Icosphere mesh generation at compile time?

[bitrex]

Is there any way to use C++11 templates/recursion to adapt the following
algorithm for generating the index/face mesh of an "icosphere"
(icosahedron-derived sphere geometry) such that the structures are
populated for a given recursion depth at compile-time, rather than runtime?

<https://schneide.wordpress.com/2016/07/15/generating-an-icosphere-in-c/>

[Rick C. Hodgin]

You could write a preprocessor, which takes prog1.cpp, runs it through
the preprocessor and sees a keyword like this: "ico<4>" and does the
compute part creating source code for the tesselation data at that
point, generating prog1_out.cpp, which is the version compiled.

It's how I would do it.

Thank you,
Rick C. Hodgin

[David Brown]

I haven't looked at in detail, but your key is likely to use C++14, not
just C++11, and constexpr functions. (C++14 gives you a lot more
flexibility in constexpr functions.) This will be more efficient than
using recursive templates.

[bitrex]

Thanks, I recall reading that C++14 does allow more flexibility, i.e.
constexpr functions can be more than essentially just a single "return
blah" statement.

Seems like the ability to simply jot down some recursive functions as
one would using regular runtime C++ but being able to just let the
compiler know to evaluate them at compile time as well (assuming the
arguments are say, template arguments known at compile-time) would be
really nice...