Book Two: [hittable_list.h] Hittable list with bounding box

[dafhi]

Master branch

'i' was not declared ..
if (!objects[i]->bounding_box(t0, t1, temp_box))

[hollasch]

for (const auto& object : objects) {
    if (!objects[i]->bounding_box(t0, t1, temp_box))
        return false;
    output_box = surrounding_box(output_box, temp_box);
}

should be

for (const auto& object : objects) {
    if (!object.bounding_box(t0, t1, temp_box))
        return false;
    output_box = surrounding_box(output_box, temp_box);
}

Reviewing this code, I don't understand why this method doesn't ignore false returns, and just return false only if none of the objects has a bounding box.

[trevordblack]

It looks like it's correct in the source, but not in the html.

as for:

I don't understand why this method doesn't ignore false
returns, and just return false only if none of the objects
has a bounding box

I'm not entirely sure. A return of false for bounding_box means that an aabb isn't defined for that object.

I think returning false is for two reasons

1. Strictness. An underdefined hittable is not allowed
2. We don't have a way to combine no aabb and 1 aabb, instead of false you would need to keep track of if temp_box has been defined, if the current hittable has an aabb, and when to combine the two. It's actually a bit complicated