Earlier quoted context omitted.
I learned the basics of OpenGL from NeHe many years ago, and while things have gotten better, I can't recommend the site anymore. It's all written for old-school OpenGL (3 and below) and is generally a compendium of what you shouldn't do when writing OGL code. I still love it, but it's a bad resource for people new to OGL.
What's better?
Re: WebGL Path Tracing
#31The Orange Book, Red Book, Lighthouse3d tutorials, and general experimentation. One nice thing about WebGL is that the cruft is largely gone, due to its ES parentage. This means that a lot of old tutorials are completely irrelevant, but that you can safely use just about everything without running into horrible practices. (Not that there aren't plenty of pitfalls left.)