Book 3 code doesn't work if the glass ball is replaced with the original diffuse box

[hollasch]

The source code diverged from the listings in book 3, where listing 38 and image 9 had the original short box in the Cornell scene:

shared_ptr<hittable> box2 = make_shared<box>(point3(0,0,0), point3(165,165,165), white);
box2 = make_shared<rotate_y>(box2, -18);
box2 = make_shared<translate>(box2, vec3(130,0,65);
world.add(box2);

In the source code, this was changed without explanation to

auto glass = make_shared<dielectric>(1.5);
world.add(make_shared<sphere>(point3(190,90,190), 90 , glass));

If you substitute the original short box in the scene, you get a black image with only the square light source showing. Something's broken or hasn't been fully implemented in the source.

Note that pending PR #757 changes the book to reflect the current source, so shows a valid image with the glass sphere. The problem still remains, however.

[Walther]

(👍 Glad to find an issue posted on this, have spent a while trying to figure out where i have an implementation mistake in my code compared to the book.)

[trevordblack]

I believe my rewrites in #840 solve for this issue.

That said, the renders of book 3 still need to be redone.