Mastodawn

I think I am getting a hang on that "shadow" thing.

so far I found two ways of doing computer graphics:

- be smart, undertand all the math and just doing it right from the first try. Never works for me.

- keep adding debug visualisation until the problem is reduced to something trivial and accessible.

Maybe, one day, I'll learn enough to do stuff the smart way. Maybe..

The coolest thing about this demo - it has 15s clean compilation time.

"cargo clean && cargo run" takes 15s, on a an old t480.

Just "cargo run" usually takes ~0.5s.

Rust is crazy fast to compile!