Robert Garrett
515f5b866a
Because of the mutable record being used in the loop, the previous version had a somewhat obscured way to track the nearest collision. Switching to an optional (so I can have a non-optional Material in it) means I'm not interrogating that value.... So it gets to be explicit again. I'll refactor the entire for-loop into an iterator with the min() adapter at some point. For now: Material lifetimes!
