# GroveEngine - Framework C++ Modulaire

**Status**: WIP
**Type**: Game Engine Framework
**Stack**: C++17, bgfx, SDL2, nlohmann_json, spdlog
**Location**: `C:\Users\alexi\Documents\projects\groveengine`
**Core Status**: Validé, Rendering en développement
**Moved to WIP**: 30 novembre 2025
**Dernière activité**: 29 novembre 2025 (46 commits sur 3 semaines)

---

## Vue d'ensemble

**GroveEngine** est un moteur de jeu C++17 modulaire conçu pour :

- **Hot-reload ultra-rapide** : 0.4ms validé (5000x plus rapide qu'un cycle edit-build-test classique)
- **AI-optimized** : Micro-modules (200-300 lignes) parfaits pour développement assisté Claude
- **Scalabilité transparente** : Du debug local au cluster distribué sans modifier le code modules
- **Data-driven** : Config/YAML/JSON pour tout le contenu (LLM peut créer sans toucher C++)

**Nom** : "Grove" = bosquet où les modules poussent comme des arbres indépendants.

---

## Architecture Core

### Philosophie : 13 Interfaces

L'architecture repose sur **13 interfaces abstraites** permettant de swap les implémentations sans modifier le code métier.

```
┌─────────────────────────────────────────────────────────────┐
│  Application (ex: aissia-core.exe, warfactory.exe)          │
│  └─ main() → EngineFactory::create()                        │
└──────────────────────────┬──────────────────────────────────┘
                           │
                           ▼
┌─────────────────────────────────────────────────────────────┐
│  IEngine (orchestration)                                     │
│  ├─ IModuleSystem (stratégie d'exécution)                   │
│  ├─ IIO (communication pub/sub)                              │
│  ├─ IDataTree (configuration hiérarchique)                   │
│  └─ Game loop                                                │
└──────────────────────────┬──────────────────────────────────┘
                           │
                           ▼
┌─────────────────────────────────────────────────────────────┐
│  Modules (DLL/SO hot-reloadable, 200-300 lignes chacun)     │
│  ├─ module_a.dll → IModule::process()                        │
│  ├─ module_b.dll → IModule::process()                        │
│  └─ module_c.dll → IModule::process()                        │
│      Communication via IIO (pub/sub topics)                  │
└─────────────────────────────────────────────────────────────┘
```

### Les 13 Interfaces

| Interface | Rôle | Implémentations |
|-----------|------|-----------------|
| **IEngine** | Orchestration système, main loop | DebugEngine ✅, HighPerfEngine (planned), DataOrientedEngine (planned) |
| **IModule** | Logique métier (micro-modules) | Custom modules (.dll/.so) |
| **IModuleSystem** | Stratégie d'exécution modules | SequentialModuleSystem ✅, ThreadedModuleSystem (planned), ClusterModuleSystem (planned) |
| **IIO** | Communication pub/sub | IntraIO ✅ (même process), LocalIO (planned), NetworkIO (planned) |
| **IDataTree** | Racine configuration | JsonDataTree ✅ |
| **IDataNode** | Noeud configuration | JsonDataNode ✅ |
| **ITaskScheduler** | Délégation tâches async | (planned) |
| **IUI** | Abstraction UI | ImGuiUI ✅ |
| **ISerializable** | Sérialisation état | JSON-based |
| **ICoordinationModule** | Coordination inter-modules | (planned) |

### Scalabilité Transparente

```
MVP Debug:      DebugEngine + SequentialModuleSystem + IntraIO
                (Single-thread, même process, logging verbose)

Production:     HighPerfEngine + ThreadedModuleSystem + LocalIO
                (Multi-thread, named pipes/sockets)

Cloud/MMO:      DataOrientedEngine + ClusterModuleSystem + NetworkIO
                (Distribué, TCP/WebSocket)
```

**Aucun changement de code dans les modules** - Juste swap des implémentations via config.

---

## Hot-Reload System

### Performance Validée

| Métrique | Valeur |
|----------|--------|
| **Temps moyen** | 0.4ms |
| **Meilleur cas** | 0.055ms |
| **State preservation** | 100% (via ISerializable) |
| **Commit validation** | fc28009 (24 Sept 2025) |

### Mécanisme

```cpp
// 1. Détection changement fichier DLL
if (filesystem::last_write_time("module.dll") > last_load_time) {

    // 2. Sauvegarder état via ISerializable
    nlohmann::json state;
    old_module->serialize(state);

    // 3. Shutdown module actuel
    old_module->shutdown();

    // 4. Unload DLL
    #ifdef _WIN32
        FreeLibrary(dll_handle);
    #else
        dlclose(dll_handle);
    #endif

    // 5. Reload nouvelle DLL
    #ifdef _WIN32
        dll_handle = LoadLibrary("module.dll");
    #else
        dll_handle = dlopen("./module.so", RTLD_NOW);
    #endif

    // 6. Initialize nouveau module avec état restauré
    new_module->initialize(config, io);
    new_module->deserialize(state);

    // Total: 0.4ms
}
```

### Interface IModule

```cpp
class IModule {
public:
    virtual ~IModule() = default;

    // Lifecycle
    virtual void initialize(const IDataNode& config, IIO* io) = 0;
    virtual void process(float dt) = 0;
    virtual void shutdown() = 0;

    // Hot-reload state preservation
    virtual nlohmann::json getState() const = 0;
    virtual void setState(const nlohmann::json& state) = 0;

    // Metadata
    virtual std::string getName() const = 0;
    virtual int getVersion() const = 0;
    virtual std::vector<std::string> getDependencies() const = 0;
};
```

### Contraintes Micro-Modules

- **200-300 lignes max** par module (AI-friendly)
- **Zero parent dependencies** : Pas de `#include "../"`
- **JSON-only inter-module** : Communication via IIO topics
- **Build autonome** : `cmake .` depuis le dossier module

---

## Communication Inter-Modules (IIO)

### TopicTree : Pub/Sub Ultra-Rapide

**Bibliothèque interne** : StillHammer::topictree
**Performance** : O(k) où k = profondeur topic (pas O(n) patterns)

```cpp
// Publisher (Module A)
io->publish("game/player/position", position_json);
io->publish("game/enemy/42/health", health_json);

// Subscriber (Module B) - Wildcards supportés
io->subscribe("game/player/*", [](const Message& msg) {
    // Reçoit tous les messages player
});

io->subscribe("game/enemy/+/health", [](const Message& msg) {
    // + = single level wildcard
    // Reçoit health de tous les enemies
});
```

### Performance TopicTree

| Patterns | Temps matching |
|----------|----------------|
| 1,000 | < 1ms |
| 10,000 | < 5ms |

### Design Pull-Based

- **Synchrone** : Messages collectés, traités en batch
- **Low-frequency** : Optimisé pour 60 FPS game loop, pas high-frequency trading
- **Découplage total** : Modules ignorent l'existence des autres

---

## Data System (IDataTree / IDataNode)

### Configuration Hiérarchique Type-Safe

```cpp
// Lecture config
void MyModule::initialize(const IDataNode& config, IIO* io) {
    int width = config.get("window.width", 1280);
    std::string title = config.get("window.title", "GroveEngine");
    bool vsync = config.get("rendering.vsync", true);

    // Navigation arbre
    auto& enemies = config.getChild("enemies");
    for (const auto& enemy : enemies.getChildren()) {
        std::string type = enemy.get("type", "basic");
        int hp = enemy.get("hp", 100);
    }
}
```

### Backed by JSON Files

```json
{
  "window": {
    "width": 1280,
    "height": 720,
    "title": "My Game"
  },
  "rendering": {
    "vsync": true,
    "clear_color": "#303030"
  },
  "enemies": [
    {"type": "basic", "hp": 100},
    {"type": "heavy", "hp": 500}
  ]
}
```

---

## Structure Projet

```
GroveEngine/
├── include/grove/           # 32 headers (interfaces + impls)
│   ├── IEngine.h
│   ├── IModule.h
│   ├── IModuleSystem.h
│   ├── IIO.h
│   ├── IDataTree.h
│   ├── IDataNode.h
│   ├── ITaskScheduler.h
│   ├── IUI.h
│   ├── ISerializable.h
│   └── ...
│
├── src/                     # Implémentations concrètes
│   ├── DebugEngine.cpp
│   ├── SequentialModuleSystem.cpp
│   ├── IntraIO.cpp
│   ├── IntraIOManager.cpp
│   ├── JsonDataNode.cpp
│   ├── JsonDataTree.cpp
│   ├── ModuleFactory.cpp
│   ├── EngineFactory.cpp
│   └── ...
│
├── modules/                 # Modules hot-reloadables
│   └── BgfxRenderer/        # Module rendering 2D (WIP)
│       ├── BgfxRendererModule.cpp
│       ├── RHI/             # Render Hardware Interface
│       ├── Shaders/         # Pre-compiled (GL/Vulkan/DX11/Metal)
│       ├── Passes/          # Clear, Sprite, Debug
│       ├── RenderGraph/     # Dependency ordering
│       └── Scene/           # Message collection from IIO
│
├── external/StillHammer/    # Libs internes
│   ├── topictree/           # O(k) topic matching
│   └── logger/              # spdlog wrapper
│
├── tests/                   # Test suite (Catch2)
│   ├── benchmarks/
│   ├── hotreload/
│   └── helpers/
│
├── docs/                    # Documentation
│   ├── architecture/
│   ├── implementation/
│   └── plans/
│
└── CMakeLists.txt          # Build system
```

---

## Module Rendering (BgfxRenderer)

### Stack Rendering

- **bgfx** : Abstraction multi-backend (Vulkan/DX12/Metal/OpenGL)
- **SDL2** : Window + input management
- **stb_image** : Texture loading

### Architecture RenderModule

```cpp
class BgfxRendererModule : public grove::IModule {
public:
    // IModule interface
    void initialize(const IDataNode& config, IIO* io) override;
    void process(float dt) override;
    void shutdown() override;

    // Rendering API (via IIO messages)
    // Autres modules publient sur "render/sprite", "render/rect", etc.
    // BgfxRenderer subscribe et render tout en batch

private:
    SDL_Window* window;
    bgfx::ViewId main_view;

    // Render passes
    ClearPass clear_pass;
    SpritePass sprite_pass;
    DebugPass debug_pass;

    // Scene collector (from IIO)
    SceneCollector scene;
};
```

### Rendering Pipeline

```cpp
void BgfxRendererModule::process(float dt) {
    // 1. Collecter messages rendering depuis IIO
    scene.CollectFromIO(io);

    // 2. Exécuter passes
    clear_pass.Execute(main_view);
    sprite_pass.Execute(main_view, scene.sprites);
    debug_pass.Execute(main_view, scene.debug_shapes);

    // 3. Submit frame
    bgfx::frame();

    // 4. Clear scene pour prochain frame
    scene.Clear();
}
```

### Shaders Pre-Compilés

Shaders compilés pour tous backends via `shaderc` :

```
Shaders/
├── vs_sprite.bin.gl      # OpenGL
├── vs_sprite.bin.vk      # Vulkan
├── vs_sprite.bin.dx11    # DirectX 11
├── vs_sprite.bin.mtl     # Metal
├── fs_sprite.bin.gl
├── fs_sprite.bin.vk
├── fs_sprite.bin.dx11
└── fs_sprite.bin.mtl
```

### Camera 2D

```cpp
class Camera2D {
public:
    Vec2 position{0, 0};
    float zoom = 1.0f;

    Mat4 GetViewMatrix() const {
        return Mat4::Translation(-position.x, -position.y, 0);
    }

    Mat4 GetProjectionMatrix(int width, int height) const {
        float halfW = (width / zoom) * 0.5f;
        float halfH = (height / zoom) * 0.5f;
        return Mat4::Ortho(-halfW, halfW, -halfH, halfH, -1, 1);
    }
};
```

---

## Architecture AI-Friendly (Data-Driven)

### Principe

**LLM peut créer/modifier game content sans toucher au code C++.**

### Entity System (YAML)

```yaml
# entities/wagons/wagon_armored.yaml
entity: wagon_armored
components:
  - type: visual
    sprite: wagon_armored.png
    size: [20, 6]

  - type: balance
    weight: 7.5
    center_of_mass: [10, 3]

  - type: health
    hp_max: 200
    armor: 50

  - type: slots
    grid: [20, 6]
    specialization: military
```

### UI Layouts (JSON)

```json
{
  "screen": "train_builder",
  "elements": [
    {
      "type": "panel",
      "id": "wagon_view",
      "rect": [0, 0, 800, 600],
      "background": "#2a2a2a"
    },
    {
      "type": "gauge",
      "id": "balance_lateral",
      "rect": [820, 20, 160, 40],
      "label": "Balance G/D",
      "value_binding": "wagon.balance.lateral"
    }
  ]
}
```

### Missions/Events (YAML)

```yaml
mission:
  id: scavenge_kyiv
  name: "Colonne russe détruite"
  difficulty: easy

  rewards:
    metal: [50, 100]
    electronics: [20, 40]

  events:
    - trigger: mission_start
      choices:
        - id: approach_cautious
          text: "Approche prudente"
          risk_modifier: -0.5
        - id: rush
          text: "Rush rapide"
          risk_modifier: +0.8
```

### Asset Manifests (TOML)

```toml
[wagon_armored]
file = "textures/wagon_armored.png"
size = [400, 120]
pivot = [200, 60]
tags = ["wagon", "armored", "heavy"]
weight_modifier = 1.5
```

---

## Dépendances

### Core (FetchContent CMake)

| Library | Version | Usage |
|---------|---------|-------|
| **nlohmann_json** | 3.11.3 | JSON processing |
| **spdlog** | 1.12.0 | Logging |
| **Catch2** | 3.5+ | Testing |

### Rendering (Optionnel)

| Library | Usage |
|---------|-------|
| **bgfx** | Multi-backend rendering |
| **bx** | Base library (bgfx dep) |
| **bimg** | Image loading (bgfx dep) |
| **SDL2** | Windowing + input |
| **stb_image** | Texture loading |

### Internal (StillHammer)

| Library | Usage |
|---------|-------|
| **topictree** | O(k) pub/sub topic matching |
| **logger** | Domain-organized spdlog wrapper |

### Optionnel Futur

| Library | Usage |
|---------|-------|
| **yaml-cpp** | YAML parsing (entities) |
| **TOML++** | Config files |
| **ImGui** | Debug UI |
| **Lua** | Scripting (si nécessaire) |
| **stb_truetype** / **FreeType** | Font rendering |

---

## Build System

### CMake Options

```cmake
# Core
GROVE_BUILD_IMPLEMENTATIONS  # Compile implémentations core
GROVE_BUILD_TESTS            # Compile test suite

# Modules
GROVE_BUILD_MODULES          # Compile hot-reloadable modules
GROVE_BUILD_BGFX_RENDERER    # Compile rendering module

# Debug
GROVE_ENABLE_TSAN            # ThreadSanitizer
GROVE_ENABLE_HELGRIND        # Helgrind deadlock detection
```

### Build Commands

```bash
# Configuration
cmake -B build -DGROVE_BUILD_IMPLEMENTATIONS=ON -DGROVE_BUILD_TESTS=ON

# Build
cmake --build build

# Tests
cd build && ctest

# Module seul (build autonome)
cd modules/BgfxRenderer && cmake . && make
```

### Platforms Supportées

| Platform | Status | Toolchain |
|----------|--------|-----------|
| **Windows** | ✅ Validé | MSVC, MinGW |
| **Linux** | ✅ Validé | GCC, Clang |
| **WSL2** | ✅ Validé | GCC |
| **macOS** | ⏳ Non testé | Clang |
| **WebAssembly** | 🔮 Futur | Emscripten |

---

## État Développement

### Validé (Production-Ready)

- ✅ **Hot-reload 0.4ms** avec state preservation
- ✅ **DebugEngine** avec logging complet
- ✅ **SequentialModuleSystem** (single-thread)
- ✅ **IntraIO** pub/sub avec TopicTree
- ✅ **JsonDataNode/JsonDataTree** configuration
- ✅ **Dynamic module loading** (dlopen/LoadLibrary)
- ✅ **Test suite** (Catch2)

### En Développement

- 🔄 **BgfxRenderer module**
  - ✅ Skeleton + RHI layer
  - ✅ Shaders pre-compiled
  - 🔄 SpritePass implementation
  - ⏳ TextPass, TilemapPass

### Planned

- ⏳ **ThreadedModuleSystem** (each module own thread)
- ⏳ **MultithreadedModuleSystem** (thread pool)
- ⏳ **LocalIO** (named pipes/sockets)
- ⏳ **NetworkIO** (TCP/WebSocket)
- ⏳ **Entity Component System** (YAML-driven)
- ⏳ **UI System** (JSON layouts)

---

## Projets Utilisateurs

| Projet | Type | Status |
|--------|------|--------|
| **AISSIA** | AI Assistant | En développement |
| **Pokrovsk: Iron Line** | Survival/Management | Concept |
| **WarFactory** | Source originale | Extraction faite |

---

## Problèmes Techniques Connus

### 1. API Mismatch IDataTree

**Situation** : Certaines implémentations utilisent l'ancienne API `nlohmann::json` au lieu de `IDataNode`.

```cpp
// Ancien (certains fichiers)
void initialize(const nlohmann::json& config, IIO* io);

// Nouveau (interface actuelle)
void initialize(const IDataNode& config, IIO* io);
```

**Status** : Migration en cours, wrapper temporaire disponible.

### 2. Cross-Platform Hot-Reload

| Platform | API | Status |
|----------|-----|--------|
| Windows | LoadLibrary/FreeLibrary | ✅ Validé |
| Linux | dlopen/dlclose | ✅ Validé |
| macOS | dlopen/dlclose | ⏳ Non testé |
| WASM | N/A | ⚠️ Architecture différente requise |

### 3. State Preservation Limits

- **Pointeurs** : Invalides après reload → Utiliser ID-based references
- **Handles externes** : (GPU textures, file handles) → Recréer après reload

---

## Commits Git Importants

| Commit | Date | Description |
|--------|------|-------------|
| **fc28009** | 24 Sept 2025 | Hot-reload 0.4ms validé, DebugEngine fonctionnel |
| **fb49fb2** | Sept 2025 | IntraIO implementation |
| **f6c3b34** | 27 Sept 2025 | IDataTree ajouté (breaking change) |
| **27 Oct 2025** | - | Extraction GroveEngine depuis WarFactory |

---

## Ressources

### Documentation Interne

- `GroveEngine/docs/architecture/` : Guides architecture
- `GroveEngine/docs/implementation/` : Guides implémentation
- `GroveEngine/README.md` : Quick start

### Références Externes

- **bgfx** : https://github.com/bkaradzic/bgfx
- **bgfx docs** : https://bkaradzic.github.io/bgfx/
- **SDL2** : https://wiki.libsdl.org/
- **nlohmann/json** : https://github.com/nlohmann/json

---

## Liens Projets Associés

- **AISSIA** : `Projects/WIP/AISSIA.md`
- **Pokrovsk** : `Projects/CONCEPT/pokrovsk_iron_line_v2.md`

---

*Créé : 27 octobre 2025*
*Consolidé : 27 novembre 2025*
*Stack : C++17, CMake, bgfx, nlohmann_json, spdlog*
*Performance : Hot-reload 0.4ms validé*