Thank you for considering Shaderc development! Please make sure you review CONTRIBUTING.md for important preliminary info.
Building
Instructions for first-time building can be found in README.md. Incremental build after a source change can be done using ninja (or cmake --build) and ctest exactly as in the first-time procedure.
Code reviews
(Terminology: we consider everyone with write access to our GitHub repo a project member.)
All submissions, including submissions by project members, require review. We use GitHub pull requests to facilitate the review process. A submission may be accepted by any project member (other than the submitter), who will then squash the changes into a single commit and cherry-pick them into the repository.
Before accepting, there may be some review feedback prompting changes in the submission. You should expect reviewers to strictly insist on the commenting guidelines -- in particular, every file, class, method, data member, and global will require a comment. Reviewers will also expect to see test coverage for every code change. How much coverage will be a judgment call on a case-by-case basis, balancing the required effort against the incremental benefit. But coverage will be expected. As a matter of development philosophy, we will strive to engineer the code to make writing tests easy.
Coding style
For our C++ files, we use the Google C++ style guide. (Conveniently, the formatting rules it specifies can be achieved using clang-format -style=google.)
For our Python files, we use the Google Python style guide.
Supported platforms
We expect Shaderc to always build and test successfully on the platforms listed below. Please keep that in mind when offering contributions. This list will likely grow over time.
| Platform | Build Status |
|---|---|
| Android (ARMv7) | Not Automated |
| Linux (x86_64) |  |
| Mac OS X | |
| Windows (x86_64) |
glslang
Some Shaderc changes require concomitant changes to glslang. It is our policy to upstream such work to glslang by following the official glslang project‘s procedures. At the same time, we would like to have those changes available to all Shaderc developers immediately upon passing our code review. Currently this is best done by maintaining our own GitHub fork of glslang, landing Shaderc-supporting changes there*, building Shaderc against it, and generating pull requests from there to the glslang’s original GitHub repository. Although a separate repository, this should be treated as essentially a part of Shaderc: the Shaderc master should always** build against our glslang fork's master.
Changes made to glslang in the course of Shaderc development must build and test correctly on their own, independently of Shaderc code, so they don‘t break other users of glslang when sent upstream. We will periodically upstream the content of our fork’s master branch to the official glslang master branch, so all the contributions we accept will find their way to glslang.
We aim to keep our fork up to date with the official glslang by pulling their changes frequently and merging them into our master branch.
*: Please note that GitHub uses the term “fork” as a routine part of contributing to another project, not in the sense of scary open-source schism. This is why you‘ll hear us speak of “our fork” and see “forked from KhronosGroup/glslang” atop the google/glslang GitHub page. It does not mean that we’re divorcing our glslang development from the original -- quite the opposite. As stated above, we intend to upstream all our work to the original glslang repository.
**: with one small exception: if a Shaderc and glslang pull requests need each other and are simultaneously cherry-picked, then a HEADs inconsistency will be tolerated for the short moment that one has landed while the other hasn't.