I’m researched the subjet (render text as 3D objects, not texture) and found the some library but it very old:
OGLFT - last update 2012-12-10
FTGL - last update 2013-05-30
may be use OGRE?
which library is relevant today?
Apart from the Windows® 3D text screen saver there are probably not that many use cases and hence not that much of an interest in developing those libraries.
(I’m interested, what do you need this for?)
If you don’t want to use OGLFT and FTGL, you could use FreeType directly to extract, tesselate and extrude glyph outlines. I don’t see why you expect a lot of
development on the libraries that do that, since that isn’t really a rapidly changing field. Having their last changes around 2013/2012, I guess they support
GL 3.x+ core API? Perhaps they could profit from a programmable tesselation unit that GL 4.x offers. Do they support them? Do you need that?
Did you actually take a look at OGRE? OGRE is not a text rendering engine. OGRE is a full blown 3D graphics engine on top of OpenGL® and Direct3D®.
It is humongous in size and feature set and on a whole different level than working with OpenGL® directly. It abstracts that away and offeres generic, real-time
3D graphics rendering.