Merge code from @shrinktofit that allows control over where temporary files are created.
(Most commonly the .fbm directory where the SDK extracts embedded resources.)
With this, we are able to get rid of all the increasingly broken file
system utility code, and trust boost::filesystem to handle all the
cross-platform complexity.
The first version of this PR centred around C++17 & std::filesystem,
but support remains too elusive; it seems works out of the box in
Visual Studio (especially 2019), but is entirely missing from the Mac
dclang, and even with GCC 8.0 it requires an explicit '-l c++fs'.
Luckily the std:: version is almost exactly the boost:: version (not
surprising) so when the world's caught up, we can ditch Boost and go
all stdlib.
Setting up Conan requires a bit of work; we'll want to document the
details in the README.
We want to move to auto-formatting all our code, and it just seemed impossible
to make cxxopts usage tidy under clang-format's dominion. While trying to work
out its quirks, I realised that CLI11 did everything I wanted much better, and
so we've switched.
We're also going to chuck the usage of ExternalProject_Add(), at least for the
simplest use cases such as single-header include files. We'll just commit them
directly; that's kind of the whole point.
The one discipline we'll maintain is that commits that involve third_party/
should be as self-contained as possible (without breaking the app).
This finishes the first phase of the FBX2glTF refactor, breaking utility classes out where things were getting too monolithic.
There is an equally important cleanup phase coming where we wrench all the various parts of this code, including the historical ones that we've rarely touched as yet, into a single C++ style paradigm, and modernise everything to C++11 at least.
But for now, we're just picking the pieces back on the floor so we can push 0.9.6 out. It's been far too long since a release.
Did not mean to commit/push the current state of master. But rather than
mess up source control history with a force push, I'll just try to hurry
to a stable point.
luzhuang
Pär Winzell
Leslie Leigh
Pär Winzell
Simon