.gitmodules

@@ -1,6 +1,7 @@
+[submodule "dependencies/imgui"]
+	path = dependencies/imgui
+	url = https://github.com/ocornut/imgui.git
+	branch = docking
 [submodule "dependencies/resource_embedder"]
 	path = dependencies/resource_embedder
 	url = https://timerix.ddns.net/git/Timerix/resource_embedder.git
-[submodule "dependencies/cimgui"]
-	path = dependencies/cimgui
-	url = https://github.com/cimgui/cimgui.git

.vscode/c_cpp_properties.json

@@ -9,7 +9,7 @@
             "includePath": [
                 "dependencies/include",
                 "dependencies/include/SDL2",
-                "dependencies/cimgui/imgui",
+                "dependencies/imgui",
                 "${default}"
             ],
             "cppStandard": "c++20"

README.md

@@ -4,7 +4,7 @@ A game engine or something, idk.
 ## Installation
 1. **Clone the repository.**
 ```sh
-git clone --recurse-submodules --depth 1 https://timerix.ddns.net/git/Timerix/ougge.git
+git clone --recurse-submodules https://timerix.ddns.net/git/Timerix/ougge.git
 ```
 2. **Install [cbuild](https://timerix.ddns.net/git/Timerix/cbuild).**
 3. **Install [SDL2](https://github.com/libsdl-org/SDL) and [SDL2_image](https://github.com/libsdl-org/SDL_image).**

dependencies/cimgui

@@ -1 +0,0 @@
-Subproject commit bcb179376b4dbfdc8808716110a9418fe6e73df8

dependencies/cimgui.config

@@ -1,22 +0,0 @@
-#!/usr/bin/env bash
-DEP_WORKING_DIR='dependencies/cimgui'
-DEP_PRE_BUILD_COMMAND=''
-if [[ "$TASK" = *_dbg ]]; then
-    DEP_BUILD_COMMAND='cbuild -c ../cimgui.project.config build_shared_lib_dbg'
-else
-    DEP_BUILD_COMMAND='cbuild -c ../cimgui.project.config build_shared_lib'
-fi
-DEP_POST_BUILD_COMMAND='rm -f cbuild.log'
-DEP_CLEAN_COMMAND='cbuild clean -c ../cimgui.project.config'
-DEP_STATIC_OUT_FILES=''
-case $OS in
-    WINDOWS)
-        DEP_DYNAMIC_OUT_FILES="../bin/cimgui.dll"
-        ;;
-    LINUX)
-        DEP_DYNAMIC_OUT_FILES="../bin/cimgui.so"
-        ;;
-    *)
-        error "operating system $OS has no configuration variants"
-        ;;
-esac

dependencies/imgui

@@ -0,0 +1 @@
+Subproject commit 7b6314f47d2aaa3758cfeeca66af34f5c9309ca4

dependencies/imgui.config

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+DEP_WORKING_DIR='dependencies/imgui'
+DEP_PRE_BUILD_COMMAND=''
+if [[ "$TASK" = *_dbg ]]; then
+    DEP_BUILD_COMMAND='cbuild -c ../imgui.project.config build_static_lib_dbg'
+else
+    DEP_BUILD_COMMAND='cbuild -c ../imgui.project.config build_static_lib'
+fi
+DEP_POST_BUILD_COMMAND=''
+DEP_CLEAN_COMMAND='cbuild clean -c ../imgui.project.config'
+DEP_STATIC_OUT_FILES='../bin/libimgui.a'
+DEP_DYNAMIC_OUT_FILES=''

dependencies/imgui.project.config

@@ -1,8 +1,8 @@
 #!/usr/bin/env bash
-CBUILD_VERSION=2.2.1
+CBUILD_VERSION=2.1.2
 CONFIG_VERSION=1
 
-PROJECT="cimgui"
+PROJECT="imgui"
 CMP_C="gcc"
 CMP_CPP="g++"
 STD_C="c11"
@@ -10,14 +10,13 @@ STD_CPP="c++11"
 WARN_C="-Wall -Wno-discarded-qualifiers -Wno-unused-parameter"
 WARN_CPP="-Wall -Wno-unused-parameter"
 SRC_C=""
-SRC_CPP="imgui/imgui.cpp
+SRC_CPP="imgui.cpp
-    imgui/imgui_demo.cpp
+    imgui_demo.cpp
-    imgui/imgui_draw.cpp
+    imgui_draw.cpp
-    imgui/imgui_tables.cpp
+    imgui_tables.cpp
-    imgui/imgui_widgets.cpp
+    imgui_widgets.cpp
-    imgui/backends/imgui_impl_sdl2.cpp
+    backends/imgui_impl_sdl2.cpp
-    imgui/backends/imgui_impl_sdlrenderer2.cpp
+    backends/imgui_impl_sdlrenderer2.cpp"
-    cimgui.cpp"
 
 # Directory with dependency configs.
 # See cbuild/example_dependency_configs
@@ -32,22 +31,20 @@ ENABLED_DEPENDENCIES=''
 #  └── profile/      - gcc *.gcda profiling info files
 OBJDIR="../obj"
 OUTDIR="../bin"
+STATIC_LIB_FILE="lib$PROJECT.a"
 
 # header include directories
-INCLUDE="-I. -I./imgui -I../include/SDL2"
+INCLUDE="-I. -I../include/SDL2"
 
-STATIC_LIB_FILE="$PROJECT.a"
 # OS-specific options
 case "$OS" in
     WINDOWS)
-        SHARED_LIB_FILE="$PROJECT.dll"
+        EXEC_FILE="$PROJECT.exe"
-        LINKER_LIBS="-L../precompiled/$OS-$ARCH -l:SDL2.dll"
+        SHARED_LIB_FILE="lib$PROJECT.dll"
-        DEFINE="-DIMGUI_API=__declspec(dllexport)"
         ;;
     LINUX)
-        SHARED_LIB_FILE="$PROJECT.so"
+        EXEC_FILE="$PROJECT"
-        LINKER_LIBS="-lSDL2"
+        SHARED_LIB_FILE="lib$PROJECT.so"
-        DEFINE="-DIMGUI_API=__attribute__((__visibility__(\"default\")))"
         ;;
     *)
         error "operating system $OS has no configuration variants"
@@ -58,25 +55,25 @@ esac
 case "$TASK" in
     # creates shared library
     build_shared_lib)
-        C_ARGS="-O2 -fpic -shared $DEFINE"
+        C_ARGS="-O2 -fpic -flto -shared"
         CPP_ARGS="$C_ARGS"
-        LINKER_ARGS="$CPP_ARGS $LINKER_LIBS -Wl,-soname,$SHARED_LIB_FILE"
+        LINKER_ARGS="$CPP_ARGS -Wl,-soname,$SHARED_LIB_FILE"
         PRE_TASK_SCRIPT=
         TASK_SCRIPT=cbuild/default_tasks/build_shared_lib.sh
         POST_TASK_SCRIPT=
         ;;
     # creates shared library with debug symbols and no optimizations
     build_shared_lib_dbg)
-        C_ARGS="-O0 -g3 -fpic -shared $DEFINE"
+        C_ARGS="-O0 -g3 -fpic -shared"
         CPP_ARGS="$C_ARGS"
-        LINKER_ARGS="$CPP_ARGS $LINKER_LIBS -Wl,-soname,$SHARED_LIB_FILE"
+        LINKER_ARGS="$CPP_ARGS -Wl,-soname,$SHARED_LIB_FILE"
         PRE_TASK_SCRIPT=
         TASK_SCRIPT=cbuild/default_tasks/build_shared_lib.sh
         POST_TASK_SCRIPT=
         ;;
     # creates static library
     build_static_lib)
-        C_ARGS="-O2 $DEFINE"
+        C_ARGS="-O2"
         CPP_ARGS="$C_ARGS"
         PRE_TASK_SCRIPT=
         TASK_SCRIPT=cbuild/default_tasks/build_static_lib.sh
@@ -84,7 +81,7 @@ case "$TASK" in
         ;;
     # creates static library with debug symbols and no optimizations
     build_static_lib_dbg)
-        C_ARGS="-O0 -g3 $DEFINE"
+        C_ARGS="-O0 -g3"
         CPP_ARGS="$C_ARGS"
         PRE_TASK_SCRIPT=
         TASK_SCRIPT=cbuild/default_tasks/build_static_lib.sh

dependencies/src-csharp.config

@@ -6,7 +6,4 @@ if [[ "$TASK" = *_dbg ]]; then
 fi
 DEP_BUILD_COMMAND=$"dotnet build src-csharp.sln -o bin -c $CS_CONFIGURATION"
 DEP_CLEAN_COMMAND='rm -rf bin obj'
-DEP_OTHER_OUT_FILES='bin/Ougge.dll
+DEP_OTHER_OUT_FILES='bin/Ougge.dll'
-    bin/Tomlyn.dll
-    bin/Hexa.NET.ImGui.dll
-    bin/HexaGen.Runtime.dll'

project.config

@@ -15,7 +15,7 @@ SRC_CPP="$(find src -name '*.cpp')"
 # See cbuild/example_dependency_configs
 DEPENDENCY_CONFIGS_DIR='dependencies'
 # List of dependency config files in DEPENDENCY_CONFIGS_DIR separated by space.
-ENABLED_DEPENDENCIES='precompiled resources cimgui src-csharp'
+ENABLED_DEPENDENCIES='precompiled resources imgui src-csharp'
 
 # OBJDIR structure:
 #  ├── objects/      - Compiled object files. Cleans on each call of build task
@@ -27,7 +27,7 @@ OUTDIR="bin"
 STATIC_LIB_FILE="lib$PROJECT.a"
 
 # header include directories
-INCLUDE="-I./dependencies/cimgui/imgui -I./dependencies/include -I./dependencies/include/SDL2"
+INCLUDE="-I./dependencies/imgui -I./dependencies/include -I./dependencies/include/SDL2"
 
 # OS-specific options
 case "$OS" in

src-csharp/ExampleComponent.cs

@@ -1,5 +1,4 @@
 using System;
-using Hexa.NET.ImGui;
 
 namespace Ougge;
 
@@ -12,8 +11,5 @@ public class ExampleComponent : Component
     public override void Update(double deltaTime)
     {
         Console.WriteLine($"C# deltaTime {deltaTime} object id {Owner.Id}");
-        ImGui.Begin("C# WINDOW");
-        ImGui.Text("Hello from ExampleComponent!");
-        ImGui.End();
     }
 }

src-csharp/GameObject.cs

@@ -65,8 +65,7 @@ public class GameObject
         if(Components.ContainsKey(t))
             return false;
         
-        Component component = (Component?)Activator.CreateInstance(t, this) 
+        Component component = (Component)Activator.CreateInstance(t, this);
-            ?? throw new Exception($"can't create instance of class {t.FullName}");
         Components.Add(t, component);
         return true;
     }

src-csharp/Ougge.csproj

@@ -6,10 +6,5 @@
     <ImplicitUsings>disable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <DebugType>embedded</DebugType>
-    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
   </PropertyGroup>
-  <ItemGroup>
-    <PackageReference Include="Hexa.NET.ImGui" Version="2.2.7" />
-    <PackageReference Include="Tomlyn" Version="0.19.0" />
-  </ItemGroup>
 </Project>

src/Engine.cpp

@@ -1,22 +1,26 @@
 #include "Engine.hpp"
-#include "common/UsefulException.hpp"
+#include "gui/gui.hpp"
-#include "common/ougge_format.hpp"
-#include "common/time.hpp"
-#include <SDL2/SDL.h>
-#include <iostream>
 
 namespace ougge {
 
-IEngineModule::IEngineModule(Engine& engine)
+Engine::Engine()
-    : engine(engine)
+    : gameObjectPool(GAMEOBJECTPOOL_SIZE) 
-{}
-
-void IEngineModule::beginFrame() {}
-void IEngineModule::endFrame() {}
-
-
-void Engine::startLoop()
 {
+}
+
+void Engine::init(){
+    engineManagedAssembly = mono.loadAssembly("Ougge.dll");
+    gameObjectClass = engineManagedAssembly->getClass("Ougge", "GameObject");
+    gameObjectCtor = Mono::Method<void(u64, u32)>(gameObjectClass, ".ctor");
+    gameObjectInvokeUpdate = Mono::Method<void(f64)>(gameObjectClass, "InvokeUpdate");
+    gameObjectTryCreateComponent = Mono::Method<Mono::Bool(Mono::String)>(gameObjectClass, "TryCreateComponent_internal");
+}
+
+void Engine::openMainWindow(const std::string& window_title){
+    mainWindow.open(window_title);
+}
+
+void Engine::startLoop(){
     if(loop_running)
         throw UsefulException("loop is running already");
     
@@ -24,79 +28,87 @@ void Engine::startLoop()
     loop_running=true;
     // main loop
     while(loop_running){
+        mainWindow.pollEvents(&loop_running);
+        if(!loop_running)
+            break;
+        
         nsec_t update_time_ns = getMonotonicTimeNsec();
         if(update_time_ns < prev_update_time_ns)
             throw UsefulException("monotonic clock returned unexpected value");
         f64 delta_time_s = (f64)(update_time_ns - prev_update_time_ns) / 1e9;
         prev_update_time_ns = update_time_ns;
-        deltaTime = delta_time_s;
         
-        tryDrawFrame();
+        tryDrawFrame(delta_time_s);
         
         nsec_t after_update_time_ns = getMonotonicTimeNsec();
-        nsec_t frame_delay_ns = (nsec_t)1e9 / fps_max - (after_update_time_ns - update_time_ns);
+        nsec_t frame_delay_ns = (nsec_t)1e9 / mainWindow.fps_max - (after_update_time_ns - update_time_ns);
         if(frame_delay_ns > 0){
             SDL_Delay(frame_delay_ns / 1e6);
         }
     }
+
+    mainWindow.close();
 }
 
 void Engine::stopLoop(){
     loop_running = false;
 }
 
-void Engine::handleModuleError(IEngineModule& module, const char* type, const char* method, const char* error){
+void Engine::tryDrawFrame(f64 deltaTime){
-    std::string error_message = ougge_format(
+    static std::string error_message;
-        "Catched %s at %s.%s(): %s",
+    static bool draw_error_window = false;
-        type, module.getName(), method, error);
+    try {
-    std::cerr<<error_message<<std::endl;
+        mainWindow.beginFrame();
-    error_messages.push_back(error_message);
-}
         
-void Engine::tryDrawFrame(){
+        if(draw_error_window)
-    auto it = modules.begin();
+            gui::drawErrorWindow(error_message, &draw_error_window);
-    while(it != modules.end())
+        else {
-    {
+            updateGameObjects(deltaTime);
-        IEngineModule& module = **it;
+            if(!updateCallback.isNull())
-        it++;
+                updateCallback(deltaTime);
-        try {
-            module.beginFrame();
-        }
-        catch(const std::exception& e){
-            handleModuleError(module, "exception", "beginFrame", e.what());
-        }
-        catch(const char* cstr){
-            handleModuleError(module, "error message (const char*)", "beginFrame", cstr);
-        }
-        catch(const std::string& str){
-            handleModuleError(module, "error message (std::string)", "beginFrame", str.c_str());
-        }
-        catch(...){
-            handleModuleError(module, "unknown", "beginFrame", "unknown");
         }
+        mainWindow.endFrame();
     }
-
+    catch(const std::exception& e){
-    it = modules.end();
+        error_message = "Catched exception: " + std::string(e.what());
-    while(it != modules.begin())
+        draw_error_window = true;
-    {
+        std::cerr<<error_message<<std::endl;
-        it--;
+    }
-        IEngineModule& module = **it;
+    catch(const char* cstr){
-        try {
+        error_message = "Catched error message (const char*): " + std::string(cstr);
-            module.endFrame();
+        draw_error_window = true;
-        }
+        std::cerr<<error_message<<std::endl;
-        catch(const std::exception& e){
+    }
-            handleModuleError(module, "exception", "endFrame", e.what());
+    catch(const std::string& str){
-        }
+        error_message = "Catched error message (std::string): " + str;
-        catch(const char* cstr){
+        draw_error_window = true;
-            handleModuleError(module, "error message (const char*)", "endFrame", cstr);
+        std::cerr<<error_message<<std::endl;
-        }
+    }
-        catch(const std::string& str){
+    catch(...){
-            handleModuleError(module, "error message (std::string)", "endFrame", str.c_str());
+        error_message = "Catched unknown error";
-        }
+        draw_error_window = true;
-        catch(...){
+        std::cerr<<error_message<<std::endl;
-            handleModuleError(module, "unknown", "endFrame", "unknown");
-        }
     }
 }
 
+
+void Engine::updateGameObjects(f64 deltaTime){
+    for(auto pair : gameObjectPool){
+        gameObjectInvokeUpdate(pair.second.getObjectHandle().getObject(), deltaTime);
+    }
+}
+
+game::GameObject& Engine::createGameObject(){
+    auto pair = gameObjectPool.emplace(game::GameObject(mono.createObject(gameObjectClass)));
+    game::GameObject& obj = pair.second;
+    gameObjectCtor(obj.getObjectHandle().getObject(), ++obj_id, pair.first);
+    return obj;
+}
+
+bool Engine::tryCreateComponent(game::GameObject& obj, const std::string& componentClassName){
+    Mono::String componentClassNameManaged = mono.createString(componentClassName);
+    Mono::Bool created = gameObjectTryCreateComponent(obj.getObjectHandle().getObject(), componentClassNameManaged);
+    return created.wide_bool;
+}
+
 }

src/Engine.hpp

@@ -1,106 +1,50 @@
 #pragma once
 
-#include <vector>
+#include "common/function_shared_ptr.hpp"
-#include "common/std.hpp"
+#include "mono/mono.hpp"
-#include "common/UsefulException.hpp"
+#include "game/GameObjectPool.hpp"
-#include "common/ougge_format.hpp"
+#include "gui/MainWindow.hpp"
-#include "common/type_name_demangled.hpp"
+#include "resources/textures.hpp"
-#include <type_traits>
-#include <memory>
-#include <iostream>
 
 namespace ougge {
 
-class Engine;
+#define GAMEOBJECTPOOL_SIZE 64*1024
-
-class IEngineModule {
-public:
-    IEngineModule() = delete;
-    IEngineModule(const IEngineModule&) = delete;
-    IEngineModule& operator=(const IEngineModule&) = delete;
-    IEngineModule(IEngineModule&&) = delete;
-    IEngineModule& operator=(IEngineModule&&) = delete;
-
-    Engine& engine;
-    virtual const std::string& getName() = 0;
-
-    virtual void beginFrame();
-    virtual void endFrame();
-
-protected:
-    IEngineModule(Engine& engine);
-};
 
+using UpdateFunc_t = function_shared_ptr<void(f64)>;
 
 class Engine {
-    std::vector<std::unique_ptr<IEngineModule>> modules;
     bool loop_running = false;
 
+    game::GameObjectPool gameObjectPool;
+    u64 obj_id = 0;
+    MonoClass* gameObjectClass;
+    Mono::Method<void(u64, u32)> gameObjectCtor;
+    Mono::Method<void(f64)> gameObjectInvokeUpdate;
+    Mono::Method<Mono::Bool(Mono::String)> gameObjectTryCreateComponent;
+    
 public:
-    u32 fps_max = 60;
+    gui::MainWindow mainWindow;
-    f64 deltaTime;
+    UpdateFunc_t updateCallback;
-    std::vector<std::string> error_messages;
 
-    Engine() = default;
+    Mono::RuntimeJIT mono;
-    Engine(const Engine&) = delete;
+    std::shared_ptr<Mono::Assembly> engineManagedAssembly;
-    Engine& operator=(const Engine&) = delete;
-    Engine(Engine&&) = delete;
-    Engine& operator=(Engine&&) = delete;
 
+    resources::CacheStorage<resources::Texture> textures;
+
+    Engine();
+    void init();
+    void openMainWindow(const std::string& window_title);
     // start game loop on the current thread
     void startLoop();
     void stopLoop();
 
-    //TODO: add std::enable_if
+    game::GameObject& createGameObject();
-    template<typename ModuleT, typename... ConstructorArgsT>
+    bool tryCreateComponent(game::GameObject& obj, const std::string& componentClassName);
-    ModuleT& createModule(ConstructorArgsT&&... args){
-        static_assert(std::is_base_of<IEngineModule, ModuleT>::value);
     
-        auto& module_type_name = ougge_type_name<ModuleT>();
-        //TODO: replace with some logger call
-        std::cout<<"Initializing module '"<<module_type_name<<"'"<<std::endl;
-        
-        size_t module_index;
-        bool module_exists;
-        getOrCreateModuleIndex<ModuleT>(&module_index, &module_exists);
-
-        if(module_exists){
-            throw UsefulException(ougge_format("can't create second instance of module '%s'", 
-                module_type_name.c_str()));
-        }
-
-        //TODO: std::forward(args)...
-        modules.push_back(std::make_unique<ModuleT>(*this, args...));
-        return *static_cast<ModuleT*>(modules[module_index].get());
-    }
-
-    //TODO: add std::enable_if
-    template<typename ModuleT>
-    ModuleT& getModule(){
-        static_assert(std::is_base_of<IEngineModule, ModuleT>::value);
-        
-        size_t module_index;
-        bool module_exists;
-        getOrCreateModuleIndex<ModuleT>(&module_index, &module_exists);
-        if(!module_exists){
-            auto& module_type_name = ougge_type_name<ModuleT>();
-            throw UsefulException(ougge_format("engine has no module '%s'", 
-                module_type_name.c_str()));
-        }
-        return *static_cast<ModuleT*>(modules[module_index].get());
-    } 
 
 private:
-    void tryDrawFrame();
+    void tryDrawFrame(f64 deltaTime);
-    void handleModuleError(IEngineModule& module, const char *type, const char *method, const char *error);
+    void updateGameObjects(f64 deltaTime);
-
-    //TODO: add std::enable_if
-    template<typename ModuleT>
-    void getOrCreateModuleIndex(size_t* out_index, bool* out_module_exists){
-        static size_t module_index = modules.size();
-        *out_index = module_index;
-        // if module_index == modules.size(), then the module hasn't been pushed to the vector yet
-        *out_module_exists = module_index != modules.size();
-    }
 };
+
 }

src/GUI/MainWindow.cpp

@@ -1,20 +1,16 @@
 #include <backends/imgui_impl_sdl2.h>
 #include <backends/imgui_impl_sdlrenderer2.h>
 #include <iostream>
-#include "MainWindowSDL2.hpp"
+#include "MainWindow.hpp"
-#include "../gui/gui_exceptions.hpp"
+#include "gui_exceptions.hpp"
 #include "../common/ougge_format.hpp"
+#include "../resources/fonts.hpp"
+#include "../resources/textures.hpp"
 #include "../common/math.hpp"
 
-using namespace ougge::gui;
+namespace ougge::gui {
 
-namespace ougge::modules {
+f32 MainWindow::getDPI(){
-
-const std::string& MainWindowSDL2::getName() {
-    return ougge_type_name<MainWindowSDL2>();
-}
-
-f32 MainWindowSDL2::getDPI(){
     i32 w=0, h=0;
     SDL_GetRendererOutputSize(sdl_renderer, &w, &h);
     i32 sim_w=0, sim_h=0;
@@ -25,11 +21,7 @@ f32 MainWindowSDL2::getDPI(){
     return dpi;
 }
 
-MainWindowSDL2::MainWindowSDL2(Engine& engine,
+void MainWindow::open(const std::string& window_title){
-        const std::string& window_title,
-        resources::ResourceManager& resourceManager)
-    : IEngineModule(engine)
-{
     SDL_TRY(SDL_Init(SDL_INIT_EVERYTHING));
     SDL_version v;
     SDL_GetVersion(&v);
@@ -80,15 +72,11 @@ MainWindowSDL2::MainWindowSDL2(Engine& engine,
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
-    
-    resources::ResourceFactory* font_res = resourceManager.tryGetResource(default_font_path);
-    if(font_res == nullptr)
-        throw UsefulException("can't find default font resource");
     f32 dpi = getDPI();
-    io.FontDefault = resources::ImFont_LoadFromResource(font_res, default_font_size, dpi);
+    io.FontDefault = resources::ImFont_LoadFromResource(default_font, default_font_size, dpi);
 }
 
-MainWindowSDL2::~MainWindowSDL2(){
+void MainWindow::close(){
     ImGui_ImplSDLRenderer2_Shutdown();
     ImGui_ImplSDL2_Shutdown();
     ImGui::DestroyContext();
@@ -97,22 +85,20 @@ MainWindowSDL2::~MainWindowSDL2(){
     SDL_Quit();
 }
 
-void MainWindowSDL2::pollEvents(){
+void MainWindow::pollEvents(bool* loopRunning){
     SDL_Event event;
     while (SDL_PollEvent(&event)) {
         ImGui_ImplSDL2_ProcessEvent(&event);
         switch(event.type){
             case SDL_QUIT: {
-                //TODO: log SDL_QUIT event
+                *loopRunning = false;
-                engine.stopLoop();
                 break;
             }
             case SDL_WINDOWEVENT: {
                 if(event.window.event == SDL_WINDOWEVENT_CLOSE 
                     && event.window.windowID == SDL_GetWindowID(sdl_window))
                 {
-                    //TODO: log SDL_WINDOWEVENT event
+                    *loopRunning = false;
-                    engine.stopLoop();
                 }
                 break;
             }
@@ -120,10 +106,8 @@ void MainWindowSDL2::pollEvents(){
     }
 }
 
-void MainWindowSDL2::beginFrame(){
-    // process events happend since previous frame
-    pollEvents();
 
+void MainWindow::beginFrame(){
     // Start the Dear ImGui frame
     ImGui_ImplSDLRenderer2_NewFrame();
     ImGui_ImplSDL2_NewFrame();
@@ -140,17 +124,16 @@ void MainWindowSDL2::beginFrame(){
 
     draw_bg_window();
     draw_debug_window();
-    drawErrorWindow();
 }
 
-void MainWindowSDL2::endFrame(){
+void MainWindow::endFrame(){
     ImGui::Render();
     ImGui_ImplSDLRenderer2_RenderDrawData(ImGui::GetDrawData(), sdl_renderer);
     // Swap buffers
     SDL_RenderPresent(sdl_renderer);
 }
 
-void MainWindowSDL2::draw_bg_window(){
+void MainWindow::draw_bg_window(){
     const ImGuiDockNodeFlags dockspace_flags =
             ImGuiDockNodeFlags_PassthruCentralNode;
     const ImGuiWindowFlags window_flags =
@@ -214,11 +197,11 @@ void MainWindowSDL2::draw_bg_window(){
     ImGui::End();
 }
 
-void MainWindowSDL2::draw_debug_window(){
+void MainWindow::draw_debug_window(){
     ImGuiIO& io = ImGui::GetIO();
     if(ImGui::Begin("Debug Options", &show_debug_window)){
         ImGui::ColorEdit3("clear_color", (float*)&clear_color);
-        ImGui::InputInt("fps_max", (int*)&engine.fps_max);
+        ImGui::InputInt("fps_max", &fps_max);
         ImGui::Text("Application average %.3f ms/frame (%.2f FPS)", 1000.0f / io.Framerate, io.Framerate);
         ImGui::Checkbox("Demo Window", &show_demo_window);
         ImGui::Checkbox("Metrics/Debug Window", &show_metrics_window);
@@ -232,16 +215,4 @@ void MainWindowSDL2::draw_debug_window(){
         ImGui::ShowMetricsWindow(&show_metrics_window);
 }
 
-void MainWindowSDL2::drawErrorWindow(){
-    if(engine.error_messages.size() < 1)
-        return;
-    ImGui::Begin("ERRORS");
-        if(ImGui::Button("Clear"))
-            engine.error_messages.clear();
-        for(auto& msg : engine.error_messages){
-            ImGui::TextWrapped("%s", msg.c_str());
-        }
-    ImGui::End();
-}
-
 }

src/GUI/MainWindow.hpp

@@ -2,23 +2,21 @@
 
 #include <SDL.h>
 #include <imgui.h>
-#include <vector>
 #include "../common/std.hpp"
-#include "../resources/resources.hpp"
+#include "../common/time.hpp"
-#include "../resources/fonts.hpp"
-#include "../Engine.hpp"
-
-namespace ougge::modules {
 
 /// converts hex color to float vector
 #define RGBAHexToF(R8,G8,B8,A8) ImVec4(((u8)35)/255.0f, ((u8)35)/255.0f, ((u8)50)/255.0f, ((u8)255)/255.0f)
 /// converts float vector to hex color
 #define RGBAFToHex(VEC4) {(u8)(VEC4.x*255), (u8)(VEC4.y*255), (u8)(VEC4.z*255), (u8)(VEC4.w*255)}
 
-#define default_font_path "fonts/DroidSans.ttf"
+namespace ougge::gui {
 
-class MainWindowSDL2 : public IEngineModule {
+#define default_font "DroidSans"
+
+class MainWindow {
 public:
+    i32 fps_max = 60;
     f32 default_font_size = 14.0f;
     ImVec4 clear_color = RGBAHexToF(35,35,50,255);
     SDL_Window* sdl_window = nullptr;
@@ -30,20 +28,18 @@ private:
     bool show_metrics_window = false;
 
 public:
-    MainWindowSDL2(Engine& engine, const std::string& window_title,
+    void open(const std::string& window_title);
-        resources::ResourceManager& resourceManager);
+    void close();
-    ~MainWindowSDL2();
 
-    const std::string& getName() override;
+    /// process io events happened since previous frame
-    void beginFrame() override;
+    void pollEvents(bool* loopRunning);
-    void endFrame() override;
+    void beginFrame();
+    void endFrame();
 
     f32 getDPI();
 private:
-    void pollEvents();
     void draw_debug_window();
     void draw_bg_window();
-    void drawErrorWindow();
 };
 
 }

src/Game/GameObject.cpp

@@ -0,0 +1,30 @@
+#include "GameObject.hpp"
+
+namespace ougge::game {
+
+std::ostream& operator<<(std::ostream& s, Transform& t){
+    s<<"{ position: {x: "<<t.position.x<<", y: "<<t.position.y;
+    s<<"}, rotation: "<<t.rotation;
+    s<<", scale {x: "<<t.scale.x<<", y: "<<t.scale.y<<"} }";
+    return s;
+}
+
+GameObject::GameObject(Mono::Object managed_obj)
+    : object_handle(managed_obj) 
+{}
+
+GameObject::GameObject(GameObject &&o) :
+    object_handle(std::move(o.object_handle)),
+    parent(o.parent),
+    transform(o.transform)
+{
+}
+
+GameObject& GameObject::operator=(GameObject &&o){
+    object_handle = std::move(o.object_handle);
+    parent = o.parent;
+    transform = o.transform;
+    return *this;
+}
+
+}

src/Game/GameObject.hpp

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <map>
+#include <iostream>
+#include "../common/math.hpp"
+#include "../common/UsefulException.hpp"
+#include "../mono/mono.hpp"
+
+namespace ougge::game {
+
+class GameObject;
+
+struct Transform {
+    Vec2 scale = { 1, 1 };
+    Vec2 position = { 0, 0 };
+    angle_t rotation = 0;
+};
+
+std::ostream& operator<<(std::ostream& s, Transform& t);
+
+
+class GameObject {
+    Mono::ObjectHandle object_handle;
+    GameObject* parent;
+    Transform transform;
+
+public:
+    /// @warning Do not use this to create objects.
+    /// This constructor creates null values for GameObject arrays
+    /// GameObject* array = new GameObject[10];
+    /// array[0] = GameObject(initialized_mono_object_ptr)
+    GameObject() = default;
+    GameObject(Mono::Object managed_obj);
+    GameObject(const GameObject& o) = delete;
+    GameObject(GameObject&& o);
+    
+    GameObject& operator=(GameObject&& o);
+
+    inline Mono::ObjectHandle& getObjectHandle() { return object_handle; }
+    inline GameObject* getParent() { return parent; }
+    inline void setParent(GameObject* p) { parent = p; }
+    inline Transform& getTransform() { return transform; }
+};
+
+}

src/Game/GameObjectPool.cpp

@@ -0,0 +1,130 @@
+#include "GameObjectPool.hpp"
+#include <bit>
+#include <cstring>
+
+namespace ougge::game {
+
+GameObjectPool::GameObjectPool(u32 size)
+{
+    useful_assert(size % 64 == 0, "size of GameObjectPool must be a multiple of 64");
+    this->size = size; 
+    first_unused_index = 0;
+    buffer = new GameObject[size];
+    used_indices = new u64[size/64];
+    // std::memset(buffer, 0, size*sizeof(GameObject));
+    std::memset(used_indices, 0, size/8);
+}
+
+GameObjectPool::~GameObjectPool()
+{
+    delete[] buffer;
+    delete[] used_indices;
+}
+
+bool GameObjectPool::isIndexUsed(u32 index)
+{
+    return ( used_indices[index/64] & (u64(1)<<(index%64)) ) != 0;
+}
+
+u32 GameObjectPool::getNearestUnusedIndex(u32 startIndex)
+{
+    if(startIndex >= size)
+        return -1;
+    if(!isIndexUsed(startIndex))
+        return startIndex;
+    
+    u32 i = startIndex/64;
+    // mark previous bits as used
+    u64 u = used_indices[i] | ( (u64(1)<<startIndex%64) -1 );
+    while(u == u64(-1)){
+        i++;
+        if(i == size/64)
+            return -1;
+        u = used_indices[i];
+    }
+    u32 bitpos = std::countr_one(u);
+    if(bitpos == 64)
+        return -1;
+    u32 index = i*64 + bitpos;
+    return index;
+}
+
+u32 GameObjectPool::getNearestUsedIndex(u32 startIndex)
+{
+    if(startIndex >= size)
+        return -1;
+    if(isIndexUsed(startIndex))
+        return startIndex;
+    
+    u32 i = startIndex/64;
+    // mark previous bits as unused
+    u64 u = used_indices[i] & !( (u64(1)<<startIndex%64) -1 );
+    while(u == 0){
+        i++;
+        if(i == size/64)
+            return -1;
+        u = used_indices[i];
+    }
+    u32 bitpos = std::countr_zero(u);
+    if(bitpos == 64)
+        return -1;
+    u32 index = i*64 + bitpos;
+    return index;
+}
+
+GameObject& GameObjectPool::get(u32 index)
+{
+    if(index >= size)
+        throw UsefulException(ougge_format("index %i is out of size %i", index, size));
+    if(!isIndexUsed(index))
+        throw UsefulException(ougge_format("there is no object at index %i", index));
+    return buffer[index];
+}
+
+std::pair<u32, GameObject&> GameObjectPool::emplace(GameObject&& new_obj)
+{
+    u32 i = first_unused_index;
+    if(i == u32(-1))
+        throw UsefulException("can't put new GameObject to GameObjectPool because it's full");
+    
+    buffer[i] = std::move(new_obj);
+    GameObject& r = buffer[i];
+    used_indices[i/64] |= u64(1)<<(i%64); // mark index bit as used
+    first_unused_index = getNearestUnusedIndex(i+1);
+    return std::pair<u32, GameObject&>(i, r);
+}
+
+void GameObjectPool::erase(u32 index)
+{
+    if(index >= size)
+        throw UsefulException(ougge_format("index %i is out of size %i", index, size));
+    if(!isIndexUsed(index))
+        throw UsefulException(ougge_format("there is no object at index %i", index));
+    
+    buffer[index] = GameObject();
+    used_indices[index/64] &= ~(u64(1)<<(index%64)); // mark index bit as unused
+    if(index < first_unused_index)
+        first_unused_index = index;
+}
+
+GameObjectPool::iterator::iterator(GameObjectPool* pool, u32 index)
+    : pool(pool), index(index)
+{
+}
+
+std::pair<u32, GameObject&> GameObjectPool::iterator::operator*()
+{
+    if(index >= pool->size)
+        throw UsefulException("can't get value of end() iterator");
+    
+    GameObject& r = pool->buffer[index];
+    return  std::pair<u32, GameObject&>(index, r);
+}
+
+GameObjectPool::iterator& GameObjectPool::iterator::operator++()
+{
+    index = pool->getNearestUsedIndex(index+1);
+    return *this;
+}
+
+}

src/Game/GameObjectPool.hpp

@@ -0,0 +1,70 @@
+#include "GameObject.hpp"
+
+namespace ougge::game {
+
+/*
+Fixed array that stores deleted elements indices as bits in array of u64.
+Fast emplace, erase and lookup. 
+
+------------------------[construct]------------------------
+operation 'GameObjectPool::GameObjectPool()' took 1.0549 ms
+operation 'other_collections_construct' took 0.0133 ms
+-------------------------[emplace]-------------------------
+operation 'GameObjectPool::emplace' took 8.0557 ms
+operation 'vector::emplace_back' took 11.3735 ms
+operation 'set::emplace' took 80.5633 ms
+operation 'list::emplace_front' took 18.1442 ms
+operation 'forward_list::emplace_front' took 11.5467 ms
+--------------------------[erase]--------------------------
+operation 'GameObjectPool::erase' took 0.2745 ms
+operation 'vector::erase' took 15790.6 ms
+operation 'set::erase' took 1.2697 ms
+operation 'list::erase_after' took 0.93 ms
+operation 'forward_list::erase_after' took 1.1127 ms
+-------------------------[iterate]-------------------------
+operation 'GameObjectPool::iterate' took 1.1166 ms
+operation 'vector::iterate' took 0.8883 ms
+operation 'set::iterate' took 2.8011 ms
+operation 'list::iterate' took 2.0766 ms
+operation 'forward_list::iterate' took 2.0823 ms
+*/
+
+class GameObjectPool {
+    GameObject* buffer;
+    u64* used_indices;
+    u32 size;
+    u32 first_unused_index;
+
+    bool isIndexUsed(u32 index);
+    u32 getNearestUnusedIndex(u32 startIndex);
+    u32 getNearestUsedIndex(u32 startIndex);
+public:
+
+    ///@param size must be a multiple of 64
+    GameObjectPool(u32 size);
+    ~GameObjectPool();
+    GameObject& get(u32 index);
+    std::pair<u32, GameObject&> emplace(GameObject&& new_obj);
+    void erase(u32 index);
+
+    #pragma region iterator class
+    class iterator {
+        GameObjectPool* pool;
+        u32 index = 0;
+    
+    public:
+        iterator(GameObjectPool* pool, u32 index);
+        std::pair<u32, GameObject&> operator*();
+        iterator& operator++();
+        inline bool operator!=(const iterator& o) const { return index != o.index; };
+        inline bool operator==(const iterator& o) const { return index == o.index; };
+    };
+    #pragma endregion
+
+    inline iterator begin() { return iterator(this, 0); }
+    inline iterator end() { return iterator(this, -1); }
+    
+    friend class iterator;
+};
+
+}

src/Mono/Assembly.cpp

@@ -0,0 +1,17 @@
+#include "mono.hpp"
+
+namespace Mono {
+
+Assembly::Assembly(MonoAssembly *ptr)
+    : ptr(ptr), image(mono_assembly_get_image(ptr))
+{
+}
+
+MonoClass* Assembly::getClass(const std::string &name_space, const std::string &name){
+    auto c = mono_class_from_name(image, name_space.c_str(), name.c_str());
+    if(!c)
+        throw UsefulException(ougge_format("can't get class '%s.%s'", name_space.c_str(), name.c_str()));
+    return c;
+}
+
+}

src/Mono/Mono.cpp

@@ -0,0 +1,81 @@
+#include "mono.hpp"
+#include <mono/metadata/appdomain.h>
+
+namespace Mono {
+
+template <> MonoClass* getClass<SByte>(){ return mono_get_sbyte_class(); }
+template <> MonoClass* getClass<Byte>(){ return mono_get_byte_class(); }
+template <> MonoClass* getClass<Short>(){ return mono_get_int16_class(); }
+template <> MonoClass* getClass<UShort>(){ return mono_get_uint16_class(); }
+template <> MonoClass* getClass<Int>(){ return mono_get_int32_class(); }
+template <> MonoClass* getClass<UInt>(){ return mono_get_uint32_class(); }
+template <> MonoClass* getClass<Long>(){ return mono_get_int64_class(); }
+template <> MonoClass* getClass<ULong>(){ return mono_get_uint64_class(); }
+template <> MonoClass* getClass<Float>(){ return mono_get_single_class(); }
+template <> MonoClass* getClass<Double>(){ return mono_get_double_class(); }
+template <> MonoClass* getClass<Bool>(){ return mono_get_boolean_class(); }
+template <> MonoClass* getClass<Char>(){ return mono_get_char_class(); }
+template <> MonoClass* getClass<String>(){ return mono_get_string_class(); }
+template <> MonoClass* getClass<Object>(){ return mono_get_object_class(); }
+template <> MonoClass* getClass<Void>(){ return mono_get_void_class(); }
+
+
+void getMethodSignatureTypes(MonoMethod* mono_method,
+        MonoType** return_type,
+        std::vector<MonoType*>& argument_types)
+{
+    auto signature = mono_method_signature(mono_method);
+    void* iter = nullptr;
+    *return_type = mono_signature_get_return_type(signature);
+    MonoType* pt = nullptr;
+    while( (pt = mono_signature_get_params(signature, &iter)) ){
+        argument_types.push_back(pt);
+    }
+}
+
+MonoMethod* tryGetMonoMethod(MonoClass* target_class, const std::string& name,
+        MonoClass* return_class, MonoClass* arg_classes[], size_t arg_classes_size)
+{
+    if(target_class == nullptr)
+        throw UsefulException("target_class is nullptr");
+    
+    // iterate each method
+    void* iter = nullptr;
+    MonoMethod* m = nullptr;
+    std::vector<MonoType*> argument_types;
+    while( (m = mono_class_get_methods(target_class, &iter)) ){
+        // compare name
+        std::string m_name = mono_method_get_name(m);
+        if(m_name != name)
+            continue;
+        
+        argument_types.clear();
+        MonoType* return_type = nullptr;
+        getMethodSignatureTypes(m, &return_type, argument_types);
+        // compare argument count
+        if(argument_types.size() != arg_classes_size)
+            continue;
+        
+        // compare return type
+        if(!mono_metadata_type_equal(return_type, mono_class_get_type(return_class)))
+            continue;
+        
+        // compare argument types
+        bool argument_types_mismatch = false;
+        for(size_t i = 0; i < arg_classes_size; i++){
+            if(!mono_metadata_type_equal(argument_types[i], mono_class_get_type(arg_classes[i]))){
+                argument_types_mismatch = true;
+                break;
+            }
+        }
+        if(argument_types_mismatch)
+            continue;
+        
+        // passed all tests successfully
+        break;
+    }
+
+    return m;
+}
+
+}

src/Mono/Mono.hpp

@@ -0,0 +1,187 @@
+#pragma once
+
+#include "../common/std.hpp"
+#include "../common/UsefulException.hpp"
+#include "../common/ougge_format.hpp"
+#include <vector>
+#include <type_traits>
+#include <mono/metadata/class.h>
+#include <mono/metadata/assembly.h>
+#include <mono/metadata/object.h>
+
+namespace Mono {
+
+typedef i8 SByte;
+typedef u8 Byte;
+typedef i16 Short;
+typedef u16 UShort;
+typedef i32 Int;
+typedef u32 UInt;
+typedef i64 Long;
+typedef u64 ULong;
+typedef f32 Float;
+typedef f64 Double;
+typedef union { mono_bool wide_bool; } Bool; //USAGE: Bool t = {true};
+typedef char16_t Char;
+typedef MonoString* String;
+/// @warning MonoObject can be moved in memory by GC in any time and raw pointer will be invalid. 
+/// Use ObjectHandle where it is possible.
+typedef MonoObject* Object;
+typedef void Void;
+
+
+template<typename PrimitiveT>
+MonoClass* getClass(); 
+
+template<typename T>
+void* valueToVoidPtr(T& v){ return &v; }
+template<>
+inline void* valueToVoidPtr<Object>(Object& v){ return v; }
+template<>
+inline void* valueToVoidPtr<String>(String& v){ return v; }
+
+template<typename T>
+T valueFromMonoObject(MonoObject* o){
+    void* result_value_ptr = mono_object_unbox(o);
+    if(result_value_ptr == nullptr)
+        throw UsefulException("can't unbox method value");
+    return *((T*)result_value_ptr);
+}
+template<>
+inline Object valueFromMonoObject<Object>(MonoObject* o){ return o; }
+template<>
+inline String valueFromMonoObject<String>(MonoObject* o){ return (String)((void*)o); }
+
+void getMethodSignatureTypes(MonoMethod* mono_method,
+        MonoType** return_type,
+        std::vector<MonoType*>& argument_types);
+
+/// searches for method `name` in `target_class` with return type `return_class` and argument types `arg_classes`
+/// @return found method or nullptr
+MonoMethod* tryGetMonoMethod(MonoClass* target_class, const std::string& name,
+    MonoClass* return_class, MonoClass* arg_classes[], size_t arg_classes_size);
+
+
+template<typename SignatureT> class Method;
+template<typename ReturnT, typename... ArgTypes>
+class Method<ReturnT(ArgTypes...)>
+{
+    MonoMethod* method_ptr;
+
+public:
+    Method() { method_ptr = nullptr; }
+
+    /// all types must implement getClass<T>()
+    Method(MonoClass* target_class, const std::string& name){
+        static MonoClass* arg_classes[] { getClass<ArgTypes>()... };
+        static MonoClass* return_class { getClass<ReturnT>() };
+        method_ptr = tryGetMonoMethod(target_class, name, return_class, arg_classes, sizeof...(ArgTypes));
+        if(method_ptr == nullptr){
+            throw UsefulException(ougge_format("can't get method '%s' from class '%s'",
+                name.c_str(), mono_class_get_name(target_class)));
+        }
+    }
+
+    // ReturnT not is void
+    template<typename RT = ReturnT>
+    std::enable_if_t<!std::is_void<RT>::value, RT> operator()(MonoObject* class_instance, ArgTypes... args) const {
+        if(method_ptr == nullptr)
+            throw UsefulException("method_ptr is null");
+        
+        void* arg_array[] = { valueToVoidPtr(args)..., nullptr };
+        MonoObject* ex = nullptr;
+        MonoObject* result = mono_runtime_invoke(method_ptr, class_instance, arg_array, &ex);
+        if(ex){
+            //TODO:  call mono_trace_set_printerr_handler from  mono/mono/utils/mono-logger.h
+            mono_print_unhandled_exception(ex);
+            throw UsefulException("Some C# exception occured");
+        }
+        return valueFromMonoObject<ReturnT>(result);
+    };
+
+    // ReturnT is void
+    template<typename RT = ReturnT>
+    std::enable_if_t<std::is_void<RT>::value, RT> operator()(MonoObject* class_instance, ArgTypes... args) const {
+        if(method_ptr == nullptr)
+            throw UsefulException("method_ptr is null");
+        
+        void* arg_array[] = { valueToVoidPtr(args)..., nullptr };
+        MonoObject* ex = nullptr;
+        mono_runtime_invoke(method_ptr, class_instance, arg_array, &ex);
+        if(ex){
+            //TODO:  call mono_trace_set_printerr_handler from  mono/mono/utils/mono-logger.h
+            mono_print_unhandled_exception(ex);
+            throw UsefulException("Some C# exception occured");
+        }
+    };
+};
+
+
+class Assembly {
+    MonoAssembly* ptr;
+    MonoImage* image;
+
+public:
+    Assembly(MonoAssembly* ptr);
+    Assembly(const Assembly&) = delete;
+    
+    MonoClass* getClass(const std::string& name_space, const std::string& name);
+    MonoAssembly* getMonoAssembly() const { return ptr; }
+    MonoImage* getMonoImage() const { return image; }
+};
+
+
+///LINUX: `config.xml`, `mscorelib.dll`, `libmono-native.so` in `mono-libs` directory
+///
+///WINDOWS: `config.xml`, `mscorelib.dll` in `mono-libs` directory
+class RuntimeJIT {
+    MonoDomain* domain;
+public:
+    RuntimeJIT(const std::string& domain_name = "OuggeDomain");
+    RuntimeJIT(const RuntimeJIT&) = delete;
+    ~RuntimeJIT();
+    
+    inline MonoDomain* getDomain() { return domain; }
+    std::shared_ptr<Assembly> loadAssembly(const std::string& name);
+
+    inline Object createObject(MonoClass* klass) { return mono_object_new(domain, klass); }
+    inline String createString(const std::string& v) { return mono_string_new_len(domain, v.c_str(), v.size()); }
+    inline String createString(const char* v) { return mono_string_new(domain, v); }
+};
+
+/// @brief ObjectHandle can be used to store reliable reference to MonoObject.
+/// MonoObject can be moved in memory by GC in any time and raw pointer will be invalid. 
+struct ObjectHandle {
+    u32 gc_handle;
+
+    inline ObjectHandle() : gc_handle(0) {}
+
+    inline ObjectHandle(Object obj) {
+        gc_handle = mono_gchandle_new(obj, false);
+    }
+
+    /// implicitly create new ObjectHandle instead
+    inline ObjectHandle(const ObjectHandle& o) = delete;
+
+    inline ObjectHandle(ObjectHandle&& o) {
+        gc_handle = o.gc_handle;
+        o.gc_handle = 0;
+    }
+
+    inline ObjectHandle& operator=(ObjectHandle&& o) {
+        gc_handle = o.gc_handle;
+        o.gc_handle = 0;
+        return *this;
+    }
+
+    inline ~ObjectHandle() {
+        if(gc_handle)
+            mono_gchandle_free(gc_handle);
+    }
+
+    inline Object getObject() const {
+        return mono_gchandle_get_target(gc_handle);
+    }
+};
+
+}

src/Mono/Runtime.cpp

@@ -0,0 +1,30 @@
+#include "mono.hpp"
+#include <mono/jit/jit.h>
+#include <mono/metadata/mono-config.h>
+#include <mono/metadata/appdomain.h>
+
+namespace Mono {
+
+RuntimeJIT::RuntimeJIT(const std::string& domain_name){
+    mono_set_dirs("mono-libs", "mono-libs");
+    mono_set_assemblies_path("mono-libs");
+    mono_config_parse("mono-libs/config.xml");
+
+    domain = mono_jit_init(domain_name.c_str());
+    if(!domain)
+        throw UsefulException("can't initialize mono domain");
+}
+
+RuntimeJIT::~RuntimeJIT(){
+    // TODO: fix segfault on cleanup
+    // mono_jit_cleanup(domain);
+}
+
+std::shared_ptr<Assembly> RuntimeJIT::loadAssembly(const std::string &name){
+    MonoAssembly* ptr = mono_domain_assembly_open(domain, name.c_str());
+    if(!ptr)
+        throw UsefulException(ougge_format("can't load assembly '%s'", name.c_str()));
+    return std::make_shared<Assembly>(ptr);
+}
+
+}

src/Resources/Resources.cpp

@@ -0,0 +1,94 @@
+#include <fstream>
+#include <sstream>
+#include "../common/UsefulException.hpp"
+#include "../common/ougge_format.hpp"
+#include "resources.hpp"
+#include "embedded_resources.h"
+
+
+namespace ougge::resources {
+
+Resource::Resource(const std::string& path, const std::size_t size, StreamFactoryMethod open_read_steam_func)
+  : path(path), size(size), openStream(open_read_steam_func)
+{}
+
+MemoryStreamBuf::MemoryStreamBuf(void* _p, const std::size_t n){
+    char* p=(char*)_p;
+    setg(p, p, p + n);
+    setp(p, p + n);
+}
+
+std::istream::pos_type MemoryStreamBuf::seekoff(
+    std::istream::off_type off,
+    std::ios_base::seekdir dir,
+    std::ios_base::openmode which)
+{
+    if (dir == std::ios_base::cur)
+        gbump(off);
+    else if (dir == std::ios_base::end)
+        setg(eback(), egptr() + off, egptr());
+    else if (dir == std::ios_base::beg)
+        setg(eback(), eback() + off, egptr());
+    return gptr() - eback();
+}
+
+MemoryStreamRead::MemoryStreamRead(const void* p, const std::size_t n)
+    : std::istream(new MemoryStreamBuf((void*)p, n))
+{}
+
+MemoryStreamRead::~MemoryStreamRead(){
+    delete rdbuf();
+}
+
+static std::unordered_map<std::string, Resource>* _resourceMap = nullptr;
+
+void loadEmbeddedresources(){
+    for(int i = 0; i < EmbeddedResource_table_count; i++){
+        const EmbeddedResource& e = EmbeddedResource_table[i];
+        std::cout <<"loading resource '" << e.path << "' " 
+            << formatSizeHumanReadable(e.size) << std::endl;
+        
+        auto embedded_resource_factory = [e]() -> std::unique_ptr<std::istream> { 
+            return std::make_unique<MemoryStreamRead>(e.data, e.size); 
+        };
+
+        auto r = _resourceMap->emplace(e.path, 
+            Resource(e.path, e.size, embedded_resource_factory));
+        if(!r.second)
+            throw UsefulException(ougge_format("can't load duplicate resource '%s'", e.path));
+    }
+}
+
+void init(){
+    if(_resourceMap != nullptr)
+        throw UsefulException("resource has been initialized already");
+    _resourceMap = new std::unordered_map<std::string, Resource>();
+    loadEmbeddedresources();
+}
+
+Resource& getResource(const std::string& path){
+    auto it = _resourceMap->find(path);
+    if(it == _resourceMap->end())
+        throw UsefulException(ougge_format("can't find resource '%s'", path.c_str()));
+    return it->second;
+}
+
+std::string formatSizeHumanReadable(std::size_t b){
+    std::stringstream ss;
+    ss.precision(3);
+    std::size_t k = b / 1024;
+    std::size_t m = k / 1024;
+    std::size_t g = m / 1024;
+    
+    if(g)
+        ss<<m / 1024.0f<<'G';
+    else if(m)
+        ss<<k / 1024.0f<<'M';
+    else if(k)
+        ss<<b / 1024.0f<<'K';
+    else ss<<b;
+
+    return ss.str();
+}
+
+}

src/Resources/Resources.hpp

@@ -0,0 +1,63 @@
+#pragma once
+
+#include "../common/std.hpp"
+#include <iostream>
+#include <functional>
+#include <unordered_map>
+
+namespace ougge::resources {
+
+// call this in main()
+void init();
+
+std::string formatSizeHumanReadable(std::size_t byte_n);
+
+class Resource {
+public:
+    const std::string path;
+    const std::size_t size;
+
+    using StreamFactoryMethod = std::function< std::unique_ptr<std::istream> () >;
+
+    Resource(const std::string& path, const std::size_t size, StreamFactoryMethod open_read_steam_func);
+
+    const StreamFactoryMethod openStream;
+};
+
+class MemoryStreamBuf : public std::streambuf {
+public:
+    MemoryStreamBuf(void* p, const std::size_t n);
+
+    virtual std::istream::pos_type seekoff(
+        std::istream::off_type off,
+        std::ios_base::seekdir dir,
+        std::ios_base::openmode which);
+};
+
+class MemoryStreamRead : public std::istream {
+public:
+    MemoryStreamRead(const void* p, const std::size_t n);
+
+    virtual ~MemoryStreamRead();
+};
+
+Resource& getResource(const std::string& path);
+
+/// @brief stores requested resources in memory
+/// @tparam T must implement constructor `T(const Resource&, ...)`
+template<class T>
+class CacheStorage {
+    std::unordered_map<std::string, T> _map;
+
+public:
+    template<typename... TCtorArgs>
+    T& getOrCreate(const std::string& name, TCtorArgs&&... ctor_args){
+        auto it = _map.find(name);
+        if(it != _map.end())
+            return it->second;
+        auto& res = getResource(name);
+        auto e = _map.emplace(name, T(res, ctor_args...));
+        return e.first->second;
+    }
+};
+}

src/Resources/embedded_resources.h

@@ -0,0 +1,64 @@
+////////////////////////////////////////////////////////////////
+//        This file was generated by resource_embedder        //
+//  https://timerix.ddns.net:3322/Timerix/resource_embedder   //
+////////////////////////////////////////////////////////////////
+//                          USAGE:                            //
+//    Put it in a SOURCE file to define variables             //
+//  #define EMBEDDED_RESOURCE_DEFINITION                      //
+//  #define EMBEDDED_RESOURCE_POSTFIX your_postfix            //
+//  #include "../../src/Resources/embedded_resources.h"       //
+//                                                            //
+//    Put it in a HEADER file to declare external variables   //
+//  #define EMBEDDED_RESOURCE_POSTFIX your_postfix            //
+//  #include "../../src/Resources/embedded_resources.h"       //
+//                                                            //
+//    Then you can access embedded files through              //
+//  EmbeddedResource_table_your_postfix. You can get table    //
+//  content by index and put it into a hashtable or a map.    //
+////////////////////////////////////////////////////////////////
+
+#pragma once
+#if __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stddef.h>
+
+typedef struct {
+    const char* path;
+    const char* data;
+    size_t size;
+} EmbeddedResource;
+
+#define RSCAT(A,B,C...) A##B##C
+#ifdef EMBEDDED_RESOURCE_POSTFIX
+    #define _EmbeddedResource_table(P) \
+        RSCAT(EmbeddedResource_table_, P)
+    #define _EmbeddedResource_table_count(P) \
+        RSCAT(EmbeddedResource_table_, P, _count)
+#else
+    #define _EmbeddedResource_table(P) \
+        EmbeddedResource_table
+    #define _EmbeddedResource_table_count(P) \
+        EmbeddedResource_table_count
+#endif
+extern const EmbeddedResource _EmbeddedResource_table(EMBEDDED_RESOURCE_POSTFIX)[];
+extern const int _EmbeddedResource_table_count(EMBEDDED_RESOURCE_POSTFIX);
+
+#ifdef EMBEDDED_RESOURCE_DEFINITION
+const EmbeddedResource _EmbeddedResource_table(EMBEDDED_RESOURCE_POSTFIX)[]={
+
+};
+
+const int _EmbeddedResource_table_count(EMBEDDED_RESOURCE_POSTFIX)=0;
+#endif // EMBEDDED_RESOURCE_DEFINITION
+
+#undef _EmbeddedResource_table
+#undef _EmbeddedResource_table_count
+#undef EMBEDDED_RESOURCE_POSTFIX
+#undef RSCAT
+
+#if __cplusplus
+}
+#endif

src/Resources/fonts.cpp

@@ -0,0 +1,33 @@
+#include <imgui.h>
+#include "resources.hpp"
+#include <cstdio>
+#include <cstring>
+
+namespace ougge::resources {
+
+// select all glyphs from font
+static const ImWchar glyph_ranges[] = {
+    0x0020, 0xFFFF, 0
+};
+
+ImFont* ImFont_LoadFromFile(const std::string& file_path, f32 font_size, f32 dpi){
+    ImGuiIO& io = ImGui::GetIO();
+    font_size *= dpi;
+    return io.Fonts->AddFontFromFileTTF(file_path.c_str(), font_size, nullptr, glyph_ranges);
+}
+
+ImFont* ImFont_LoadFromResource(const std::string& font_name, f32 font_size, f32 dpi){
+    ImGuiIO& io = ImGui::GetIO();
+    font_size *= dpi;
+    ImFontConfig font_cfg = ImFontConfig();
+    std::sprintf(font_cfg.Name, "%s %ipx", font_name.c_str(), (i32)font_size);
+    
+    auto& res = getResource("fonts/" + font_name + ".ttf");
+    char* font_data = new char[res.size]; 
+    res.openStream()->read(font_data, res.size);
+
+    return io.Fonts->AddFontFromMemoryTTF((void*)(font_data), res.size,
+        font_size, &font_cfg, glyph_ranges);
+}
+
+}

src/Resources/fonts.hpp

@@ -0,0 +1,12 @@
+#pragma once
+
+#include "imgui.h"
+#include "../common/std.hpp"
+
+namespace ougge::resources {
+
+ImFont* ImFont_LoadFromFile(const std::string& file_path, f32 font_size, f32 dpi);
+
+ImFont* ImFont_LoadFromResource(const std::string& font_name, f32 font_size, f32 dpi);
+
+}

src/Resources/textures.cpp

@@ -0,0 +1,96 @@
+#include "textures.hpp"
+#include <SDL_image.h>
+#include "../gui/gui_exceptions.hpp"
+
+namespace ougge::resources {
+
+Texture::Texture(const Resource& r, SDL_Renderer* renderer) 
+    : Texture(*r.openStream(), r.size, renderer)
+{}
+
+Texture::Texture(std::istream& s, size_t size, SDL_Renderer* renderer)
+    : renderer(renderer), texture(nullptr), w(0), h(0)
+{
+    SDL_RWops* sdl_stream = SDL_RWFromIStream(s, size);
+    if(!sdl_stream)
+        throw gui::SDLException();
+    texture = std::shared_ptr<SDL_Texture>(IMG_LoadTexture_RW(renderer, sdl_stream, 1), SDL_DestroyTexture);
+    if(!texture)
+        throw gui::IMGException();
+    SDL_TRY(SDL_QueryTexture(texture.get(), nullptr, nullptr, &w, &h));
+}
+
+SDL_RenderCopyExF_Params::SDL_RenderCopyExF_Params()
+    : rotation_angle(0), flip(SDL_FLIP_NONE) 
+{}
+
+void Texture::render(const SDL_FRect& target_section){
+    SDL_TRY(
+        SDL_RenderCopyF(renderer, texture.get(), nullptr, &target_section)
+    );
+}
+
+void Texture::render(const SDL_FRect& target_section, const SDL_Rect& texture_section){
+    SDL_TRY(
+        SDL_RenderCopyF(renderer, texture.get(), &texture_section, &target_section)
+    );
+}
+
+void Texture::render(const SDL_RenderCopyExF_Params& p){
+    SDL_TRY(
+            SDL_RenderCopyExF(renderer, texture.get(),
+            optional_value_ptr_or_null(p.texture_section),
+            optional_value_ptr_or_null(p.target_section),
+            -1.0f * angleToDegree(normalizeAngle(p.rotation_angle)),
+            optional_value_ptr_or_null(p.rotation_center),
+            p.flip
+        )
+    )
+}
+
+static Sint64 istream_size(SDL_RWops* context){
+    return (Sint64)(size_t)context->hidden.unknown.data2;
+}
+
+static Sint64 istream_seek(SDL_RWops* context, Sint64 offset, i32 whence){
+    std::istream* stream = (std::istream*)context->hidden.unknown.data1;
+    switch(whence){
+        case SEEK_SET: stream->seekg(offset, std::ios::beg); break;
+        case SEEK_CUR: stream->seekg(offset, std::ios::cur); break;
+        case SEEK_END: stream->seekg(offset, std::ios::end); break;
+        default: break;
+    }
+    return stream->fail() ? -1 : (Sint64)stream->tellg();
+}
+
+static size_t istream_read(SDL_RWops* context, void *ptr, size_t size, size_t maxnum){
+    if(size == 0)
+        return -1;
+    std::istream* stream = (std::istream*)context->hidden.unknown.data1;
+    stream->read((char*)ptr, size * maxnum);
+
+    return stream->bad() ? -1 : stream->gcount() / size;
+}
+
+static i32 istream_close(SDL_RWops* context){
+    if (context)
+        SDL_FreeRW(context);
+    return 0;
+}
+
+SDL_RWops* SDL_RWFromIStream(std::istream& stream, size_t size){
+    SDL_RWops* rwops = SDL_AllocRW();
+    if(rwops) {
+        rwops->size = istream_size;
+        rwops->seek = istream_seek;
+        rwops->read = istream_read;
+        rwops->write = nullptr;
+        rwops->close = istream_close;
+        rwops->hidden.unknown.data1 = &stream;
+        rwops->hidden.unknown.data2 = (void*)size;
+        rwops->type = SDL_RWOPS_UNKNOWN;
+    }
+    return rwops;
+}
+
+}

src/Resources/textures.hpp

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <iostream>
+#include <optional>
+#include <SDL.h>
+#include "resources.hpp"
+#include "../common/math.hpp"
+
+namespace ougge::resources {
+
+#define SDL_RectConstruct(X, Y, W, H) (SDL_Rect){X, Y, W, H}
+#define SDL_FRectConstruct(X, Y, W, H) (SDL_FRect){X, Y, W, H}
+#define SDL_PointConstruct(X, Y) (SDL_Point){X, Y, W, H}
+#define SDL_FPointConstruct(X, Y) (SDL_FPoint){X, Y, W, H}
+
+#define optional_value_ptr_or_null(OPT) (OPT ? &(*OPT) : nullptr)
+
+SDL_RWops* SDL_RWFromIStream(std::istream& stream, size_t size);
+
+struct SDL_RenderCopyExF_Params {
+    std::optional<SDL_Rect> texture_section;
+    std::optional<SDL_FRect> target_section;
+    std::optional<SDL_FPoint> rotation_center;
+    angle_t rotation_angle;
+    SDL_RendererFlip flip;
+    
+    SDL_RenderCopyExF_Params();
+};
+
+struct Texture {
+    SDL_Renderer* renderer;
+    std::shared_ptr<SDL_Texture> texture;
+    i32 w;
+    i32 h;
+
+    Texture(const Resource& r, SDL_Renderer* renderer);
+    Texture(std::istream& s, size_t size, SDL_Renderer* renderer);
+
+    void render(const SDL_FRect& target_section);
+    void render(const SDL_FRect& target_section, const SDL_Rect& texture_section);
+    void render(const SDL_RenderCopyExF_Params& params);
+};
+
+}

src/common/UsefulException.hpp

@@ -15,7 +15,7 @@ class UsefulException_ : public std::exception {
 public:
     UsefulException_(const std::string& msg, const std::string& _file, const std::string& _func, int line_n);
 
-    char const* what() const noexcept override;
+    virtual char const* what() const noexcept;
 };
 
 #define useful_assert(EXPR, ERRMSG) if(!(EXPR)) throw UsefulException(ERRMSG);

src/common/function_shared_ptr.hpp

@@ -30,12 +30,13 @@ public:
 
     bool isNull() const { return func_ptr == nullptr; }
 
+    //TODO: make inline
+
     // ReturnT is not void
     template<typename RT = ReturnT>
     std::enable_if_t<!std::is_void<RT>::value, RT>  operator()(ArgTypes... args){
         if(func_ptr == nullptr)
             throw UsefulException("function_shared_ptr is null");
-        //TODO: think about std::forward(args)...
         return func_ptr->operator()(args...);
     }
     

src/common/ougge_format.cpp

@@ -63,22 +63,3 @@ std::string _ougge_format(const std::string& format_str, const size_t args_count
     va_end(vl);
     return ss.str();
 }
-
-
-std::string formatSizeHumanReadable(std::size_t b){
-    std::stringstream ss;
-    ss.precision(3);
-    std::size_t k = b / 1024;
-    std::size_t m = k / 1024;
-    std::size_t g = m / 1024;
-    
-    if(g)
-        ss<<m / 1024.0f<<'G';
-    else if(m)
-        ss<<k / 1024.0f<<'M';
-    else if(k)
-        ss<<b / 1024.0f<<'K';
-    else ss<<b;
-
-    return ss.str();
-}

src/common/ougge_format.hpp

@@ -4,5 +4,3 @@
 
 std::string _ougge_format(const std::string& format_str, const size_t args_count, ...);
 #define ougge_format(FORMAT_STR, ARGS...) _ougge_format(FORMAT_STR, count_args(ARGS) ,##ARGS)
-
-std::string formatSizeHumanReadable(std::size_t byte_n);

src/common/std.hpp

@@ -17,6 +17,7 @@ typedef double f64;
 /// anonymous pointer without specified freeMembers() func
 typedef void* Pointer;
 
+#define nameof(V) #V
 
 #ifdef _MSC_VER
     #pragma comment(lib, "mincore_downlevel.lib") // Support OS older than SDK

src/common/type_name_demangled.hpp

@@ -1,44 +0,0 @@
-// https://stackoverflow.com/a/53865723
-
-#pragma once
-#ifndef _MSC_VER
-    #include <cxxabi.h>
-#endif
-#include <memory>
-#include <string>
-#include <cstdlib>
-
-template <class T>
-std::string _ougge_type_name_demangled()
-{
-    typedef typename std::remove_reference<T>::type TR;
-    const char* type_name_mangled = typeid(TR).name();
-    std::unique_ptr<char, void(*)(void*)> own
-        (
-#ifndef _MSC_VER
-            abi::__cxa_demangle(type_name_mangled, nullptr, nullptr, nullptr),
-#else
-            nullptr,
-#endif
-            std::free
-        );
-    std::string r = own ? own.get() : type_name_mangled;
-    
-    if (std::is_const<TR>::value)
-        r += " const";
-    if (std::is_volatile<TR>::value)
-        r += " volatile";
-    if (std::is_lvalue_reference<T>::value)
-        r += "&";
-    else if (std::is_rvalue_reference<T>::value)
-        r += "&&";
-    
-    return r;
-}
-
-/// @return human-readable type name
-template <class T>
-const std::string& ougge_type_name(){
-    static std::string name = _ougge_type_name_demangled<T>();
-    return name;
-}

src/gui/ErrorWindow.cpp

@@ -0,0 +1,11 @@
+#include "gui.hpp"
+
+namespace ougge::gui {
+
+void drawErrorWindow(const std::string& msg, bool* draw_error_window){
+    ImGui::Begin("ERROR", draw_error_window);
+        ImGui::Text("%s", msg.c_str());
+    ImGui::End();
+}
+
+}

src/gui/MainWindow.cpp

@@ -0,0 +1,218 @@
+#include <backends/imgui_impl_sdl2.h>
+#include <backends/imgui_impl_sdlrenderer2.h>
+#include <iostream>
+#include "MainWindow.hpp"
+#include "gui_exceptions.hpp"
+#include "../common/ougge_format.hpp"
+#include "../resources/fonts.hpp"
+#include "../resources/textures.hpp"
+#include "../common/math.hpp"
+
+namespace ougge::gui {
+
+f32 MainWindow::getDPI(){
+    i32 w=0, h=0;
+    SDL_GetRendererOutputSize(sdl_renderer, &w, &h);
+    i32 sim_w=0, sim_h=0;
+    SDL_GetWindowSize(sdl_window, &sim_w, &sim_h);
+    f32 wdpi=(f32)w / sim_w;
+    f32 hdpi=(f32)h / sim_h;
+    f32 dpi=SDL_sqrtf(wdpi*wdpi + hdpi*hdpi);
+    return dpi;
+}
+
+void MainWindow::open(const std::string& window_title){
+    SDL_TRY(SDL_Init(SDL_INIT_EVERYTHING));
+    SDL_version v;
+    SDL_GetVersion(&v);
+    std::cout<<ougge_format("SDL version: %u.%u.%u\n", v.major, v.minor, v.patch);
+    
+    // From 2.0.18: Enable native IME.
+#ifdef SDL_HINT_IME_SHOW_UI
+    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
+#endif
+    
+    SDL_WindowFlags window_flags = (SDL_WindowFlags)(
+        SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI
+    );
+    sdl_window = SDL_CreateWindow(window_title.c_str(),
+        SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
+        1280, 720, window_flags);
+    if(sdl_window == nullptr)
+        throw SDLException();
+    
+    SDL_RendererFlags renderer_flags = (SDL_RendererFlags)(
+        SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC
+    );
+    sdl_renderer = SDL_CreateRenderer(sdl_window, -1, renderer_flags);
+    if(sdl_renderer == nullptr)
+        throw SDLException();
+    
+    SDL_RendererInfo info;
+    SDL_GetRendererInfo(sdl_renderer, &info);
+    std::cout<<"Current SDL_Renderer driver: "<<info.name<<std::endl;
+
+    // Setup Dear ImGui context
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGuiIO& io = ImGui::GetIO();
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls   
+    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;  // Enable Gamepad Controls
+    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;     // Enable Docking
+    io.ConfigDockingTransparentPayload = true;
+    io.ConfigInputTextCursorBlink = false;
+    // io.ConfigViewportsNoTaskBarIcon = true;
+    io.ConfigWindowsMoveFromTitleBarOnly = true;
+
+    // Setup Platform/Renderer backends
+    if(!ImGui_ImplSDL2_InitForSDLRenderer(sdl_window, sdl_renderer))
+        throw SDLException();
+    if(!ImGui_ImplSDLRenderer2_Init(sdl_renderer))
+        throw SDLException();
+
+    // Setup Dear ImGui style
+    ImGui::StyleColorsDark();
+    f32 dpi = getDPI();
+    io.FontDefault = resources::ImFont_LoadFromResource(default_font, default_font_size, dpi);
+}
+
+void MainWindow::close(){
+    ImGui_ImplSDLRenderer2_Shutdown();
+    ImGui_ImplSDL2_Shutdown();
+    ImGui::DestroyContext();
+    SDL_DestroyRenderer(sdl_renderer);
+    SDL_DestroyWindow(sdl_window);
+    SDL_Quit();
+}
+
+void MainWindow::pollEvents(bool* loopRunning){
+    SDL_Event event;
+    while (SDL_PollEvent(&event)) {
+        ImGui_ImplSDL2_ProcessEvent(&event);
+        switch(event.type){
+            case SDL_QUIT: {
+                *loopRunning = false;
+                break;
+            }
+            case SDL_WINDOWEVENT: {
+                if(event.window.event == SDL_WINDOWEVENT_CLOSE 
+                    && event.window.windowID == SDL_GetWindowID(sdl_window))
+                {
+                    *loopRunning = false;
+                }
+                break;
+            }
+        }
+    }
+}
+
+
+void MainWindow::beginFrame(){
+    // Start the Dear ImGui frame
+    ImGui_ImplSDLRenderer2_NewFrame();
+    ImGui_ImplSDL2_NewFrame();
+    ImGui::NewFrame();
+
+    ImGuiIO& io = ImGui::GetIO();
+    SDL_RenderSetScale(sdl_renderer, io.DisplayFramebufferScale.x, io.DisplayFramebufferScale.y);
+    SDL_SetRenderDrawColor(sdl_renderer, 
+        (u8)(clear_color.x * 255),
+        (u8)(clear_color.y * 255),
+        (u8)(clear_color.z * 255),
+        (u8)(clear_color.w * 255));
+    SDL_RenderClear(sdl_renderer);
+
+    draw_bg_window();
+    draw_debug_window();
+}
+
+void MainWindow::endFrame(){
+    ImGui::Render();
+    ImGui_ImplSDLRenderer2_RenderDrawData(ImGui::GetDrawData(), sdl_renderer);
+    // Swap buffers
+    SDL_RenderPresent(sdl_renderer);
+}
+
+void MainWindow::draw_bg_window(){
+    const ImGuiDockNodeFlags dockspace_flags =
+            ImGuiDockNodeFlags_PassthruCentralNode;
+    const ImGuiWindowFlags window_flags =
+        ImGuiWindowFlags_MenuBar |
+        ImGuiWindowFlags_NoDocking |
+        ImGuiWindowFlags_NoScrollbar |
+        ImGuiWindowFlags_NoScrollWithMouse |
+        ImGuiWindowFlags_NoBringToFrontOnFocus |
+        ImGuiWindowFlags_NoFocusOnAppearing |
+        ImGuiWindowFlags_NoMove |
+        ImGuiWindowFlags_NoResize |
+        ImGuiWindowFlags_NoCollapse |
+        ImGuiWindowFlags_NoTitleBar |
+        ImGuiWindowFlags_NoBackground;
+    // not dockable window that always bound to viewport
+    ImGuiViewport* viewport = ImGui::GetWindowViewport();
+    ImGui::SetNextWindowPos(viewport->Pos, ImGuiCond_Always);
+    ImGui::SetNextWindowSize(viewport->Size, ImGuiCond_Always);
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
+	ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0.0f, 0.0f));
+    ImGui::Begin("bg_window", nullptr, window_flags);
+    ImGui::PopStyleVar(3);
+
+    // DockSpace
+    ImGuiID dockspace_id = ImGui::GetID("bg_dockspace");
+    ImGui::DockSpace(dockspace_id, ImVec2(0.0f, 0.0f), dockspace_flags);
+    
+    // MenuBar
+    if(ImGui::BeginMainMenuBar()){
+        if(ImGui::BeginMenu("test")){
+            if(ImGui::MenuItem("throw exception")){
+                ImGui::EndMenu();
+                ImGui::EndMainMenuBar();
+                ImGui::End();
+                throw UsefulException("example exception");
+            }
+            if(ImGui::MenuItem("throw const char*")){
+                ImGui::EndMenu();
+                ImGui::EndMainMenuBar();
+                ImGui::End();
+                throw "cptr";
+            }
+            if(ImGui::MenuItem("throw std::string")){
+                ImGui::EndMenu();
+                ImGui::EndMainMenuBar();
+                ImGui::End();
+                throw std::string("str");
+            }
+            if(ImGui::MenuItem("throw unknown")){
+                ImGui::EndMenu();
+                ImGui::EndMainMenuBar();
+                ImGui::End();
+                throw 111;
+            }
+            ImGui::EndMenu();
+        }
+        ImGui::EndMainMenuBar();
+    }
+
+    ImGui::End();
+}
+
+void MainWindow::draw_debug_window(){
+    ImGuiIO& io = ImGui::GetIO();
+    if(ImGui::Begin("Debug Options", &show_debug_window)){
+        ImGui::ColorEdit3("clear_color", (float*)&clear_color);
+        ImGui::InputInt("fps_max", &fps_max);
+        ImGui::Text("Application average %.3f ms/frame (%.2f FPS)", 1000.0f / io.Framerate, io.Framerate);
+        ImGui::Checkbox("Demo Window", &show_demo_window);
+        ImGui::Checkbox("Metrics/Debug Window", &show_metrics_window);
+        ImGui::End();
+    }
+
+    if (show_demo_window)
+        ImGui::ShowDemoWindow(&show_demo_window);
+
+    if (show_metrics_window)
+        ImGui::ShowMetricsWindow(&show_metrics_window);
+}
+
+}

src/gui/MainWindow.hpp

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <SDL.h>
+#include <imgui.h>
+#include "../common/std.hpp"
+#include "../common/time.hpp"
+
+/// converts hex color to float vector
+#define RGBAHexToF(R8,G8,B8,A8) ImVec4(((u8)35)/255.0f, ((u8)35)/255.0f, ((u8)50)/255.0f, ((u8)255)/255.0f)
+/// converts float vector to hex color
+#define RGBAFToHex(VEC4) {(u8)(VEC4.x*255), (u8)(VEC4.y*255), (u8)(VEC4.z*255), (u8)(VEC4.w*255)}
+
+namespace ougge::gui {
+
+#define default_font "DroidSans"
+
+class MainWindow {
+public:
+    i32 fps_max = 60;
+    f32 default_font_size = 14.0f;
+    ImVec4 clear_color = RGBAHexToF(35,35,50,255);
+    SDL_Window* sdl_window = nullptr;
+    SDL_Renderer* sdl_renderer = nullptr;
+
+private:
+    bool show_debug_window = true;
+    bool show_demo_window = false;
+    bool show_metrics_window = false;
+
+public:
+    void open(const std::string& window_title);
+    void close();
+
+    /// process io events happened since previous frame
+    void pollEvents(bool* loopRunning);
+    void beginFrame();
+    void endFrame();
+
+    f32 getDPI();
+private:
+    void draw_debug_window();
+    void draw_bg_window();
+};
+
+}

src/gui/gui.hpp

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <SDL.h>
+#include <imgui.h>
+#include "gui_exceptions.hpp"
+
+namespace ougge::gui {
+
+void drawErrorWindow(const std::string& msg, bool* draw_error_window);
+
+}

src/main.cpp

@@ -1,67 +1,47 @@
 #define SDL_MAIN_HANDLED
 #include <iostream>
 #include <iomanip>
+#include "common/UsefulException.hpp"
+#include "common/ougge_format.hpp"
 #include "Engine.hpp"
-#include "modules/MainWindowSDL2.hpp"
+#include "gui/gui.hpp"
-#include "modules/MonoGameObjectSystem.hpp"
-#include "resources/textures.hpp"
 
 using namespace ougge;
 
-class TutelModule : public IEngineModule {
+void drawTutel(Engine& engine){
-    resources::CacheStorage<resources::Texture> textures;
+    resources::Texture& tutel = engine.textures.getOrCreate("tutel.png", engine.mainWindow.sdl_renderer);
-public:
+    resources::SDL_RenderCopyExF_Params params;
-    TutelModule(Engine& engine, resources::ResourceManager& resourceManager) :
+    params.target_section = SDL_FRectConstruct(100, 100, 400, 400);
-        IEngineModule(engine),
+    static i32 si = 1;
-        textures(&resourceManager)
+    params.rotation_angle = M_PI_4 * (si++ / engine.mainWindow.fps_max);
-    {
+    tutel.render(params);
-        //TODO: add something like `assert(requireModule(MainWindow))`
-    }
-
-    const std::string& getName() override {
-        return ougge_type_name<TutelModule>();
-    }
-
-    void beginFrame() override {
-        auto& mainWindow = engine.getModule<modules::MainWindowSDL2>();
-        resources::Texture* tutel = textures.tryGetOrCreate("tutel.png", mainWindow.sdl_renderer);
-        if(tutel == nullptr){
-            throw new UsefulException("couldn't find resource 'tutel.png'");
-        }
-        resources::SDL_RenderCopyExF_Params params;
-        params.target_section = SDL_FRectConstruct(100, 100, 400, 400);
-        static i32 si = 1;
-        params.rotation_angle = M_PI_4 * (si++ / engine.fps_max);
-        tutel->render(params);
-    }
-
-};
-
-void createExampleObject(Engine& engine){
-    std::cout<<"creating ExampleObject"<<std::endl;
-    auto& monoSystem = engine.getModule<modules::MonoGameObjectSystem>();
-    game::GameObject& exampleObj = monoSystem.createGameObject();
-    std::string componentClassName = "Ougge.ExampleComponent";
-    if(!monoSystem.tryCreateComponent(exampleObj, componentClassName))
-        throw UsefulException(ougge_format("couldn't create component '%s'", componentClassName.c_str()));
 }
 
 int main(int argc, const char** argv){
     try {
-        std::cout<<"Initializing Engine"<<std::endl;
+        resources::init();
+        std::cout<<"initialized resource loader"<<std::endl;
+        
         Engine engine;
+        std::cout<<"initialized mono jit runtime"<<std::endl;
+        engine.init();
+        std::cout<<"initialized game engine"<<std::endl;
         
-        std::cout<<"Initializing ResourceManager"<<std::endl;
+        game::GameObject& exampleObj = engine.createGameObject();
-        resources::ResourceManager resourceManager;
+        std::string componentClassName = "Ougge.ExampleComponent";
+        if(!engine.tryCreateComponent(exampleObj, componentClassName))
+            throw UsefulException(ougge_format("couldn't create component '%s'", componentClassName.c_str()));
         
-        engine.createModule<modules::MainWindowSDL2>("ougge", resourceManager);
+        std::cout<<"created ExampleObject"<<std::endl;
-        engine.createModule<modules::MonoGameObjectSystem>(64*1024);
-        createExampleObject(engine);
-        engine.createModule<TutelModule>(resourceManager);
         
-        std::cout<<"main loop start"<<std::endl;
+        engine.updateCallback = [&engine](f64 deltaTime) -> void {
+            drawTutel(engine);
+        };
+        
+        engine.openMainWindow("ougge");
+        std::cout<<"created sdl window"<<std::endl;
         engine.startLoop();
-        std::cout<<"main loop stop"<<std::endl;
+        std::cout<<"sdl window has been cosed"<<std::endl;
     }
     catch(const std::exception& e){
         std::cerr<<"Catched exception: "<<e.what()<<std::endl;

src/modules/MonoGameObjectSystem.cpp

@@ -1,39 +0,0 @@
-#include "MonoGameObjectSystem.hpp"
-
-namespace ougge::modules {
-
-const std::string& MonoGameObjectSystem::getName() {
-    return ougge_type_name<MonoGameObjectSystem>();
-}
-
-MonoGameObjectSystem::MonoGameObjectSystem(Engine& engine, u32 max_game_objects) :
-    IEngineModule(engine), 
-    gameObjectPool(max_game_objects)
-{
-    engineManagedAssembly = mono.loadAssembly("Ougge.dll");
-    gameObjectClass = engineManagedAssembly->getClass("Ougge", "GameObject");
-    gameObjectCtor = Mono::Method<void(u64, u32)>(gameObjectClass, ".ctor");
-    gameObjectInvokeUpdate = Mono::Method<void(f64)>(gameObjectClass, "InvokeUpdate");
-    gameObjectTryCreateComponent = Mono::Method<Mono::Bool(Mono::String)>(gameObjectClass, "TryCreateComponent_internal");
-}
-
-void MonoGameObjectSystem::beginFrame(){
-    for(auto pair : gameObjectPool){
-        gameObjectInvokeUpdate(pair.second.getObjectHandle().getObject(), engine.deltaTime);
-    }
-}
-
-game::GameObject& MonoGameObjectSystem::createGameObject(){
-    auto pair = gameObjectPool.emplace(game::GameObject(mono.createObject(gameObjectClass)));
-    game::GameObject& obj = pair.second;
-    gameObjectCtor(obj.getObjectHandle().getObject(), ++obj_id, pair.first);
-    return obj;
-}
-
-bool MonoGameObjectSystem::tryCreateComponent(game::GameObject& obj, const std::string& componentClassName){
-    Mono::String componentClassNameManaged = mono.createString(componentClassName);
-    Mono::Bool created = gameObjectTryCreateComponent(obj.getObjectHandle().getObject(), componentClassNameManaged);
-    return created.wide_bool;
-}
-
-}

src/modules/MonoGameObjectSystem.hpp

@@ -1,31 +0,0 @@
-#pragma once
-
-#include "../Engine.hpp"
-#include "../common/function_shared_ptr.hpp"
-#include "../mono/mono.hpp"
-#include "../game/GameObjectPool.hpp"
-
-namespace ougge::modules {
-
-class MonoGameObjectSystem : public IEngineModule {
-    Mono::RuntimeJIT mono;
-    game::GameObjectPool gameObjectPool;
-    u64 obj_id = 0;
-    MonoClass* gameObjectClass;
-    Mono::Method<void(u64, u32)> gameObjectCtor;
-    Mono::Method<void(f64)> gameObjectInvokeUpdate;
-    Mono::Method<Mono::Bool(Mono::String)> gameObjectTryCreateComponent;
-
-public:
-    std::shared_ptr<Mono::Assembly> engineManagedAssembly;
-
-    MonoGameObjectSystem(Engine& engine, u32 max_game_objects);
-    
-    const std::string& getName() override;
-    void beginFrame() override;
-    
-    game::GameObject& createGameObject();
-    bool tryCreateComponent(game::GameObject& obj, const std::string& componentClassName);
-};
-
-}

src/resources/MemorySteam.cpp

@@ -1,40 +0,0 @@
-#include "MemoryStream.hpp"
-
-class MemoryStreamBuf : public std::streambuf {
-public:
-    MemoryStreamBuf(void* p, const std::size_t n);
-
-    std::istream::pos_type seekoff(
-        std::istream::off_type off,
-        std::ios_base::seekdir dir,
-        std::ios_base::openmode which) override;
-};
-
-MemoryStreamBuf::MemoryStreamBuf(void* _p, const std::size_t n){
-    char* p=(char*)_p;
-    setg(p, p, p + n);
-    setp(p, p + n);
-}
-
-std::istream::pos_type MemoryStreamBuf::seekoff(
-    std::istream::off_type off,
-    std::ios_base::seekdir dir,
-    std::ios_base::openmode which)
-{
-    if (dir == std::ios_base::cur)
-        gbump(off);
-    else if (dir == std::ios_base::end)
-        setg(eback(), egptr() + off, egptr());
-    else if (dir == std::ios_base::beg)
-        setg(eback(), eback() + off, egptr());
-    return gptr() - eback();
-}
-
-
-MemoryStreamRead::MemoryStreamRead(const void* p, const std::size_t n)
-    : std::istream(new MemoryStreamBuf((void*)p, n))
-{}
-
-MemoryStreamRead::~MemoryStreamRead(){
-    delete rdbuf();
-}

src/resources/MemoryStream.hpp

@@ -1,8 +0,0 @@
-#include <iostream>
-
-class MemoryStreamRead : public std::istream {
-public:
-    MemoryStreamRead(const void* p, const std::size_t n);
-
-    virtual ~MemoryStreamRead();
-};

src/resources/fonts.cpp

@@ -1,4 +1,7 @@
-#include "fonts.hpp"
+#include <imgui.h>
+#include "resources.hpp"
+#include <cstdio>
+#include <cstring>
 
 namespace ougge::resources {
 
@@ -13,16 +16,17 @@ ImFont* ImFont_LoadFromFile(const std::string& file_path, f32 font_size, f32 dpi
     return io.Fonts->AddFontFromFileTTF(file_path.c_str(), font_size, nullptr, glyph_ranges);
 }
 
-ImFont* ImFont_LoadFromResource(ResourceFactory* res, f32 font_size, f32 dpi){
+ImFont* ImFont_LoadFromResource(const std::string& font_name, f32 font_size, f32 dpi){
     ImGuiIO& io = ImGui::GetIO();
     font_size *= dpi;
     ImFontConfig font_cfg = ImFontConfig();
-    std::sprintf(font_cfg.Name, "%s %ipx", res->path.c_str(), (i32)font_size);
+    std::sprintf(font_cfg.Name, "%s %ipx", font_name.c_str(), (i32)font_size);
     
-    char* font_data = new char[res->size]; 
+    auto& res = getResource("fonts/" + font_name + ".ttf");
-    res->openStream()->read(font_data, res->size);
+    char* font_data = new char[res.size]; 
+    res.openStream()->read(font_data, res.size);
 
-    return io.Fonts->AddFontFromMemoryTTF((void*)(font_data), res->size,
+    return io.Fonts->AddFontFromMemoryTTF((void*)(font_data), res.size,
         font_size, &font_cfg, glyph_ranges);
 }
 

src/resources/fonts.hpp

@@ -1,13 +1,12 @@
 #pragma once
 
-#include <imgui.h>
+#include "imgui.h"
 #include "../common/std.hpp"
-#include "resources.hpp"
 
 namespace ougge::resources {
 
 ImFont* ImFont_LoadFromFile(const std::string& file_path, f32 font_size, f32 dpi);
 
-ImFont* ImFont_LoadFromResource(ResourceFactory* res, f32 font_size, f32 dpi);
+ImFont* ImFont_LoadFromResource(const std::string& font_name, f32 font_size, f32 dpi);
 
 }

src/resources/resources.cpp

@@ -4,22 +4,45 @@
 #include "../common/ougge_format.hpp"
 #include "resources.hpp"
 #include "embedded_resources.h"
-#include "MemoryStream.hpp"
+
 
 namespace ougge::resources {
 
-ResourceFactory::ResourceFactory(const std::string& path, const std::size_t size, StreamFactoryMethod open_read_steam_func)
+Resource::Resource(const std::string& path, const std::size_t size, StreamFactoryMethod open_read_steam_func)
   : path(path), size(size), openStream(open_read_steam_func)
 {}
 
+MemoryStreamBuf::MemoryStreamBuf(void* _p, const std::size_t n){
+    char* p=(char*)_p;
+    setg(p, p, p + n);
+    setp(p, p + n);
+}
 
-std::shared_ptr<ResourceMap> ResourceManager::_embeddedResourcesMap;
+std::istream::pos_type MemoryStreamBuf::seekoff(
+    std::istream::off_type off,
+    std::ios_base::seekdir dir,
+    std::ios_base::openmode which)
+{
+    if (dir == std::ios_base::cur)
+        gbump(off);
+    else if (dir == std::ios_base::end)
+        setg(eback(), egptr() + off, egptr());
+    else if (dir == std::ios_base::beg)
+        setg(eback(), eback() + off, egptr());
+    return gptr() - eback();
+}
 
-void ResourceManager::loadEmbeddedResources(){
+MemoryStreamRead::MemoryStreamRead(const void* p, const std::size_t n)
-    if(_embeddedResourcesMap != nullptr)
+    : std::istream(new MemoryStreamBuf((void*)p, n))
-        return;
+{}
 
-    _embeddedResourcesMap = std::make_shared<ResourceMap>();
+MemoryStreamRead::~MemoryStreamRead(){
+    delete rdbuf();
+}
+
+static std::unordered_map<std::string, Resource>* _resourceMap = nullptr;
+
+void loadEmbeddedresources(){
     for(int i = 0; i < EmbeddedResource_table_count; i++){
         const EmbeddedResource& e = EmbeddedResource_table[i];
         std::cout <<"loading resource '" << e.path << "' " 
@@ -29,36 +52,43 @@ void ResourceManager::loadEmbeddedResources(){
             return std::make_unique<MemoryStreamRead>(e.data, e.size); 
         };
 
-        auto r = _embeddedResourcesMap->emplace(e.path, 
+        auto r = _resourceMap->emplace(e.path, 
-            ResourceFactory(e.path, e.size, embedded_resource_factory));
+            Resource(e.path, e.size, embedded_resource_factory));
         if(!r.second)
             throw UsefulException(ougge_format("can't load duplicate resource '%s'", e.path));
     }
-    
-    _resourceMaps.push_back(_embeddedResourcesMap);
 }
 
-ResourceManager::ResourceManager(){
+void init(){
-    loadEmbeddedResources();
+    if(_resourceMap != nullptr)
+        throw UsefulException("resource has been initialized already");
+    _resourceMap = new std::unordered_map<std::string, Resource>();
+    loadEmbeddedresources();
 }
 
-ResourceFactory* ResourceManager::tryGetResource(const std::string& path){
+Resource& getResource(const std::string& path){
-    // reverse iteration of linked list
+    auto it = _resourceMap->find(path);
-    auto map_list_iterator = _resourceMaps.end();
+    if(it == _resourceMap->end())
-    while(map_list_iterator != _resourceMaps.begin()){
+        throw UsefulException(ougge_format("can't find resource '%s'", path.c_str()));
-        --map_list_iterator;
+    return it->second;
-        auto map = *map_list_iterator;
+}
 
-        auto resource_iterator = map->find(path);
+std::string formatSizeHumanReadable(std::size_t b){
+    std::stringstream ss;
+    ss.precision(3);
+    std::size_t k = b / 1024;
+    std::size_t m = k / 1024;
+    std::size_t g = m / 1024;
     
-        // resource not found
+    if(g)
-        if(resource_iterator == map->end())
+        ss<<m / 1024.0f<<'G';
-            return nullptr;
+    else if(m)
+        ss<<k / 1024.0f<<'M';
+    else if(k)
+        ss<<b / 1024.0f<<'K';
+    else ss<<b;
 
-        return &resource_iterator->second;
+    return ss.str();
-    }
-
-    return nullptr;
 }
 
 }

src/resources/resources.hpp

@@ -4,72 +4,60 @@
 #include <iostream>
 #include <functional>
 #include <unordered_map>
-#include <memory>
-#include <list>
 
 namespace ougge::resources {
 
-class ResourceFactory {
+// call this in main()
+void init();
+
+std::string formatSizeHumanReadable(std::size_t byte_n);
+
+class Resource {
 public:
     const std::string path;
     const std::size_t size;
 
     using StreamFactoryMethod = std::function< std::unique_ptr<std::istream> () >;
 
-    ResourceFactory(const std::string& path, const std::size_t size, StreamFactoryMethod open_read_steam_func);
+    Resource(const std::string& path, const std::size_t size, StreamFactoryMethod open_read_steam_func);
 
     const StreamFactoryMethod openStream;
 };
 
-using ResourceMap = std::unordered_map<std::string, ResourceFactory>;
+class MemoryStreamBuf : public std::streambuf {
-
-//TODO: rewrite ResourceManager as a module
-class ResourceManager {
-    std::list<std::shared_ptr<ResourceMap>> _resourceMaps;
-    static std::shared_ptr<ResourceMap> _embeddedResourcesMap;
-    void loadEmbeddedResources();
-
 public:
-    ResourceManager();
+    MemoryStreamBuf(void* p, const std::size_t n);
 
-    void addResourceMap(std::shared_ptr<ResourceMap> m);
+    virtual std::istream::pos_type seekoff(
-    
+        std::istream::off_type off,
-    std::shared_ptr<ResourceMap> loadResouceMap();
+        std::ios_base::seekdir dir,
-    void removeResourceMap();
+        std::ios_base::openmode which);
-
-    ResourceFactory* tryGetResource(const std::string& path);
 };
 
+class MemoryStreamRead : public std::istream {
+public:
+    MemoryStreamRead(const void* p, const std::size_t n);
+
+    virtual ~MemoryStreamRead();
+};
+
+Resource& getResource(const std::string& path);
+
 /// @brief stores requested resources in memory
-/// @tparam T must implement constructor `T(ResourceFactory*, ...)`
+/// @tparam T must implement constructor `T(const Resource&, ...)`
 template<class T>
 class CacheStorage {
     std::unordered_map<std::string, T> _map;
-    ResourceManager* _resourceManager;
 
 public:
-    CacheStorage(ResourceManager*);
-    CacheStorage(CacheStorage&&) = delete;
-    CacheStorage(const CacheStorage&) = delete;
-
     template<typename... TCtorArgs>
-    T* tryGetOrCreate(const std::string& name, TCtorArgs&&... ctor_args){
+    T& getOrCreate(const std::string& name, TCtorArgs&&... ctor_args){
         auto it = _map.find(name);
         if(it != _map.end())
-            return &it->second;
+            return it->second;
-        
+        auto& res = getResource(name);
-        ResourceFactory* res = _resourceManager->tryGetResource(name);
-        if(res == nullptr)
-            return nullptr;
-        
         auto e = _map.emplace(name, T(res, ctor_args...));
-        return &e.first->second;
+        return e.first->second;
     }
 };
-
-
-template <class T> inline CacheStorage<T>::CacheStorage(ResourceManager* resourceManager)
-    : _resourceManager(resourceManager)
-{}
-
 }

src/resources/textures.cpp

@@ -4,8 +4,8 @@
 
 namespace ougge::resources {
 
-Texture::Texture(ResourceFactory* r, SDL_Renderer* renderer) 
+Texture::Texture(const Resource& r, SDL_Renderer* renderer) 
-    : Texture(*r->openStream(), r->size, renderer)
+    : Texture(*r.openStream(), r.size, renderer)
 {}
 
 Texture::Texture(std::istream& s, size_t size, SDL_Renderer* renderer)

src/resources/textures.hpp

@@ -33,7 +33,7 @@ struct Texture {
     i32 w;
     i32 h;
 
-    Texture(ResourceFactory* r, SDL_Renderer* renderer);
+    Texture(const Resource& r, SDL_Renderer* renderer);
     Texture(std::istream& s, size_t size, SDL_Renderer* renderer);
 
     void render(const SDL_FRect& target_section);