# CyrusEngine (Imperial Edition)

CyrusEngine is a work-in-progress C++ 2D game-engine foundation. It provides a GLFW/OpenGL application loop, sprite and shape rendering, FreeType-based text, EnTT entity components, and Box2D-backed physics.

The public engine declarations are in `src/CyrusEngine.h`. The current build uses C++23. APIs and project structure may change while the engine is under development.

## Features

- GLFW window and application lifecycle, timing, keyboard input, and projection helpers
- OpenGL sprite rendering, texture regions, and sprite-sheet animation
- Batched 2D shapes, including lines, circles, and rectangles
- FreeType font atlas generation and text rendering
- EnTT-based entity-component workflows
- Box2D physics integration with pixel/metre conversion helpers

## Requirements

The documented CMake build is currently intended for Linux. Other operating systems and graphics drivers have not been verified.

- CMake 3.20 or newer
- A C and C++ compiler with C++23 support
- OpenGL development files
- GLEW and GLFW 3 development files
- `pkg-config`
- For the playground target: libsndfile, Vorbisfile, and PortAudio development files

On Debian or Ubuntu, install the common prerequisites with:

```sh
sudo apt install build-essential cmake pkg-config libgl-dev libglew-dev libglfw3-dev \
  libsndfile1-dev libvorbis-dev portaudio19-dev
```

The repository vendors Box2D, EnTT, FreeType, GLM, microui, and stb_image under `src/3rdparty`; the CMake build uses these bundled sources/headers where applicable.

## Build With CMake

From the repository root:

```sh
cmake -S . -B build/cmake -DCMAKE_BUILD_TYPE=Debug
cmake --build build/cmake --parallel
```

This builds the `cyrusengine` static library and the `playground` executable. To build only the engine library, disable the playground (which avoids its audio development-package requirements):

```sh
cmake -S . -B build/cmake -DCYRUSENGINE_BUILD_PLAYGROUND=OFF
cmake --build build/cmake --parallel
```

The CMake target alias for consumers adding this project as a subdirectory is `CyrusEngine::CyrusEngine`.

### Run the Playground

The example refers to assets relative to its working directory. Run it from `examples/playground`:

```sh
cd examples/playground
../../build/cmake/playground
```

## Build With MakeIt

MakeIt is also supported through the existing `MakeIt.toml` configuration. With MakeIt installed, run the build command from the repository root:

```sh
makeit build -j8
```

## Minimal Application Loop

```cpp
#include "CyrusEngine.h"

int main()
{
    CE::EngineConfiguration config;
    config.windowTitle = "My CyrusEngine App";

    CE::Initialize(config);

    while (CE::Run())
    {
        CE::BeginRendering();
        CE::ClearBuffer();

        // Update and render your game here.

        CE::EndRendering();
    }

    CE::Shutdown();
    return 0;
}
```

## Licensing and Third-Party Software

Original CyrusEngine project code is offered under the Apache License 2.0; see [`LICENSE`](LICENSE). This license does not replace the licenses for bundled third-party code or assets.

Before publishing, confirm that you are authorized to license all original contributions under Apache-2.0. Existing source headers identify historical authors but do not, by themselves, establish the current copyright holder.

Third-party components are located under `src/3rdparty`. Preserve their copyright and license notices and review each component's terms before redistributing a source or binary release. Some components include separate license files (for example, FreeType and microui); other notices may be embedded in source files or in the upstream distribution.

The repository also contains example fonts, images, and sound files under `examples/assets`. Their redistribution permissions are not documented here. Confirm that you have the necessary rights and include any required attributions before publishing or distributing those assets; otherwise remove or replace them.