- 📝 Posted:
- 🚚 Summary of:
- P0124, P0125
- ⌨ Commits:
- 💰 Funded by:
- Blue Bolt, [Anonymous]
- 🏷 Tags:
Turns out that TH04's player selection menu is exactly three times as complicated as TH05's. Two screens for character and shot type rather than one, and a way more intricate implementation for saving and restoring the background behind the raised top and left edges of a character picture when moving the cursor between Reimu and Marisa. TH04 decides to backup precisely only the two 256×8 (top) and 8×244 (left) strips behind the edges, indicated in red in the picture below.
These take up just 4 KB of heap memory… but require custom blitting functions, and expanding this explicitly hardcoded approach to TH05's 4 characters would have been pretty annoying. So, rather than, uh, not explicitly hardcoding it all, ZUN decided to just be lazy with the backup area in TH05, saving the entire 640×400 screen, and thus spending 128 KB of heap memory on this rather simple selection shadow effect.
So, this really wasn't something to quickly get done during the first half
of a push, even after already having done TH05's equivalent of this menu.
But since life is very busy right now, I also used the occasion to start
addressing another code organization annoyance: master.lib's single
master.h header file.
- Now that ReC98 is trying to develop (or at least mimic) a more type-safe C++ foundation to model the PC-98 hardware, a pure C header (with counter-productive C++ extensions) is becoming increasingly unidiomatic. By moving some of the original assumptions about function parameters into the type system, we can also reduce the reliance on its Japanese-only documentation without having to translate it
- It's far from complete with regards to providing compile-time PC-98 hardware constants and helpful types. In fact, we started to add these in our own header files a long time ago.
- It's quite bloated, with at least 2800 lines of code that
#included into the vast majority of files, not counting
master.h's recursively included C standard library headers. PC-98 Touhou only makes direct use of a rather small fraction of its contents.
- And finally, all the DOS/V compatibility definitions are especially
useless in the context of ReC98. As I've noted
📝 time and
📝 time again, porting PC-98 Touhou to
IBM-compatible DOS won't be easy, and
MASTER_DOSVwon't be helping much. Therefore, my upstream version of ReC98 will never include all of master.lib. There's no point in lengthening compile times for everyone by default, and those will be getting quite noticeable after moving to a full 16-bit build process.
(Actually, what retro system ports should rather be doing: Get rid of master.lib's original ASM code, replace it with readable, modern C++, and then simply convert the optimized assembly output of modern compilers to your ISA of choice. Improving the landscape of such assembly or object file converters would benefit everyone!)
So, time to start a new
master.hpp header that would contain
just the declarations from
master.h that PC-98 Touhou
actually needs, plus some semantic (yes, semantic) sugar. Comparing just
master.h to just the new
after roughly 60% of the transition has been completed, we get median
build times of 319 ms for
master.h, and 144 ms for
master.hpp on my (admittedly rather slow) DOSBox setup.
As of this push, ReC98 consists of 107 translation units that have to be compiled with Turbo C++ 4.0J. Fully rebuilding all of these currently takes roughly 37.5 seconds in DOSBox. After the transition to
master.hpp is done, we could therefore shave some 10 to 15
seconds off this time, simply by switching header files. And that's just
the beginning, as this will also pave the way for further
#include optimizations. Life in this codebase will be great!
Unfortunately, there wasn't enough time to repay some of the actual
technical debt I was looking forward to, after all of this. Oh well, at
least we now also have nice identifiers for the three different boldface
options that are used when rendering text to VRAM, after procrastinating
that issue for almost 11 months. Next up, assuming the existing
subscriptions: More ridiculous decompilations of things that definitely
weren't originally written in C, and a big blocker in TH03's