What does HackerNews think of pbrt-v3?

https://pbrt.org/

https://github.com/mmp/pbrt-v3

That said, IMHO, there is no "clean" C++ code. There are C++ codebases that use different styles, and their "quality" more or less is context sensitive.

Personally I felt the best tutorial to C++ were actually two other programming languages - Scheme and F#.

Scheme drove in the concept that it's totally fine to model things based on the shape of the data and that you don't need to create type based abstractions around every thing.

F# then demonstrated how a language with type system is supposed to work.

The problem with C++ is that the language is so verbose that unless you have an abbreviated model in your head how a type based language can be used to solve problems in best way, you will get lost in trivial C++ minutiae.

So, personally, I generally think "Am I solving a Scheme like problem or Standard ML like problem" and then try to apply C++ as simply as possible.

Several academics have created a career of how to patch C++/Java/C# with concepts that make them less fragile in a collaborative context:

https://en.wikipedia.org/wiki/Design_Patterns

https://www.amazon.com/Design-Patterns-Elements-Reusable-Obj...

In my opinion design patterns are not a fundamental concept, but rather provide common syntax for collaboration purposes for various patterns that are parts of language and more or less invisible in e.g. Scheme or F#. But if one is diving into C++ it's probably convenient to be familiar with these concepts.