppConfig &config) const override {
@@ -160,8 +166,10 @@ public:
   const PlatformCapabilities &capabilities() const override { return caps_; }
 
   void applyConstraints(AppConfig &config) const override {
-        if (config.window.width < 320) config.window.width = 320;
-        if (config.window.height < 240) config.window.height = 240;
+    if (config.window.width < 320)
+      config.window.width = 320;
+    if (config.window.height < 240)
+      config.window.height = 240;
   }
 
   void applyDefaults(AppConfig &config) const override {
@@ -329,7 +337,7 @@ private:
 };
 #endif
 
-}
+} // namespace
 
 /**
  * @brief 创建平台配置实例
@@ -379,13 +387,19 @@ UniquePtr<PlatformConfig> createPlatformConfig(PlatformType type) {
  */
 const char *getPlatformTypeName(PlatformType type) {
   switch (type) {
-        case PlatformType::Auto:    return "Auto";
-        case PlatformType::Windows: return "Windows";
-        case PlatformType::Switch:  return "Switch";
-        case PlatformType::Linux:   return "Linux";
-        case PlatformType::macOS:   return "macOS";
-        default:                    return "Unknown";
+  case PlatformType::Auto:
+    return "Auto";
+  case PlatformType::Windows:
+    return "Windows";
+  case PlatformType::Switch:
+    return "Switch";
+  case PlatformType::Linux:
+    return "Linux";
+  case PlatformType::macOS:
+    return "macOS";
+  default:
+    return "Unknown";
   }
 }
 
-}
+} // namespace extra2d

Extra2D/src/platform/backends/sdl2/sdl2_backend.cpp

@@ -4,6 +4,25 @@
 
 namespace extra2d {
 
-E2D_REG_BACKEND(sdl2, SDL2Window, SDL2Input)
+namespace {
+    static bool s_sdl2BackendRegistered = false;
+}
+
+void initSDL2Backend() {
+    if (s_sdl2BackendRegistered) {
+        return;
+    }
+    s_sdl2BackendRegistered = true;
+    
+    BackendFactory::reg(
+        "sdl2",
+        []() -> UniquePtr<IWindow> { 
+            return makeUnique<SDL2Window>(); 
+        },
+        []() -> UniquePtr<IInput> { 
+            return makeUnique<SDL2Input>(); 
+        }
+    );
+}
 
 } // namespace extra2d

Extra2D/src/platform/backends/sdl2/sdl2_window.cpp

@@ -1,6 +1,7 @@
 #include "sdl2_window.h"
 #include "sdl2_input.h"
 #include <extra2d/utils/logger.h>
+#include <glad/glad.h>
 
 namespace extra2d {
 
@@ -73,6 +74,16 @@ bool SDL2Window::create(const WindowConfigData& cfg) {
         return false;
     }
 
+    if (!gladLoadGLES2Loader((GLADloadproc)SDL_GL_GetProcAddress)) {
+        E2D_LOG_ERROR("Failed to initialize GLAD");
+        SDL_GL_DeleteContext(glContext_);
+        glContext_ = nullptr;
+        SDL_DestroyWindow(sdlWindow_);
+        sdlWindow_ = nullptr;
+        deinitSDL();
+        return false;
+    }
+
     SDL_GL_SetSwapInterval(cfg.vsync ? 1 : 0);
 
     SDL_GetWindowSize(sdlWindow_, &width_, &height_);

examples/basic/main.cpp

@@ -0,0 +1,59 @@
+/**
+ * @file main.cpp
+ * @brief Extra2D 基础示例程序
+ * 
+ * 演示如何使用 Extra2D 引擎创建一个简单的窗口应用程序。
+ */
+
+#include <extra2d/extra2d.h>
+#include <iostream>
+
+using namespace extra2d;
+
+/**
+ * @brief 主函数
+ * 
+ * 初始化应用程序，创建场景，运行主循环。
+ */
+int main(int argc, char* argv[]) {
+    (void)argc;
+    (void)argv;
+
+    std::cout << "Extra2D Demo - Starting..." << std::endl;
+
+    AppConfig config = AppConfig::createDefault();
+    config.appName = "Extra2D Demo";
+    config.appVersion = "1.0.0";
+    config.window.title = "Extra2D Demo";
+    config.window.width = 800;
+    config.window.height = 600;
+    config.window.mode = WindowMode::Windowed;
+    config.window.resizable = true;
+    config.window.vsync = true;
+    config.render.targetFPS = 60;
+
+    Application& app = Application::get();
+
+    if (!app.init(config)) {
+        std::cerr << "Failed to initialize application!" << std::endl;
+        return -1;
+    }
+
+    std::cout << "Application initialized successfully!" << std::endl;
+    std::cout << "Window: " << app.window().width() << "x" << app.window().height() << std::endl;
+    std::cout << "Running main loop. Press ESC or close window to exit." << std::endl;
+
+    auto scene = Scene::create();
+    scene->setBackgroundColor(Colors::SkyBlue);
+    scene->setViewportSize(static_cast<float>(config.window.width),
+                           static_cast<float>(config.window.height));
+    app.enterScene(scene);
+
+    app.run();
+
+    std::cout << "Shutting down..." << std::endl;
+    app.shutdown();
+
+    std::cout << "Goodbye!" << std::endl;
+    return 0;
+}

xmake.lua

@@ -95,3 +95,23 @@ includes("xmake/engine.lua")
 -- 定义引擎库
 define_extra2d_engine()
 
+-- ==============================================
+-- 示例程序
+-- ==============================================
+
+-- 基础示例
+target("demo_basic")
+    set_kind("binary")
+    set_default(false)
+    
+    add_deps("extra2d")
+    add_files("examples/basic/main.cpp")
+    
+    -- 平台配置
+    local target_plat = get_config("plat") or os.host()
+    if target_plat == "mingw" then
+        add_packages("glm", "nlohmann_json", "libsdl2")
+        add_syslinks("opengl32", "glu32", "winmm", "imm32", "version", "setupapi")
+    end
+target_end()
+