This is a guide to get you started on coding for The Powder Toy. Before doing anything, make sure you are checked out to the latest commit on the master branch, which this guide is kept up to date with. If you have any questions, just ask in the Development Assistance section on The Powder Toy forums or in the #development channel of our discord server.

Compiling for Windows

With MSVC

Tested on Windows 10.

MSVC is Microsoft's C/C++ compiler for Windows, which comes with Visual Studio. Using MSVC is the recommended way to build TPT on Windows if you are new to modding or have any reason whatsoever to prefer MSVC over MinGW (for which a separate guide is provided below).

Required environment setup

• install Git (get it here)
  • options should be left unchanged
• install Python (get it here)
  • it is recommended to allow the installer to add Python to PATH and to disable the path length limit (the latter is offered near the end of the installation process)
• open an elevated command prompt (search for "cmd" in the Start Menu, right-click the most sensible result, click "Run as administrator") and execute the following commands (you can close the prompt afterwards)

python -m pip install --upgrade pip
python -m pip install --upgrade meson ninja

• open a non-elevated command prompt (the same as before, but instead of running as administrator, just run it by clicking its shortcut) and execute the following commands (you can close the prompt afterwards)
  • replace [wherever you keep your repositories] with the actual path, taking care to remove the [] characters also; if the path has spaces in it, add "" around it
    • example: if your repositories are in C:\Users\Powder Toy Fan\Development, this path will be "C:\Users\Powder Toy Fan\Development"

cd /d [wherever you keep your repositories]
git clone https://github.com/The-Powder-Toy/The-Powder-Toy

Building for the first time

• install Visual Studio (get it here; no, Visual Studio Code is not the same as Visual Studio, you need Visual Studio)
  • make sure you install at least the "Desktop development with C++" workload
• open a (non-elevated) command prompt and execute the following commands

cd /d [wherever you keep your repositories]
cd The-Powder-Toy
meson setup build-debug
cd build-debug
meson compile

• make sure Meson is using MSVC (look for cl in the log the setup step prints)
• you may see a few warnings throughout all of this, but no errors (if you do at any stage, do not try to skip it; ask us about it on the forum instead)
  • if you are not sure, run meson compile again; if it says "no work to do", everything worked fine
• at this point, running TPT from the prompt should be possible

powder.exe

Using the Visual Studio IDE

The method above does not let you use the 'Visual' part of Visual Studio, the IDE. Although Meson has limited support for this use case, if you know how to use the IDE and for some reason you wish to use it, you can ask Meson to generate a build site that uses Visual Studio instead of Ninja.

• open a command prompt (see above) and execute the following commands

cd /d [wherever you keep your repositories]
cd The-Powder-Toy
meson setup --backend=vs -Dbackend_startup_project=powder build-debug-vs

• you will not need the command prompt beyond this point

This will generate a build site with a Visual Studio solution inside (the-powder-toy.sln). You can use this as any other solution, except for a few key differences:

• the IDE can only be used for more comfortable editing and debugging and not much else, definitely not things such as changing the project structure or compiler flags; you will have to familiarise yourself with Meson and work with the meson.build files in order to do that
• once you actually change meson.build files, Meson will automatically regenerate the solution the next time you try to build it; Visual Studio will give you a scary popup about the solution having been changed, which is perfectly normal, just click 'Reload Solution'
• the configuration you currently see (most likely debug|x64, if you are following this guide exactly) is the only configuration the solution has, and it is not recommended to add other configurations as Meson will just overwrite them the next time it regenerates the solution; instead, you have to generate separate build sites with Meson.

Important note: Using this method to build TPT, you may encounter the following errors at link time:

CVTRES : fatal error CVT1100: duplicate resource.  type:MANIFEST, name:1, language:0x0409
LINK : fatal error LNK1123: failure during conversion to COFF: file invalid or corrupt

This is caused by a bug in older versions of Meson triggered by this commit, which adds a manifest resource to the executable. The problem is that VS also tries to add its own default manifest to the executable because Meson does not instruct it otherwise.

This has been fixed in Meson and works correctly in version 1.4.0. You can upgrade Meson with

python -m pip install --upgrade meson

If for some reason you do not have access to this version, you can either build TPT differently (see the MSVC guide above) or temporarily remove this line of code (making sure to not commit its removal to Git), which is not critical for testing your builds.

With MinGW

Tested on Windows 10. This section applies to commit bc9d43bb103e and onward. See the previous version of this section for a guide on how to build earlier revisions.

MinGW is a package that makes it possible to build TPT with GCC even on Windows. If you have no prior experience with MinGW, the recommended way to build is with MSVC, see the relevant guide above. If you do have prior experience, you probably have your reasons for preferring MinGW over MSVC; this guide makes no effort to list possible ones.

NOTE: For MinGW, we only provide 64-bit prebuilt libraries.

NOTE: We use, recommend, and provide prebuilt libraries built with the flavour of MinGW that comes with the UCRT64 environment of Msys2. Using other flavours, including mixing our prebuilt libraries with such flavours, is something we have no resources to support.

Required environment setup

• install Msys2 (get it here)
• open a command prompt (search for "ucrt64" in the Start Menu, click the most sensible result)
  • it is recommended to pin the resulting window to your taskbar; you will be using this a lot to build TPT
• make sure your package lists are up to date (e.g. pacman -Sy)
  • this step may recommend you to close and re-open the command prompt; do it
• install a C++ compiler (e.g. pacman -S --needed mingw-w64-ucrt-x86_64-gcc)
• install git (e.g. pacman -S --needed git)
• install Meson (should automatically install Ninja) (e.g. pacman -S --needed mingw-w64-ucrt-x86_64-meson)
• optionally, install ccache (e.g. pacman -S --needed mingw-w64-ucrt-x86_64-ccache)
• install a library utility (e.g. pacman -S --needed mingw-w64-ucrt-x86_64-pkgconf)
• install required libraries (e.g. pacman -S --needed mingw-w64-ucrt-x86_64-{bzip2,luajit,jsoncpp,curl,SDL2,libpng,fftw})
  • if for some reason you cannot or do not want to use luajit, install your lua package of choice instead and set the lua build option accordingly; see Build options
• download the source code (e.g. git clone https://github.com/The-Powder-Toy/The-Powder-Toy)

Building for the first time

• cd to the repository root and execute the following commands

meson setup build-debug
cd build-debug
meson compile

• make sure Meson is using MinGW (look for mingw-w64-ucrt-x86_64-c++ in the log the setup step prints)
• you may see a few warnings throughout all of this, but no errors (if you do at any stage, do not try to skip it; ask us about it on the forum instead)
  • if you are not sure, run meson compile again; if it says "no work to do", everything worked fine
• if you get something along the lines of meson.build:110:2: ERROR: Include dir /usr/include does not exist, or if Meson otherwise complains about bzip2, see Elusive bzip2
• at this point, running TPT from the prompt should be possible

./powder

• note that this executable depends on the UCRT64 runtime and is very likely to only work properly when run the way described above, from the terminal

Compiling for MacOS

Tested on MacOS 10.15, 11.5, and 12.5.

Required environment setup

• install Homebrew (get it here)
• in a terminal, execute the following commands

brew install pkg-config luajit fftw sdl2 meson ninja bzip2 jsoncpp libpng
cd [wherever you keep your repositories]
git clone https://github.com/The-Powder-Toy/The-Powder-Toy

Building for the first time

• cd to the repository root and execute the following commands

meson setup build-debug
cd build-debug
meson compile

• make sure Meson is using Homebrew's Clang (look for clang in the log the setup step prints)
• you may see a few warnings throughout all of this, but no errors (if you do at any stage, do not try to skip it; ask us about it on the forum instead)
  • if you are not sure, run meson compile again; if it says "no work to do", everything worked fine
• if you get something along the lines of meson.build:110:2: ERROR: Include dir /usr/include does not exist, or if Meson otherwise complains about bzip2, see Elusive bzip2
• at this point, running TPT from the prompt should be possible

./powder

Compiling for Linux

Tested on Ubuntu 20.04 and Raspbian 10.

Required environment setup

• note that your package ecosystem may have wildly different names for the following packages
• make sure your package lists are up to date (e.g. sudo apt update)
• install a C++ compiler (e.g. sudo apt install g++)
• install git (e.g. sudo apt install git)
• install python, including pip (e.g. sudo apt install python3-pip)
• install Meson (e.g. sudo pip3 install meson)
• install Ninja (e.g. sudo pip3 install ninja)
• optionally, install ccache (e.g. sudo apt install ccache)
• install a library utility (e.g. sudo apt install pkg-config)
• install required libraries (e.g. sudo apt install libluajit-5.1-dev libcurl4-openssl-dev libssl-dev libfftw3-dev zlib1g-dev libsdl2-dev libbz2-dev libjsoncpp-dev libpng-dev)
  • if for some reason you cannot or do not want to use luajit, install your lua package of choice instead and set the lua build option accordingly; see Build options
• download the source code (e.g. git clone https://github.com/The-Powder-Toy/The-Powder-Toy)

Building for the first time

• cd to the repository root and execute the following commands

meson setup build-debug
cd build-debug
meson compile

• make sure Meson is using the toolchain you expect it to (read log the setup step prints)
• you may see a few warnings throughout all of this, but no errors (if you do at any stage, do not try to skip it; ask us about it on the forum instead)
  • if you are not sure, run meson compile again; if it says "no work to do", everything worked fine
• if you get something along the lines of meson.build:110:2: ERROR: Include dir /usr/include does not exist, or if Meson otherwise complains about bzip2, see Elusive bzip2
• at this point, running TPT from the prompt should be possible

./powder

Next steps (all platforms)

Updating the binary

Now that you have successfully built TPT for the first time, you will probably want to change things in the code. To update the binary so that it reflects these changes, build it again by executing

meson compile

in the same prompt you executed it the last time. You will have to do this every time you change something and want the binary to reflect the change.

Optimized builds

So far, you have been building "debug" binaries. These make debugging significantly easier than "optimized" builds, but they also offer less performance. You can instead build an "optimized" binary, which is much more performant, but very difficult to debug. Only use these builds when you are certain that you have no more bugs to take care of. If a bug does appear later on, go back to building debug binaries.

To build an optimized binary, navigate back to the root of the repository in your prompt and create a new build site with Meson, then build again

cd [whatever parameters that take you to your repositories, see above]
cd The-Powder-Toy
meson setup -Dbuildtype=debugoptimized build-optimized
cd build-optimized
meson compile

Note that build-debug and build-optimized directories are independent "build sites", each of which you can update with meson compile when you set them as your current directory (by using cd, see the lists of commands above).

Release builds

Both the debug and optimized configurations above produce "dynamic" binaries, which means they depend on certain components of your system (libraries you have installed with apt on linux or with brew on macos) or files other than powder.exe (DLLs in the same directory as powder.exe on windows). If you are a mod author, please make sure you are not shipping such binaries, as your users are used to TPT not depending on anything and thus are unlikely to have experience with installing these libraries on their own.

You can get rid of most of these dependencies by building a "static" binary. This way, the binary will depend on very basic components of your system that are very likely to be present. It will also gain a few megabytes and linking it will take longer, which is why you would only do this when you are about to release it to the public.

To build a static release binary, navigate back to the root of the repository in your prompt and create a new build site with Meson (see NOTE below!), then build again

meson setup -Dbuildtype=release -Dstatic=prebuilt build-release
cd build-release
meson compile

The "release" buildtype is identical to the "debugoptimized" buildtype, but it produces binaries without debug info. Debug info in static builds can take hundreds of megabytes, because it includes all the debug info from statically linked libraries. Unless you want to separate debug info later for some reason, it is best to get rid of it at compile time. Note that while debugoptimized builds are "only" very difficult to debug, release builds are virtually impossible.

NOTE: On Windows, if using MSVC, you will also need to add the -Db_vscrt=static_from_buildtype option to the Meson call above, otherwise the resulting binaries will be dynamically linked against the MSVC runtime (vcruntime.dll and similar).

meson setup -Dbuildtype=release -Dstatic=prebuilt -Db_vscrt=static_from_buildtype build-release
cd build-release
meson compile

NOTE: On Windows, if using MinGW, you will also need to add the -Dcpp_link_args="['-static','-static-libgcc','-static-libstdc++']" option to the Meson call above, otherwise the resulting binaries will be dynamically linked against the GCC runtime (libgcc_s_seh-1.dll and similar).

meson setup -Dbuildtype=release -Dstatic=prebuilt -Dcpp_link_args="['-static','-static-libgcc','-static-libstdc++']" build-release
cd build-release
meson compile

Note though that even such static builds will not be "fully static", as they will still import functions from msvcrt.dll. This is fine though, as this library is present on every modern install of Windows.

NOTE: On Windows, if using MinGW, -Db_lto=true is known to break static builds; use this setting at your own risk. The Meson configuration will throw a warning upon detecting this setting.

It used to work, but it broke

Each platform has its own set of quirks that need to be worked around (mostly looking at you, microsoft and apple). Fortunately, our build system takes care of most of these. Unfortunately, the workarounds come in the form of upgrades to the build system, which are not installed automatically, and even if they are, affected build sites may need to be reconfigured manually. If you had at some point gotten TPT to build successfully, but since then your build sites somehow broke, you can try one of the following methods to fix them.

The most straightforward way to fix a single build site is to reconfigure it. To check if this worked, try running meson compile.

cd [whatever parameters that take you to your repositories, see above]
cd The-Powder-Toy
meson setup --reconfigure --wipe build-debug # or whatever you named your build site
cd build-debug
meson compile

You will have to do this with every broken build site.

If this does not help, you can upgrade pip, Meson and Ninja. Like when setting them up for the first time, add sudo -H on Linux and MacOS, and run this in an elevated command prompt on Windows.

python -m pip install --upgrade pip # if you get "No module named pip", try python3
python -m pip install --upgrade meson ninja

Once you are done with this, reconfigure your build sites (see above).

If not even this helps, that is your cue to start from scratch, following the guide as if you are building TPT for the first time, except you already have the repository, so you do not need to clone that again. In fact, this is where your changes to TPT are stored, so you should never delete it. Deleting your local clone of the repository never solves any problem, it only results in loss of code. Do not even consider doing it.

As a last resort, you can ask us on the forum.

Troubleshooting

Meson not recognized as a command on Windows

If you have installed Python and Meson but when you try to run meson, Windows tells you that it is not a recognized command, you probably did not allow Python to add itself to your PATH environment variable. This guide will help you fix that. Once you are done with the steps there, make sure to restart every instance of the command prompt before trying to run meson again.

Elusive bzip2

If you use a package ecosystem whose bzip2 package does not provide a pkg-config file (sadly, this is the norm; this includes the package ecosystems of most Linux distributions, Homebrew for all platforms, and Msys2), you may need to add -Dworkaround_elusive_bzip2=true to Meson calls above. With this setting enabled, our Meson configuration will try to look for bzip2 at a few hardcoded locations, which should be enough for build site configuration to succeed.

If you still get errors, the hardcoded paths were probably wrong, and you will have to specify the correct include directory (workaround_elusive_bzip2_include_dir option), library path (workaround_elusive_bzip2_lib_dir option), and static property (whether you want to link against dynamic or static bzip2, workaround_elusive_bzip2_static); see Build options.

Example elusive bzip2 settings for Homebrew on M1 MacOS: -Dworkaround_elusive_bzip2=true -Dworkaround_elusive_bzip2_lib_dir=/opt/homebrew/Cellar/bzip2/1.0.8/lib -Dworkaround_elusive_bzip2_include_dir=/opt/homebrew/Cellar/bzip2/1.0.8/include -Dworkaround_elusive_bzip2_static=true

Example elusive bzip2 settings for Msys2 UCRT64: -Dworkaround_elusive_bzip2=true -Dworkaround_elusive_bzip2_include_dir=/ucrt64/include -Dworkaround_elusive_bzip2_lib_dir=/ucrt64/lib

Build options

Build options are passed to Meson at when you set up a build site (see examples above) or at any later time, when the build site is already in use. In both cases, they are passed as command line arguments of the form -D[name]=[value]. For example, to set up a build site that compiles TPT with Lua 5.1 instead of LuaJIT, you would issue the following command

meson setup -Dlua=lua5.1 build-debug-lua5.1

But you could also take an existing build site and change the relevant build option to do the same

cd build-debug
meson configure -Dlua=lua5.1

The next time you run meson compile, everything that needs to be rebuilt as a result of this change will be rebuilt. See the Meson quick guide for more on configuring build sites.

Below is a list of build options our Meson setup supports