[imnes]

I wouldn't try to implement anything yourself. Use one of the game building toolkits already out there.

If you don't mind going vintage, this is one I used many years ago, it's for building 3D games similar to DOOM, for DOS. You might need a dos emulator to run it in if your OS is too new to support it. Fun to play with though.

https://archive.org/details/lukecool_gmail_GCS