Building CNA

CMake-based build system  ·  C++23 required

Step 1 — Clone and initialise submodules

git clone https://github.com/openeggbert/cna.git
cd cna
git submodule update --init --recursive

This populates third_party/SDL, third_party/SDL_image, and third_party/SDL_mixer. After this step, SDL is built from source by the CMake build — no system SDL packages are required.

Step 2 — Select a backend and build

CNA requires exactly one rendering backend to be selected at configuration time via -DCNA_GRAPHICS_BACKEND=<BACKEND>. Available backends: SDL_RENDERER, EASYGL, BGFX, VULKAN.

Linux — EasyGL (OpenGL) backend

cmake -S . -B build -DCNA_GRAPHICS_BACKEND=EASYGL
cmake --build build --target CNA CnaTests

Requires ../easy-gl to be present alongside the CNA repository.

Linux — SDL_Renderer backend

cmake -S . -B build-sdlrenderer -DCNA_GRAPHICS_BACKEND=SDL_RENDERER
cmake --build build-sdlrenderer --target CNA CnaTests

Windows — SDL_Renderer backend (MSVC)

On Windows with MSVC 2022 opened from a Developer Command Prompt:

git submodule update --init --recursive
cmake -S . -B build-win -DCNA_GRAPHICS_BACKEND=SDL_RENDERER
cmake --build build-win --target CNA CnaTests

Linux → Windows cross-compilation (MinGW-w64)

# Install the cross toolchain (Debian/Ubuntu)
sudo apt install mingw-w64

git submodule update --init --recursive
cmake -S . -B build-windows \
      -DCMAKE_TOOLCHAIN_FILE=cmake/toolchains/mingw-w64.cmake \
      -DCNA_GRAPHICS_BACKEND=SDL_RENDERER
cmake --build build-windows --target CNA CnaTests

bgfx backend

cmake -S . -B build-bgfx -DCNA_GRAPHICS_BACKEND=BGFX
cmake --build build-bgfx --target CNA

bgfx is fetched via CMake FetchContent — no separate clone needed. Implementation is ongoing; not all features are complete.

Vulkan backend (stub)

cmake -S . -B build-vulkan -DCNA_GRAPHICS_BACKEND=VULKAN
cmake --build build-vulkan --target CNA

The Vulkan backend is an architecture scaffold. Implementation is incomplete and contains stub areas.

Optional: use system-installed SDL

By default CNA builds SDL3 from the vendored submodules. If you prefer to link against system SDL3 packages, pass -DCNA_USE_SYSTEM_SDL=ON:

cmake -S . -B build -DCNA_USE_SYSTEM_SDL=ON -DCNA_GRAPHICS_BACKEND=SDL_RENDERER
cmake --build build --target CNA CnaTests

This calls find_package for SDL3, SDL3_image, and SDL3_mixer. The packages must be installed (e.g. via your distribution's package manager).

Running the tests

ctest --test-dir build --output-on-failure

Running the demos

# Hello-triangle verification target
cmake --build build --target hello-triangle-sdl

# 3D cube demo (if present)
cmake --build build --target cna_cube3d_demo
./build/cna_cube3d_demo

Tested compiler matrix

CMake options reference

Troubleshooting

sharp-runtime not found

CNA requires sharp-runtime to be present as a sibling directory:

parent/
├── cna/
└── sharp-runtime/

Clone sharp-runtime next to CNA and re-run CMake configuration.

easy-gl not found (EASYGL backend)

The EASYGL backend requires easy-gl as a sibling directory. Clone it alongside CNA or switch to SDL_RENDERER if you do not need OpenGL.

Submodule directories empty

Run git submodule update --init --recursive from the repository root. If this fails, check your network and that the submodule URLs in .gitmodules are accessible.