🎮 Lite2D — Simple, Beginner-Friendly C++ 2D Game Engine

Lite2D is a compact, easy-to-understand 2D game engine written in modern C++ (C++17) using SDL2.
Designed for learning and quick prototyping: no advanced IT skills required.

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⚡ Quick Start (Linux / macOS / Windows)

1. Open a terminal (or PowerShell on Windows).
2. From the project folder:

   mkdir -p build && cd build
   cmake .. -DCMAKE_BUILD_TYPE=Release
   cmake --build . --config Release

3. Run the executable:
   • Linux / macOS:

     ./lite2d

   • Windows (PowerShell):

     .\Release\lite2d.exe

If you prefer a single copy-paste on Linux:

git clone <repo> && cd Lite2D && mkdir build && cd build && cmake .. && cmake --build . && ./lite2d

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🧰 Prerequisites

• C++ compiler supporting C++17 (GCC, Clang, MSVC)
• CMake >= 3.10
• SDL2 development libraries

Quick install examples:

• Ubuntu / Debian:

  sudo apt update
  sudo apt install build-essential cmake libsdl2-dev

• Fedora:

  sudo dnf install gcc-c++ cmake SDL2-devel

• macOS (Homebrew):

  brew install cmake sdl2

• Windows:
  • Use vcpkg: vcpkg install sdl2 and pass -DCMAKE_TOOLCHAIN_FILE=.../vcpkg.cmake to CMake.

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✨ Highlights & Features

• Minimal ECS-ish design (Entity + Components)
• Delta-time movement for smooth, frame-rate independent motion
• Simple rendering of colored rectangles using SDL2
• Basic collision detection and bounce response
• Easy configuration: background color and FPS via Engine API
• Beginner-friendly sample entities (Player, Enemy, Obstacle)

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🧭 Controls & Behavior

• Close window or press ESC to exit.
• Sample entities demonstrate movement, wrapping at screen edges, and collisions.

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🛠 Troubleshooting (common, simple fixes)

• CMake reports "SDL2 not found":
  • Ensure libsdl2-dev (Linux) or sdl2 (Homebrew) is installed.
  • On Windows ensure CMake can find SDL2 or use vcpkg toolchain.
• Runtime: missing SDL2 shared library (.so/.dll):
  • Linux: install SDL2 runtime or set LD_LIBRARY_PATH to the SDL2 location.
  • Windows: place SDL2.dll next to the executable or add its folder to PATH.
• Build errors about C++ standard:
  • Ensure your compiler supports C++17. Add -std=c++17 if needed.

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🗂 Project Structure (what to look at)

• src/main.cpp — app entry and simple config
• src/Engine.h / src/Engine.cpp — main loop, input, update, render
• src/Entity.h — entity container
• src/Components.h — transform, render, velocity, collider, tag
• CMakeLists.txt — build configuration

To add or customize content (very simple):

• Edit Engine::CreateEntities() to add new squares, colors, velocities.
• Change background or FPS in main.cpp using engine.SetBackgroundColor(...) and engine.SetFPS(...).

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🛠 How to Use It (easy steps for everyone)

This short guide shows the simplest ways to run, play with, and lightly customize Lite2D — no deep IT skills required.

1. Run the app (already built)

   • From the project folder:
   • Or double-click the lite2d executable in your file manager (Linux) after building.

2. Play

   • The window shows simple colored squares.
   • Close the window or press ESC to quit.

3. Change the background color or FPS (no strong programming needed)

   • Open src/main.cpp in a text editor (VS Code, Notepad++, gedit).
   • Find these lines and change the numbers:

     engine.SetBackgroundColor(20, 20, 40); // r, g, b (0-255)
     engine.SetFPS(60);                     // frames per second

   • Save and rebuild:

     cd build
     cmake ..
     cmake --build .
     ./lite2d

4. Add or edit a square (super simple)

   • Open src/Engine.cpp and find Engine::CreateEntities().
   • Copy one of the example entities and tweak values:

     auto myBox = std::make_unique<Entity>();
     myBox->transform = std::make_unique<TransformComponent>(100.0f, 120.0f, 40, 40); // x, y, width, height
     myBox->render = std::make_unique<RenderComponent>(255, 200, 0); // r, g, b (0-255)
     myBox->velocity = std::make_unique<VelocityComponent>(0.0f, 0.0f); // vx, vy (pixels/sec)
     myBox->tag = std::make_unique<TagComponent>("MyBox");
     entities.push_back(std::move(myBox));

   • Save, rebuild, and run to see the new square.

5. Tweak movement without advanced code

   • velocity vx (positive = right, negative = left), vy (positive = down, negative = up).
   • Larger absolute numbers = faster movement.

6. Remove an object without deleting code

   • Set visibility to false:

     entity->render->visible = false;

   • Or mark for deletion at runtime:

     entity->Destroy();

7. If something goes wrong

   • Copy any terminal error and ask for help (paste the text).
   • For SDL2 missing errors, follow the Prerequisites section to install SDL2.

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🤝 Contributing & Support

Contributions and questions are welcome. Suggested workflow:

• Open an issue to discuss larger changes
• Submit small, focused pull requests
• Add comments for new logic and simple examples/demos

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📄 License

MIT — see LICENSE file.