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.
The special case doesn't appear to make a significant difference in any games, and the current implementation has a (minor, fixable) issue that breaks Super Mario Sunshine (both with a failed assertion (https://bugs.dolphin-emu.org/issues/11742) and a rendering issue (https://bugs.dolphin-emu.org/issues/7476)). Hardware testing wasn't able to reproduce the special case, either, so it may just not exist.
PR #9315 contains a fixed implementation of the special case on all video backends, and can serve as a basis for it being reintroduced if it is found to exist under more specific circumstances. For now, I don't see a reason to keep it present.
Cel-damage uses the color from the lighting stage of the vertex pipeline
as texture coordinates, but sets numColorChans to zero.
We now calculate the colors in all cases, but override the color before
writing it from the vertex shader if numColorChans is set to a lower value.
The casts to u32* are technically undefined behavior. The u8* cast is
left, as char/unsigned char is exempted from this rule to allow for
bvtewise inspection of objects (and this is what s8/u8 are typedefs of
on platforms we support).
This moves all the byte swapping utilities into a header named Swap.h.
A dedicated header is much more preferable here due to the size of the
code itself. In general usage throughout the codebase, CommonFuncs.h was
generally only included for these functions anyway. These being in their
own header avoids dumping the lesser used utilities into scope. As well
as providing a localized area for more utilities related to byte
swapping in the future (should they be needed). This also makes it nicer
to identify which files depend on the byte swapping utilities in
particular.
Since this is a completely new header, moving the code uncovered a few
indirect includes, as well as making some other inclusions unnecessary.
