Ren'Py development takes place on two branches, master and devel, as well as the occasional feature branch.
Master -----
The master branch contains code that can be run using the libraries in the latest (release or pre-release) version of Ren'Py. It's used for bugfixes and features that do not require C or Cython code to implement.
After checking out master, run:
./after_checkout.sh <path-to-renpy>to link in the libraries from the most recent Ren'Py. (On Windows, you will need to run this under msys or cygwin.)
Ren'Py can then be run by running renpy.exe, renpy.sh, or renpy.app as appropriate.
The devel branch contains code that requires a recompile of modules implemented in C or Cython. Building devel requires you to have the prerequisite libraries installed. Then set RENPY_DEPS_INSTALLED to a ::-separated list of paths containing dependencies. For example:
export RENPY_DEPS_INSTALL=/usr::/usr/lib/x86_64-linux-gnu/Finally, change into the modules directory, and run:
python setup.py installRen'Py can then be run by using python to run renpy.py.
For bug fixes, documentation improvements, and simple changes, just make a pull request. For more complex changes, it might make sense to file an issue so we can discuss the design.