Path Tracing Three Ways: A Study of C++ Styles by Matt Godbolt
Interactive version of the slides can be found at https://mattgodbolt.github.io/pt-three-ways-pres .
The entire presentation and code is also on two GitHub repositories:
https://github.com/mattgodbolt/pt-three-ways https://github.com/mattgodbolt/pt-three-ways-pres