This PR adds a feature to merc2 to update vertices. This will be needed
to efficient do effects like blerc/ripple/texture scroll. It's enabled
for blerc in jak 1 and jak 2, but with a few disclaimers:
- currently we still use the mips2c blerc implementation, which is slow
and has some "jittering" because of integer precision. When porting to
PC, there was an additional synchronization problem because blerc
overwrites the merc data as its being read by the renderers. I _think_
this wasn't an issue on PS2 because the blerc dma is higher priority
than the VIF1 DMA, but I'm not certain. Either way, I had to add a mutex
for this on PC to avoid very slight flickering/gaps. This isn't ideal
for performance, but still beats generic by a significant amount in
every place I tested. If you see merc taking 2ms to draw, it is likely
because it is stuck waiting on blerc to finish. This will go away once
blerc itself is ported to C++.
- in jak 1, we end up using generic in some cases where we could use
merc. In particular maia in village3 hut. This will be fixed later once
we can use merc in more places. I don't want to mess with the
merc/generic selection logic when we're hopefully going to get rid of it
soon.
- There is no support for ripple or texture scroll. These use generic on
jak 1, and remain broken on jak 2.
- Like with `emerc`, jak 1 has a toggle to go back to the old behavior
`*blerc-hack*`.
- In most cases, toggling this causes no visual differences. One
exception is Gol's teeth. I believe this is caused by texture coordinate
rounding issues, where generic has an additional float -> int -> float
compared to PC merc. It is very hard to notice so I'm not going to worry
about it.
Running reference tests/decompiler should now be possible on macos
(arm). Most of the changes were just cleaning up places where we were
sloppy with ifdefs, but there were two interesting ones:
- `Printer.cpp` was updated to not use a recursive function for printing
lists, to avoid stack overflow
- I replaced xxhash with another version of the same library that
supports arm (the one that comes in zstd). The interface is C instead of
C++ but it's not bad to use. I confirmed that the extractor succeeds on
jak 1 iso so it looks like this gives us the same results as the old
library.
