ocornut/imgui ? reverse-engineered prompt

I need to build a C++ library for creating simple user interfaces, specifically for game development tools and debug menus. The goal is to have something very lightweight that I can just drop into my existing C++ project without any external dependencies. It should be self-contained in just a few source files.

I want to be able to create UI elements like windows, buttons, sliders, and text inputs directly from my main game loop. For example, I'd call a function like SliderFloat("speed", &player_speed, 0, 100) and it would just work. This is for building developer tools to tweak variables or visualize data in real-time, not for the polished final UI for players. It should be fast, efficient, and renderer-agnostic, basically just giving me vertex buffers that I can render with my own engine.