I have hundreds of lines of old immediate mode OpenGL to update like this, because client thinks using a free 3D engine that could import the CAD models or assimp is “lame.”
😭😭😭😭 
Discussion
Lame? 🤔 Anyhow, as long as the client pays for it...
Same person told me “real programmers use C++”
It pays the bills. 🤷♂️