This can't work as on deserialize it would need to have the type for IUserData already.
And that's impossible with the way it's used right now.
Would need some kind of factory or so probably, but I'll ignore this for now.
Note that it's still possible to call some serialization manually on the derived classes by adding it there if needed.
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6568 dfc29bdd-3216-0410-991c-e03cc46cb475
Irrlicht generally avoided user pointers in the past, but after trying all kind of ugly workarounds - this is just easier and
not that much downsides really. Tiny speed costs due to additional SMaterial memory size and new comparison tests.
But allows to keep SMaterial alive and useful for a while longer without needing a complete rewrite and it can now be used for stuff like writing PBR shaders.
Using a new interface io::IUserData for this which also allows serialization the user data (that part is untested so far, sorry)
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6567 dfc29bdd-3216-0410-991c-e03cc46cb475
