SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
Now that we have an actual interface to manage things, we can stop
duplicating the calls to to the pixel shader manager and remove the
need to remember to actually do so when disabling or enabling the
bounding box.
Rather than expose the bounding box members directly, we can instead
provide an interface for code to use. This makes it nicer to transition
from global data, as the interface function names are already in
place.
