xenia/.github/CONTRIBUTING.md

Content Guidelines

The issue tracker is exclusively for filing and discussing bugs, feature requests, and tracking work items. It is not for technical support or general discussion. Avoid discussing any illegal activity, such as downloading games.

Repeated misuses will result in a permanent project ban.

Information Sourcing

All information in xenia has been derived from reverse engineering legally-owned games, hardware, and tools made public by Microsoft (such as the XNA Game Studio tooling), scouring documentation made public by Microsoft (such as slide decks and other presentations at conferences), and information from code made public by 3rd party companies (like the Valve SDKs).

The official Microsoft Xbox Development Kits (XDKs) are not to be used for any information added to the project. The contributors do not want the XDKs, nor do they want any information derived from them. The challenge of the project is what makes it fun! Poisoning the codebase with code obtained by shady means could result in the project being terminated, so just don't do it.

Posting any information directly from an XDK will result in a project ban.

Contributing Code

Style Guide

Please read over style_guide.md before sending pull requests and ensure your code is clean as the buildbot (or I) will make you to fix it :) style_guide.md has information about using xb format and various IDE auto formatting tools so that you can avoid having to clean things up later, so be sure to check it out.

Basically: run xb format before you add a commit and you won't have a problem.

Referencing Sources

In code interacting with guest interfaces or protocols, where applicable, please leave comments describing how the information included in it was obtained. For code based on analysis of the response of the original Xbox 360 hardware or software, please provide reproduction information, such as an outline of the algorithm executed, arguments and results of function calls or processor instructions involved, GPU or XMA commands and state register changes. Having traceable sources helps solve multiple issues:

• The legality of the submitted code can be verified easily.
• Additional analysis based on reproduction steps from prior research can be done to discover more details or to research the behavior of other related features.
• The accuracy and completeness of the information can be evaluated. Knowing whether something is ground truth about the console's behavior or an approximation (for example, based on similar functionality in Windows, the Qualcomm Adreno 200 GPU, AMD's desktop GPU architectures; the Direct3D 11.3 functional specification, which may be used as a generic fallback when no information specific to the Xenos or Direct3D 9 is available) may help avoid redoing work that has already been done if the findings are accurate, or making potentially wrong conclusions about related functionality if there's no certainty about the correctness of the information. In addition, it's useful to describe how complete the implementation of a feature is — such as edge cases checked and covered. If you are unsure if your code accurately reflects the behavior of the console, or you have deliberately made deviations due to the lack of prerequisites for an accurate implementation or for performance reasons (in case of the latter, it's recommended to provide both options, selectable with a configuration variable), or you just want more research to be done in the future, please leave a TODO comment in the format provided in style_guide.md.

If you have verified your code by checking the correctness of the behavior of a game, do not refer to it by its title trademark. To avoid unnecessary dependencies on third parties, instead, use the hexadecimal title ID number displayed in the title bar beside the name of the game. It's also recommended to avoid using proper names of game content if they can be replaced with easily understandable pointers not including them, such as "first mission", "protagonist", "enemy aircraft".

Do not leave any hard-coded references to specific games, even in title ID form, in any part of the user interface, including the configuration file. If you want to provide an example of a game where changing a configuration variable may have a noticeable effect, use a code comment near the declaration of the variable rather than its description string. Any game identifiers referenced in the user interface must be obtained only from information provided by the user such as game data files.

Also, do not put any conditionals based on hard-coded identifiers of games — the task of the project is researching the Xbox 360 console itself and documenting its behavior by creating open implementations of its interfaces. Game-specific hacks provide no help in achieving that, instead only complicating research by introducing incorrect state and hiding the symptoms of actual issues. While temporary workarounds, though discouraged, may be added in cases when progress would be blocked otherwise in other areas, they must be expressed and reasoned in terms of the common interface rather than logic internal to a specific game.

Clean Git History

Tools such as git bisect are used on the repository regularly to check for and identify regressions. Such tools require a clean git history to function properly. Incoming pull requests must follow good git rules, the most basic of which is that individual commits add functionality in somewhat working form and fully compile and run on their own. Small pull requests with a single commit are best and multiple commits in a pull request are allowed only if they are kept clean. If not clean, you will be asked to rebase your pulls (and if you don't know what that means, avoid getting into that situation ;).

Example of a bad commit history:

• Adding audio callback, random file loading, networking, etc. (+2000 lines)
• Whoops.
• Fixing build break.
• Fixing lint errors.
• Adding audio callback, second attempt.
• ...

Histories like this make it extremely difficult to check out any individual commit and know that the repository is in a good state. Rebasing, cherry-picking, or splitting your commits into separate branches will help keep things clean and easy.

License

All xenia code is licensed under the 3-clause BSD license as detailed in LICENSE. Code under third_party/ is licensed under its original license.

Incoming code in pull requests are subject to the xenia LICENSE. Once code comes into the codebase it is very difficult to ever fully remove so copyright is ascribed to the project to prevent future disputes such as what occurred in Dolphin. That said: xenia will never be sold, never be made closed source, and never change to a fundamentally incompatible license.

Any third_party/ code added will be reviewed for conformance with the license. In general, GPL code is forbidden unless it is used exclusively for development-time tooling (like compiling). LGPL code is strongly discouraged as it complicates building.