TR2X/CONTRIBUTING.md

Development guidelines

Build workflow

• Compile the project (described in the next section)
• Copy all .dll and .exe files from build/ to your game directory
• Copy the contents of data/ship/ to your game directory

Compiling

Compiling on Ubuntu

• With Docker:

  Make sure to install Docker and just, then run just. The binaries should appear in the build/ directory. To see list of possible build targets, run just -l.

• Without Docker:

  This scenario is not officially supported, but you can see how it's done by examining the files in the tools/docker/ directory for the external dependencies and meson.build for the local files, then tailoring your system to match the process.

Compiling on Windows

• Using WSL:

  Install WSL (video guide: https://www.youtube.com/watch?v=5RTSlby-l9w)

  • Run Powershell as Administrator
  • Copy and paste the following command: Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Windows-Subsystem-Linux
  • Restart the computer
  • Go to Windows App Store
  • Install Ubuntu

  Run WSL and continue with the instructions from the Compiling on Ubuntu section.

Supported compilers

Please be advised that any build systems that are not the one we use for automating releases (= mingw-w64) come at user's own risk. They might crash or even refuse to compile.

Working with the project

Top values

• Compatibility with the original game's look and feel
• Maintainability
• Automation where possible
• Documentation (git history and GitHub issues are great for this purpose)

Automatic code formatting

This project uses pre-commit to make sure the code is formatted the right way. This tool has additional external dependencies: clang-format for automatic code formatting and include-what-you-use to remove unused #includes. To install pre-commit:

python3 -m pip install --user pre-commit
pre-commit install

To install required external dependencies on Ubuntu:

apt-get install -y iwyu clang-format-18

After this, each time you make a commit a hook should trigger to automatically format your changes. Additionally, in order to trigger this process manually, you can run just lint-format. This doesn't include the slowest checks that would hinder productivity – to run the full process, you can run just lint. If for any reason you can't install the above software on your machine, our CI pipeline will still show what needs to be changed in case of mistakes.

Coding convention

While the existing source code does not conform to the rules because it uses the original Core Design's naming, new code should adhere to the following guidelines:

• Variables are lower_snake_case
• Global variables are g_PascalCase
• Module variables are m_PascalCase
• Function names are Module_PascalCase
• Macros are UPPER_SNAKE_CASE
• Struct names are UPPER_SNAKE_CASE
• Struct members are lower_snake_case
• Enum names are UPPER_SNAKE_CASE
• Enum members are UPPER_SNAKE_CASE

Try to avoid global variables, if possible declare them as static in the module you're using them. Changes to original game functionality most often should be configurable.

Other things:

• We use clang-format to automatically format the code

• We do not omit { and }

• We use K&R brace style

• We condense if expressions into one, so:

  if (a && b) {
  }
  

  and not:

  if (a) {
      if (b) {
      }
  }
  

  If the expressions are extraordinarily complex, we refactor these into smaller conditions or functions.

Submitting changes

We commit via pull requests and avoid committing directly to develop, which is a protected branch. Each pull request gets peer-reviewed and should have at least one approval from the code developer team before merging. We never merge until all discussions are marked as resolved and generally try to test things before merging. When a remark on the code review is trivial and the PR author has pushed a fix for it, it should be resolved by the pull request author. Otherwise we don't mark the discussions as resolved and give a chance for the reviewer to reply. Once all change requests are addressed, we should re-request a review from the interested parties.

Changelog

We keep a changelog in CHANGELOG.md. Anything other than an internal change or refactor needs an entry there. Furthermore, new features and OG bugfixes should be documented in README as well.

Commit scope

Either you can make a lot of throwaway commits such as 'test' 'continue testing' 'fix 1' 'fix 2' 'fix of the fix' and then squash your pull request as a whole, or you can craft a nice history with proper commit messages and then merge-rebase. The first case is mostly acceptable for isolated features, but in general we prefer the latter approach. As a principle, refactors should made in separate commits. Code review changes are best made incrementally and then squashed prior to merging, for easing the review process.

Commit messages

The most important thing to remember: bug fixes and feature implementations should always include the phrase Resolves #123. If there's no ticket and the pull request you're making contains player-facing changes, a ticket needs to be created first – no exceptions.

Anything else is just for consistency and general neatness. Our commit messages aim to respect the 50/72 rule and have the following form:

module-prefix: description in an imperative mood (max 50 characters)

Longer description of what happens that can span multiple lines. Each
line should be maximally 72 characters long, with the exceptions of
code/log dumps.

The prefix should describe the module that the pull request touches the most. In general this is the name of the .c or .h file with the most changes. Note that this includes the folder names which are separated with /. Avoid underscores (_) in favor of dashes (-).

The description should be as concise as possible; any details should be given in the commit message body. Use simple, to the point words like add, fix, remove, improve.

Good:

ui: improve resolution changing

Added the ability for the player to switch resolutions directly from
the game ui.

Resolves #123.

Great:

log: fix varargs for Log_Message()

On Linux, the engine crashes when printing the log messages. This
happens because the current code re-uses the same va_list variable on
two calls to vprintf() and vfprintf(). Actually, this is not allowed.
For using the same information on multiple formatting functions, it is
needed to create a copy of the primary va_list to a second one, by using
va_copy(). After rewriting properly the Log_Message() function, the
segmentation fault is gone. Tested on both Linux and Windows builds.

• This has no ticket number, but it was an internal change improving support for a platform unsupported at that time, which made it acceptable.

Bad:

ui: implemented the ability to switch resolutions from the ui

• the subject doesn't use imperative mood
• the subject is too long
• missing ticket number

Bad:

dart: added dart emitters to the savegame (#779)

dart: added dart emitters to the savegame

Add function for checking legacy savegame save flags
Resolves #774.

• it duplicates the subject in the message body
• the subject doesn't use imperative mood

When merging via squash, it's OK to have GitHub append the pull request number, but pay special attention to the body field which often gets filled with garbage.

Branching model

We have two branches: develop and stable. develop is where all changes about to be published in the next release land. stable is the latest release. We avoid creating merge commits between these two – they should always point to the same HEAD when applicable. This means that any hotfixes that need to be released ahead of unpublished work in develop are merged directly to stable, and develop needs to be then rebased on top of the now-patched stable.

Tooling

We try to code all of our internal tools in a reasonably recent version of Python. Avoid bash, shell and other similar languages.

Releasing a new version

New version releases happen automatically whenever a new tag is pushed to the stable branch with the help of GitHub actions. In general this is accompanied with a special commit docs: release X.Y.Z that assigns unreleased changes to a specific version. See git history for details.

Glossary

• OG: original game
• UK Box: the version released on discs in the UK
• Multipatch: the version released on Steam
• PS: PlayStation version of the game