Bug: rect hit returning NaN's, Infinities

[Walther]

raytracing.github.io/src/TheRestOfYourLife/aarect.h

Lines 124 to 126 in 7b92650

	auto t = (k-r.origin().y()) / r.direction().y();
	if (t < t0 || t > t1)
	return false;

If r.direction().y() happens to be zero, you'll get t=infinity. This infinity will get passed along, because infinity > infinity is false so the if branch is not taken.

Additionally, if k-r.origin().y() happens to be 0 as well, you'll get 0.0 / 0.0 resulting in a NaN that again gets passed along.

This exists in all three cases of rect, with different axes being the culprit.

Caveat emptor: I bumped into this in my Rust implementation, so some specific details may be slightly different, including in case infinity & NaN semantics are slightly different in C++. But I think this should be applicable.

---

Offtopic sidenote: wonder if it would be worth it to make the distance be named something else than t, considering some other functions in the book use t or t0, t1 for time

[hollasch]

Regarding the side note: see #678, currently in progress now resolved.

[hollasch]

See #756