How to write your own d3d9.dll for Skyrim?

Question

reverse engineering

Hello everyone, I played with mods and enb'shkami and met a large number of different d3d9.dll, which need to be thrown into the folder with skyrim.exe. And each of them had a different effect on the game. One removed the frame limit and turned off vsync, the other increased performance, etc.
The question is how to write your own d3d9.dll? How to google, where to look for info, how does this d3d9 work?
And is it possible to see other people's d3d9.dll?

Answer 1

Start started: https://docs.microsoft.com/en-gb/windows/desktop/d...