GroveEngine 🌳

Experimental Modular C++ Engine Architecture for Rapid Prototyping

GroveEngine is a lightweight, modular engine architecture designed for blazing-fast development iteration (0.4ms hot-reload validated) and optimized for AI-assisted prototyping. Currently in development stage - suitable for experimentation and learning, not production games.

Key Features

• 🔥 Hot-Reload 0.4ms - Validated blazing-fast module reloading
• 🧩 Modular Architecture - Clean separation via interfaces (IEngine, IModule, IIO, IModuleSystem)
• 🚀 Development Velocity - Edit → Build → Hot-reload < 1 second total
• 🤖 AI-Assisted Development - 200-300 line modules optimized for Claude Code
• 📦 Autonomous Builds - Each module builds independently
• ⚠️ Experimental - Non-deterministic, development-focused architecture

Architecture Overview

grove::IEngine (Orchestration)
├── grove::IModuleSystem (Execution strategy)
│   ├── SequentialModuleSystem (✅ Implemented - 1 module at a time)
│   ├── ThreadedModuleSystem (🚧 TODO - Each module in thread)
│   └── MultithreadedModuleSystem (🚧 TODO - Thread pool)
├── grove::IModule (Business logic - 200-300 lines)
│   └── Your modules (.so/.dll hot-reloadable)
└── grove::IIO (Communication)
    ├── IntraIO (✅ Implemented - Same process pub/sub)
    ├── LocalIO (🚧 TODO - Same machine IPC)
    └── NetworkIO (🚧 TODO - Distributed messaging)

Current Status

⚠️ Development Stage: GroveEngine is currently development-ready but not production-ready. The engine is non-deterministic and suited for prototyping, experimentation, and rapid iteration. Production use requires significant additional work (see Roadmap).

✅ Implemented Components

• Core Engine:

  • DebugEngine - Comprehensive logging and health monitoring
  • SequentialModuleSystem - Single-threaded module execution
  • IntraIO + IntraIOManager - Sub-millisecond pub/sub with pattern matching
  • ModuleLoader - Hot-reload system (0.4ms average, 0.055ms best)

• Rendering Stack (BgfxRenderer):

  • Sprite rendering with automatic batching
  • Tilemap rendering with instancing
  • Particle effects system
  • Debug text overlay (8x8 bitmap font)
  • RHI abstraction over bgfx

• UI System (UIModule):

  • 10 widget types (button, panel, label, checkbox, slider, text input, progress bar, image, scroll panel, tooltip)
  • JSON layout loading
  • Retained mode rendering (85%+ IIO reduction)
  • Thread-safe input handling

• Input System (InputModule):

  • Mouse (movement, buttons, wheel)
  • Keyboard (keys, text input)
  • SDL2 backend

• Test Suite: 20+ integration tests + visual demos

⚠️ Known Limitations

• Non-Deterministic Execution: Module execution order not guaranteed
• Single-Threaded Only: Only SequentialModuleSystem implemented
• No Determinism Guarantees: Not suitable for networked games or replays
• Development Focus: Optimized for rapid iteration, not stability

🚧 Roadmap to Production

• Deterministic Execution: Predictable module execution order
• Module Systems: ThreadedModuleSystem, MultithreadedModuleSystem
• IO Systems: LocalIO (IPC), NetworkIO (distributed)
• Input: Gamepad support (Phase 2)
• Renderer: Advanced text rendering, post-processing effects
• Stability: Error recovery, graceful degradation
• Performance: Profiling, optimization, memory pooling

Quick Start

Try the Interactive Demo

See it in action first! Run the full stack demo to see BgfxRenderer + UIModule + InputModule working together:

# Windows
run_full_stack_demo.bat

# Linux
./build/tests/test_full_stack_interactive

Features:

• Click buttons, drag sliders, interact with UI
• Spawn bouncing sprites with physics
• Complete input → UI → game → render flow
• All IIO topics demonstrated

See tests/visual/README_FULL_STACK.md for details.

Directory Structure

GroveEngine/
├── include/grove/          # 27 headers
│   ├── IEngine.h          # Core interfaces
│   ├── IModule.h
│   ├── IModuleSystem.h
│   ├── IIO.h
│   ├── IDataTree.h        # Configuration system
│   ├── IDataNode.h
│   └── ...
├── src/                    # 10 implementations
│   ├── DebugEngine.cpp
│   ├── SequentialModuleSystem.cpp
│   ├── IntraIO.cpp
│   ├── ModuleFactory.cpp
│   └── ...
├── docs/                   # Documentation
│   ├── architecture/
│   │   ├── architecture-modulaire.md
│   │   └── claude-code-integration.md
│   └── implementation/
│       └── CLAUDE-HOT-RELOAD-GUIDE.md
├── modules/                # Your application modules
├── tests/                  # Tests
└── CMakeLists.txt         # Build system

Build

cd GroveEngine
mkdir build && cd build
cmake ..
make

# Or use the root CMakeLists.txt directly
cmake .
make

Create a Module

// MyModule.h
#include <grove/IModule.h>

class MyModule : public grove::IModule {
public:
    json process(const json& input) override {
        // Your logic here (200-300 lines max)
        return {"result": "processed"};
    }

    void setConfiguration(const IDataNode& config, IIO* io, ITaskScheduler* scheduler) override {
        // Configuration setup
    }

    // ... other interface methods
};

Documentation

For Developers Using GroveEngine

• DEVELOPER_GUIDE.md - 📘 START HERE - Complete guide with modules, IIO topics, and full examples
• USER_GUIDE.md - Module system basics, hot-reload, IIO communication

Module Documentation

• BgfxRenderer - 2D rendering (sprites, tilemap, particles, debug text)
• UIModule - User interface (10 widget types, layout, scrolling)
• InputModule - Input handling (mouse, keyboard via SDL)

Architecture & Internals

• Architecture Modulaire - Core interface architecture
• Claude Code Integration - AI-optimized development workflow
• Hot-Reload Guide - 0.4ms hot-reload system

Philosophy

Micro-Context Development

• Small modules (200-300 lines) for AI-friendly development
• Autonomous builds - Zero parent dependencies
• Hot-swappable infrastructure - Change performance without touching business logic

Progressive Evolution

// Current (Production-Ready)
DebugEngine + SequentialModuleSystem + IntraIO

// Future Vision (Roadmap)
HighPerfEngine + MultithreadedModuleSystem + NetworkIO
// Same module code - just swap the infrastructure

Complexity Through Simplicity

Complex behavior emerges from the interaction of simple, well-defined modules.

Performance

Hot-Reload Benchmarks (Validated):

• Average: 0.4ms
• Best: 0.055ms
• 5-cycle test: 2ms total
• State persistence: 100% success rate
• Classification: 🚀 BLAZING (Theoretical maximum achieved)

Origin & Development

• WarFactory - Original architecture source and inspiration
• AISSIA - Experimental AI assistant project (development/testing)

GroveEngine is currently used for prototyping and experimentation, not production deployments.

License

GroveEngine is dual-licensed - you choose the license that fits your project:

📜 GPL v3 (Open Source - Free)

Use GroveEngine in open-source projects under the GNU GPL v3.

• ✅ 100% Free - No costs, no royalties
• ✅ Full engine access - Modify and use freely
• ❗ Your game must be GPL - Source code must be published
• 👥 Community support

💼 Commercial License (Proprietary - Royalty-Based)

Use GroveEngine in closed-source commercial games under the Commercial License.

• ✅ FREE up to €100,000 revenue per project
• ✅ 1% royalty on revenue above €100,000
• ✅ Keep your code private - Proprietary games allowed
• ✅ Email support - 72h response time
• ✅ Priority bug fixes

🎮 Best for indie developers: Most favorable royalty model in the industry!

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📊 License Comparison

Feature	GPL v3 (Free)	Commercial
Cost	Free	Free up to €100k revenue
Royalties	None	1% above €100k
Your game license	Must be GPL (open)	Proprietary allowed
Engine modifications	Share modifications	Keep private
Support	Community	Email (72h) + priority
Updates	Yes	Yes + priority fixes
Attribution	Required	Required ("Powered by")
Number of projects	Unlimited	Unlimited

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❓ FAQ - Which License Should I Choose?

Q: I'm making a commercial indie game. Which license? A: Commercial License - It's FREE until €100k, then only 1% royalties. Much better than Unreal (5% above $1M).

Q: I'm making an open-source game. Which license? A: GPL v3 - Perfect for open-source projects, 100% free forever.

Q: How do I declare my revenue? A: Annual email with your project revenue. Simple and trust-based. Audits possible but rare.

Q: Can I modify the engine? A: Yes! Both licenses allow modifications. GPL requires sharing them, Commercial lets you keep them private.

Q: Is GroveEngine cheaper than Unreal Engine? A: Yes! We charge 1% above €100k vs Unreal's 5% above $1M USD. For a €500k game, you'd pay €4,000 with GroveEngine vs €0 with Unreal (under threshold). For a €1.5M game: €14,000 vs ~€25,000 with Unreal.

Q: What if my game makes €80,000? A: €0 royalties! You're within the free tier. No payment required.

Q: Is support included? A: GPL = community support. Commercial = email support (72h response) + priority bug fixes.

Q: How do I get the Commercial License? A: Email alexistrouve.pro@gmail.com with subject "GroveEngine Commercial License Request". No upfront payment - royalties only after €100k!

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🏆 Industry Comparison

Engine	Free Tier	Royalty	Notes
GroveEngine	€0 - €100k	1% > €100k	Best for EU indie devs
Unreal Engine	$0 - $1M USD	5% > $1M	Higher %, higher threshold
Unity	Subscription	None	Monthly fees (~€2k/year Pro)
Godot	100% Free	None	MIT, but minimal official support

GroveEngine = Best value for games earning €100k - €500k 🎯

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📧 License Questions? Contact alexistrouve.pro@gmail.com

Contributing

This engine uses an architecture optimized for Claude Code development. Each module is autonomous and can be developed independently.

Constraints:

• ✅ Modules 200-300 lines maximum
• ✅ Autonomous build: cmake . from module directory
• ✅ JSON-only communication between modules
• ✅ Zero dependencies up (no #include "../")
• ❌ Never cmake ..

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GroveEngine - Where modules grow like trees in a grove 🌳