# Building Descent 3 Open Source
## Dependencies
The build process uses [**CMake**](https://cmake.org/) and, by default, [**Ninja**](https://ninja-build.org/). You must install these; the project cannot locate them for you. The source code depends on [**SDL2**](https://github.com/libsdl-org/SDL/tree/SDL2) and [**zlib**](https://github.com/madler/zlib). You can supply these dependencies yourself via your system's library management tools, or the build system can locate the dependencies for you using [vcpkg](https://github.com/microsoft/vcpkg), a cross-platform dependency-management system developed by Microsoft. The official builds source their dependencies from vcpkg.
## Installing and using vcpkg
* When building for Windows, vcpkg is already installed and configured when using any of the Visual Studio command prompts (either actual Command Prompt, or PowerShell).
* For Android, Linux or Mac (or non-standard-Windows) configurations, you will need to install vcpkg locally by cloning https://github.com/microsoft/vcpkg and setting your `VCPKG_ROOT` env var to the repository location. With this environment variable set, the build will automatically locate its dependencies.
## Building - Windows
1. **Install the prerequisite build tools.**
Make sure that you have Git and Visual Studio 2022 with the “Desktop development with C++” workload and the “C++ MFC for latest v143 build tools (x86 & x64)” component. If you don’t already have those installed or you aren’t sure, then open an elevated Command Prompt and run:
```batch
winget install Git.Git Microsoft.VisualStudio.2022.Community
"%ProgramFiles(x86)%\Microsoft Visual Studio\Installer\setup.exe" modify^
--passive^
--channelId VisualStudio.17.Release^
--productId Microsoft.VisualStudio.Product.Community^
--add Microsoft.VisualStudio.Workload.NativeDesktop;includeRecommended^
--add Microsoft.VisualStudio.Component.VC.ATLMFC
```
**NOTE:**
Builds _must_ be performed in one of the Visual Studio-provided **x64 Native Tools** command prompts ("x64 Native Tools Command Prompt" or "x64 Native Tools PowerShell"), _not_ a standard Command Prompt or PowerShell. The VS prompts will already have vcpkg installed and configured for use, so no dependency management is needed.
2. **Clone the Descent3 source code.**
Open a "x64 Native Tools Command Prompt" or "x64 Native Tools PowerShell" and run:
```batch
git clone https://github.com/DescentDevelopers/Descent3
```
4. **Build Descent3.**
```batch
cd Descent3
cmake --preset win
cmake --build --preset win --config [Debug|Release]
```
See [Build Options](#build-options) below for more information on `Debug` vs `Release`.
Once CMake finishes, the built files will be put in `builds\win\Descent3\Debug` or `builds\win\Descent3\Release`.
## Building - macOS
1. **Install the prerequisite build tools.**
* Make sure that [Xcode](https://developer.apple.com/xcode) is installed.
* Make sure that [Homebrew](https://brew.sh) is installed.
2. **Acquire the library dependencies.**
* If you would like to use vcpkg:
```sh
git clone https://github.com/microsoft/vcpkg
export VCPKG_ROOT="$PWD/vcpkg"
```
**NOTE:**
You will need `$VCPKG_ROOT` defined in the environment for all build runs. It is a good idea to set this in your `.bashrc` or equivalent.
* If you would like to manage the code dependencies yourself:
```sh
brew install sdl2 zlib googletest
```
3. **Clone the Descent3 source code.**
```sh
git clone https://github.com/DescentDevelopers/Descent3
```
4. **Build Descent3.**
```sh
cd Descent3
brew bundle install
cmake --preset mac
cmake --build --preset mac --config [Debug|Release]
```
See [Build Options](#build-options) below for more information on `Debug` vs `Release`.
Once CMake finishes, the built files will be put in `builds/mac/Descent3/Debug` or `builds/mac/Descent3/Release`.
## Building - Linux
1. **Install the prerequisite build tools.**
* APT users (Debian, Ubuntu)
```sh
sudo apt update
sudo apt install -y --no-install-recommends git ninja-build cmake g++
```
* DNF users (Red Hat, Fedora)
```sh
sudo dnf update --refresh
sudo dnf install -y git ninja-build cmake gcc-c++
```
2. **Acquire the library dependencies.**
* If you would like to use vcpkg:
1. Clone vcpkg:
```sh
git clone https://github.com/microsoft/vcpkg
export VCPKG_ROOT="$PWD/vcpkg"
```
**NOTE:**
You will need `$VCPKG_ROOT` defined in the environment for all build runs. It is a good idea to set this in your `.bashrc` or equivalent.
2. Install vcpkg-needed build tools and dependencies:
* APT users
```sh
sudo apt install -y --no-install-recommends curl pkg-config autoconf automake libtool libltdl-dev make python3-jinja2 libx11-dev libxft-dev libxext-dev libwayland-dev libxkbcommon-dev libegl1-mesa-dev libibus-1.0-dev libasound2-dev libpulse-dev libaudio-dev libjack-dev libsndio-dev
```
* DNF users
```sh
sudo dnf install -y autoconf automake libtool perl-open perl-FindBin python-jinja2 libX11-devel libXft-devel libXext-devel wayland-devel libxkbcommon-devel mesa-libEGL-devel ibus-devel alsa-lib-devel pulseaudio-libs-devel
```
* If you would like to manage the code dependencies yourself:
* APT users
```sh
sudo apt install -y --no-install-recommends libsdl2-dev zlib1g-dev libgtest-dev libglm-dev
```
* DNF users
```sh
sudo dnf install -y SDL2-devel zlib-devel gtest glm-devel
```
3. **Clone the Descent3 source code.**
```sh
git clone https://github.com/DescentDevelopers/Descent3
```
4. **Build Descent3.**
```sh
cd Descent3
cmake --preset linux
cmake --build --preset linux --config [Debug|Release]
```
See [Build Options](#build-options) below for more information on `Debug` vs `Release`.
Once CMake finishes, the built files will be put in `builds/linux/Descent3/Debug` or `builds/linux/Descent3/Release`.
## Build Options
The Descent3 build can be customized by [setting CMake variables on the command line](https://cmake.org/cmake/help/latest/manual/cmake.1.html#cmdoption-cmake-D) during its "Configuration" phase (the command without the `--build` option). To set a variable, you prepend the variable name with `-D` and then append the value, all as one single parameter. For example:
```sh
cmake --preset linux -DENABLE_LOGGER=ON
```
**NOTE:** CMake variables, or more technically _CMake cache entries_, will persist in their values until they are explicitly cleared. So, if you set a variable and then run another CMake command _without_ that variable specified, the variable will still be set. Variables must be explicitly unset, or the `builds/` directory cleaned, in order to be cleared.
| Option | Description | Default |
| ------ | ----------- | ------- |
| `CMAKE_BUILD_TYPE`
(or just [`--config`](https://cmake.org/cmake/help/latest/manual/cmake.1.html#cmdoption-cmake-build-config), without the `-D` syntax) |
`Debug` builds are generally larger, slower and contain extra correctness checks that will validate game data and interrupt gameplay when problems are detected.
`Release` builds are optimized for size and speed and do not include debugging information, which makes it harder to find problems.
| `Debug` | | `BUILD_EDITOR` | _(Windows-only)_ Build internal editor. | `OFF` | | `BUILD_TESTING` | Enable testing. Requires GTest. | `OFF` | | `ENABLE_LOGGER` | Enable logging to the terminal. | `OFF` | | `ENABLE_MEM_RTL` | Enable Real-time library memory management functions (disable to verbose memory allocations). | `ON` | | `FORCE_COLORED_OUTPUT` | Always produce ANSI-colored compiler warnings/errors (GCC/Clang only; esp. useful with Ninja). | `OFF` | | `FORCE_PORTABLE_INSTALL` | Install all files into local directory defined by `CMAKE_INSTALL_PREFIX`. | `ON` | | `USE_VCPKG` | Explicitly control whether or not to use vcpkg for dependency resolution. `ON` requires the environment variable `VCPKG_ROOT` to be set. | Determined by the existence of `VCPKG_ROOT` in the environment: If it exists, vcpkg is used. |