A blank string to FindPythonInterp finds the version
of Python that the system "python" interpreter invokes,
so this means the default is now the system default.
This removes the requirement that it only be included
in a single C++ file per library, by forcing the compiler
to emit the function that references the version symbol
as a weak symbol itself. Now, the linker will not only
tolerate redundant inclusions, it will also coalesce them
together.
To access a WeakPointerTo in a thread-safe way, use something like this:
if (auto ptr = weak_ptr.lock()) {
..use ptr as regular PointerTo
}
The new implementation no longer needs a reference to be stored to all weak pointers on the WeakReferenceList; a mere count of weak pointers is sufficient. Therefore, callbacks theoretically no longer require a WeakPointerTo to be constructed.
The WeakPointerTo class is not actually atomic; it could be made so, but I don't believe it's worth it at this time.
Many thirdparty libraries rely on __file__ being set properly, for example to be able to locate data files, so it is easiest to just set this to something remotely sensible (like the executable path).
This is still not a perfect solution, since eg. the wrong version of a package may still be used if older versions are still in the __whl_cache__ directory. We may want to look into using pip to resolve the package versions, or do something clever such as automatically remove cached wheels if a newer version of the same package was downloaded.
This allows using a coroutine to build up a more complex sequence including transitions (eg. scripted cutscene), as well as provide a standard way to register callbacks upon completion of the transition.
We don't guarantee a specific order in this case, especially because they can be run in either order if there is more than one thread, but it is still useful to have a defined order for single-threaded task chains. To that end, tasks
are now run in the order in which they were added to taskMgr.add (in absence of any other ordering constraints).
Fixes#309
