glad VS ImGuizmo

there's glad (https://github.com/Dav1dde/glad) which you can use as a single .c file + .h header that defines OpenGL stuff or a single header-only file. I use it on all of my OpenGL projects!

If you run into a similar issue with another extension, you need to manually add extensions when generating the GLAD loader.

GLEW/GLAD: Libraries that manage and give access to OpenGL functions and extensions. The difference is that GLAD allows for greater flexibility & customization for more recent versions of OpenGL. However, the Udemy course that I'm following uses GLEW and at least at this point, I prefer to follow along with the tools that each resource recommends.

I downloaded glad from this website : http://glad.dav1d.de/ I was also referring to this tutorial to setup my project : https://learnopengl.com/Getting-started/Creating-a-window

Not sure what you're asking, what is your end goal? If you opt for glfw look at the glfw docs: https://www.glfw.org/documentation.html and/or https://github.com/Dav1dde/glad/blob/glad2/example/c/gl_glfw.c for GLAD

Just link to GLAD if you're going to link to it! https://github.com/Dav1dde/glad

glew is a GL extension/loading library, OP didn't write glew, personally I use GLAD (https://glad.dav1d.de/) in my projects, which is pretty much the same thing but auto-generated for you based on your project requirements.

In general nobody really uses the gl headers because they are super outdated and, i believe, only use Microsoft's software renderer for OpenGL. You should use a OpenGL function loader like GLAD instead.

Just use a library like glad which loads everything at runtime under the hood (even system OpenGL runtime, no need to link anything). For a quick start, there is a website to generate headers and a single glad.c to put in your project: https://glad.dav1d.de/

If you're also using Dear ImGui then you can take a look at ImGuizmo (https://github.com/CedricGuillemet/ImGuizmo) Quite a nice library for this, works as an ImGui overlay so its very easy to integrate.

Although it's odd that the white circle is round and the others are not. I think it's a bug in ImGuizmo because I just tested it and the other Dear ImGui windows and widgets stay at the correct aspect ratio, so it's probably some value that's not being read correctly. Maybe open an issue on Github to let the autor know?

...but if you really want to do it yourself here's an example where they do that. If you want everything it winds up being pretty long.

You mention "Since no proper box-editing tool seems to exist, I had to write my own" in the blog; you might be interested to check out ImGuizmo based on Dear ImGui. Your own solution looks pretty decent though.