vcmi/docs/developers/Building_Linux.md

# Compiling VCMI

- Current baseline requirement for building is Ubuntu 20.04
- Supported C++ compilers for UNIX-like systems are GCC 9+ and Clang 13+

Older distributions and compilers might work, but they aren't tested by Github CI (Actions)

# Installing dependencies

## Prerequisites

To compile, the following packages (and their development counterparts) are needed to build:

-   CMake
-   SDL2 with devel packages: mixer, image, ttf
-   zlib and zlib-devel
-   Boost C++ libraries v1.48+: program-options, filesystem, system, thread, locale
-   Recommended, if you want to build launcher or map editor: Qt 5, widget and network modules
-   Recommended, FFmpeg libraries, if you want to watch in-game videos: libavformat and libswscale. Their name could be libavformat-devel and libswscale-devel, or ffmpeg-libs-devel or similar names. 
-   Optional:
    - if you want to build scripting modules: LuaJIT
    - to speed up recompilation: Ccache

## On Debian-based systems (e.g. Ubuntu)

For Ubuntu and Debian you need to install this list of packages:

`sudo apt-get install cmake g++ clang libsdl2-dev libsdl2-image-dev libsdl2-ttf-dev libsdl2-mixer-dev zlib1g-dev libavformat-dev libswscale-dev libboost-dev libboost-filesystem-dev libboost-system-dev libboost-thread-dev libboost-program-options-dev libboost-locale-dev libboost-iostreams-dev qtbase5-dev libtbb-dev libluajit-5.1-dev liblzma-dev libsqlite3-dev qttools5-dev ninja-build ccache`

Alternatively if you have VCMI installed from repository or PPA you can use:

`sudo apt-get build-dep vcmi`

## On RPM-based distributions (e.g. Fedora)

`sudo yum install cmake gcc-c++ SDL2-devel SDL2_image-devel SDL2_ttf-devel SDL2_mixer-devel boost boost-devel boost-filesystem boost-system boost-thread boost-program-options boost-locale boost-iostreams zlib-devel ffmpeg-devel ffmpeg-libs qt5-qtbase-devel tbb-devel luajit-devel liblzma-devel libsqlite3-devel fuzzylite-devel ccache`

NOTE: `fuzzylite-devel` package is no longer available in recent version of Fedora, for example Fedora 38. It's not a blocker because VCMI bundles fuzzylite lib in its source code.

## On Arch-based distributions

On Arch-based distributions, there is a development package available for VCMI on the AUR.

It can be found at: <https://aur.archlinux.org/packages/vcmi-git/>

Information about building packages from the Arch User Repository (AUR) can be found at the Arch wiki.

# Getting the sources

We recommend the following directory structure:

    .
    ├── vcmi -> contains sources and is under git control
    └── build -> contains build output, makefiles, object files,...

Out-of-source builds keep the local repository clean so one doesn't have to manually exclude files generated during the build from commits.

You can get latest sources with:

`git clone -b develop --recursive https://github.com/vcmi/vcmi.git`

# Compilation

## Configuring Makefiles

```sh
mkdir build && cd build
cmake -S ../vcmi
```

# Additional options that you may want to use:

## To enable debugging:
`cmake -S ../vcmi -D CMAKE_BUILD_TYPE=Debug`

**Notice**: The ../vcmi/ is not a typo, it will place makefile scripts into the build dir as the build dir is your working dir when calling CMake.

## To use ccache:
`cmake -S ../vcmi -D ENABLE_CCACHE:BOOL=ON`

## Trigger build

`cmake --build . -- -j2`
(-j2 = compile with 2 threads, you can specify any value)

That will generate vcmiclient, vcmiserver, vcmilauncher as well as .so libraries in the **build/bin/** directory.

# Package building

## RPM package

The first step is to prepare a RPM build environment. On Fedora systems you can follow this guide: http://fedoraproject.org/wiki/How_to_create_an_RPM_package#SPEC_file_overview

0. Enable RPMFusion free repo to access to ffmpeg libs:

```sh
sudo dnf install https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm
```

NOTE: the stock ffmpeg from Fedora repo is no good as it has stripped lots of codecs

1. Perform a git clone from a tagged branch for the right Fedora version from https://github.com/rpmfusion/vcmi; for example for Fedora 38: <pre>git clone -b f38 --single-branch https://github.com/rpmfusion/vcmi.git</pre>

2. Copy all files to ~/rpmbuild/SPECS with command: <pre>cp vcmi/*  ~/rpmbuild/SPECS</pre>

3. Fetch all sources by using spectool:

```sh
sudo dnf install rpmdevtools
spectool -g -R ~/rpmbuild/SPECS/vcmi.spec
```

4. Fetch all dependencies required to build the RPM:

```sh
sudo dnf install dnf-plugins-core
sudo dnf builddep ~/rpmbuild/SPECS/vcmi.spec
```

4. Go to ~/rpmbuild/SPECS and open terminal in this folder and type: 
```sh
rpmbuild -ba ~/rpmbuild/SPECS/vcmi.spec
```

5. Generated RPM is in folder ~/rpmbuild/RPMS

If you want to package the generated RPM above for different processor architectures and operating systems you can use the tool mock.
Moreover, it is necessary to install mock-rpmfusion_free due to the packages ffmpeg-devel and ffmpeg-libs which aren't available in the standard RPM repositories(at least for Fedora). Go to ~/rpmbuild/SRPMS in terminal and type: 

```sh
mock -r fedora-38-aarch64-rpmfusion_free path_to_source_RPM
mock -r fedora-38-x86_64-rpmfusion_free path_to_source_RPM
```

For other distributions that uses RPM, chances are there might be a spec file for VCMI. If there isn't, you can adapt the RPMFusion's file

Available root environments and their names are listed in /etc/mock.

## Debian/Ubuntu

1. Install debhelper and devscripts packages

2. Run dpkg-buildpackage command from vcmi source directory

```sh
sudo apt-get install debhelper devscripts
cd /path/to/source
dpkg-buildpackage
```

To generate packages for different architectures see "-a" flag of dpkg-buildpackage command