Yeah, there's kind of a reason why AAA games have a lot of people working on it: programming is really hard. It takes years to even be competent at coding, and more years still to be able to handle coding for closed-source proprietary hardware using only third-party tools and fan-made partial...
https://bugs.scummvm.org/ticket/12598
I have a ticket up on Grim Fandango, if anyone is interested. From what I've been looking at, at least in that game's case, it might not be anything to do with TinyGL