- 📝 Posted:
- 💰 Funded by:
- Touhou Patch Center
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So, where to start? Well, TH04 bullets are hard, so let's
procrastinate start with TH03 instead 
The 📝 sprite display functions are the
obvious blocker for any structure describing a sprite, and therefore most
meaningful PI gains in that game… and I actually did manage to fit a
decompilation of those three functions into exactly the amount of time
that the Touhou Patch Center community votes alloted to TH03
reverse-engineering!
And a pretty amazing one at that. The original code was so obviously
written in ASM and was just barely decompilable by exclusively using
register pseudovariables and a bit of goto, but I was able to
abstract most of that away, not least thanks to a few helpful optimization
properties of Turbo C++… seriously, I can't stop marveling at this ancient
compiler. The end result is both readable, clear, and dare I say
portable?! To anyone interested in porting TH03,
take a look. How painful would it be to port that away from 16-bit
x86?
However, this push is also a typical example that the RE/PI priorities can
only control what I look at, and the outcome can actually differ
greatly. Even though the priorities were 65% RE and 35% PI, the progress
outcome was +0.13% RE and +1.35% PI. But hey, we've got one more push with
a focus on TH03 PI, so maybe that one will include more RE than
PI, and then everything will end up just as ordered?