Doc: split compiling instructions from README, as they aren't required for casual GitHub visitors

1 files changed, 141 insertions, 0 deletions

diff --git a/COMPILING.md b/COMPILING.md
new file mode 100644
index 000000000..46de5e09e
--- /dev/null
+++ b/COMPILING.md
@@ -0,0 +1,141 @@
+# Compiling OpenTTD
+
+## Required/optional libraries
+
+The following libraries are used by OpenTTD for:
+
+- zlib: (de)compressing of old (0.3.0-1.0.5) savegames, content downloads,
+   heightmaps
+- liblzo2: (de)compressing of old (pre 0.3.0) savegames
+- liblzma: (de)compressing of savegames (1.1.0 and later)
+- libpng: making screenshots and loading heightmaps
+- libfreetype: loading generic fonts and rendering them
+- libfontconfig: searching for fonts, resolving font names to actual fonts
+- libicu: handling of right-to-left scripts (e.g. Arabic and Persian) and
+   natural sorting of strings (Linux only)
+- libSDL2: hardware access (video, sound, mouse) (not required for Windows or macOS)
+
+OpenTTD does not require any of the libraries to be present, but without
+liblzma you cannot open most recent savegames and without zlib you cannot
+open most older savegames or use the content downloading system.
+Without libSDL/liballegro on non-Windows and non-macOS machines you have
+no graphical user interface; you would be building a dedicated server.
+
+## Windows:
+
+You need Microsoft Visual Studio 2015 Update 3 or newer.
+
+You can download the free Visual Studio Community Edition from Microsoft at
+https://visualstudio.microsoft.com/vs/community/.
+
+OpenTTD needs the Platform SDK, if it isn't installed already. This can be
+done during installing Visual Studio, by selecting
+`Visual C++ MFC for x86 and x64` (and possibly
+`Visual C++ ATL for x86 and x64` depending on your version). If not, you
+can get download it as [MS Windows Platform SDK](https://developer.microsoft.com/en-US/windows/downloads/windows-10-sdk).
+
+Install the SDK by following the instructions as given.
+
+Dependencies for OpenTTD on Windows are handled via
+[vcpkg](https://github.com/Microsoft/vcpkg/). First you need to install vcpkg
+by following the `Quick Start` instructions of their
+[README](https://github.com/Microsoft/vcpkg/blob/master/README.md).
+
+After this, you can install the dependencies OpenTTD needs. We advise to use
+the `static` versions, and OpenTTD currently needs the following dependencies:
+
+- liblzma
+- libpng
+- lzo
+- zlib
+
+To install both the x64 (64bit) and x86 (32bit) variants (though only one is necessary), you can use:
+
+```ps
+.\vcpkg install liblzma:x64-windows-static libpng:x64-windows-static lzo:x64-windows-static zlib:x64-windows-static
+.\vcpkg install liblzma:x86-windows-static libpng:x86-windows-static lzo:x86-windows-static zlib:x86-windows-static
+```
+
+Open the relevant project file and it should build automatically.
+- VS 2015: projects/openttd_vs140.sln
+- VS 2017: projects/openttd_vs141.sln
+- VS 2019: projects/openttd_vs142.sln
+
+Set the build mode to `Release` in
+`Build > Configuration manager > Active solution configuration`.
+You can now compile.
+
+If everything works well the binary should be in `objs\Win[32|64]\Release\openttd.exe`
+and in `bin\openttd.exe`
+
+The OpenTTD wiki may provide additional help with [compiling for Windows](https://wiki.openttd.org/Compiling_on_Windows_using_Microsoft_Visual_C%2B%2B_2015).
+
+You can also build OpenTTD with MSYS2/MinGW-w64 or Cygwin/MinGW using the Makefile.  The OpenTTD wiki may provide additional help with [MSYS2](https://wiki.openttd.org/Compiling_on_Windows_using_MSYS2)
+
+## Linux, Unix, Solaris:
+
+OpenTTD can be built with GNU '`make`'. On non-GNU systems it is called '`gmake`'.
+However, for the first build one has to do a '`./configure`' first.
+
+The OpenTTD wiki may provide additional help with:
+
+- [compiling for Linux and *BSD](https://wiki.openttd.org/Compiling_on_%28GNU/%29Linux_and_*BSD)
+- [compiling for Solaris](https://wiki.openttd.org/Compiling_on_Solaris)
+
+
+## macOS:
+
+Use '`make`' or Xcode (which will then call make for you)
+This will give you a binary for your CPU type (PPC/Intel)
+However, for the first build one has to do a '`./configure`' first.
+To make a universal binary type '`./configure --enable-universal`'
+instead of '`./configure`'.
+
+The OpenTTD wiki may provide additional help with [compiling for macOS](https://wiki.openttd.org/Compiling_on_Mac_OS_X).
+
+## Haiku:
+
+Use '`make`', but do a '`./configure`' before the first build.
+
+The OpenTTD wiki may provide additional help with [compiling for Haiku](https://wiki.openttd.org/Compiling_on_Haiku).
+
+## OS/2:
+
+A comprehensive GNU build environment is required to build the OS/2 version.
+
+The OpenTTD wiki may provide additional help with [compiling for OS/2](https://wiki.openttd.org/Compiling_on_OS/2).
+
+## Supported compilers
+
+The following compilers are tested with and known to compile OpenTTD:
+
+- Microsoft Visual C++ (MSVC) 2015, 2017 and 2019.
+- GNU Compiler Collection (GCC) 4.8 - 9.
+- Clang/LLVM 3.9 - 8
+
+The following compilers are known not to compile OpenTTD:
+
+In general, this is because these old versions do not (fully) support modern
+C++11 language features.
+
+- Microsoft Visual C++ (MSVC) 2013 and earlier.
+- GNU Compiler Collection (GCC) 4.7 and earlier.
+- Clang/LLVM 3.8 and earlier.
+
+If any of these, or any other, compilers can compile OpenTTD, let us know.
+Pull requests to support more compilers are welcome.
+
+## Compilation of base sets
+
+To recompile the extra graphics needed to play with the original Transport
+Tycoon Deluxe graphics you need GRFCodec (which includes NFORenum) as well.
+GRFCodec can be found at https://www.openttd.org/download-grfcodec.
+The compilation of these extra graphics does generally not happen, unless
+you remove the graphics file using '`make maintainer-clean`'.
+
+Re-compilation of the base sets, thus also use of '`--maintainer-clean`' can
+leave the repository in a modified state as different grfcodec versions can
+cause binary differences in the resulting grf. Also translations might have
+been added for the base sets which are not yet included in the base set
+information files. Use the configure option '`--without-grfcodec`' to avoid
+modification of the base set files by the build process.