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ReC98
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@rec98@nmlgc.net

About rec98

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https://rec98.nmlgc.net

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The Touhou PC-98 Restoration Project. Decompiled 100% of TH01 to provably legit C++ code, remaining games in progress. Which mods or ports do you want to see?

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Recent posts

exclude boosts

Finished the retirement part of the next blog post. >7,700 words with the full timeline, nuance, and plenty of burned bridges that hopefully close off any way back into this hellhole I should have left in 2011.

The vibecoders will soon appear like the sanest actors in the room.

OK, received tons of words, but zero serious offers to continue working in this scene in any capacity, matching the trend started in April.
Hence, this business model has run its course, I made the right call, and the decision is final.

First round of refunds has been sent out.

ReC98 will end after the next delivery.

I don't have it in me to compete with vibecoders, especially when y'all cheer them on for instantly delivering what you've wanted all along. And if you aren't cheering yet, you soon will; they're only getting better and more numerous.

Many thanks to this month's subscribers!

RL consumed lots of time this month. Regaining focus has been tough with the final steps being as difficult as ever.

Wondering how ReC98 can possibly survive after all the forks (many of them vibe-coded) I've seen in this month alone.

 Active ReC98 subscriptions for June 2026: • €125 from [Anonymous] towards anything (including tooling) • €50 from Ember2528 towards better replays for Shuusou Gyoku, followed by a long-term plan to first decompile TH03, adding replays, porting it to modern systems, and then implementing netplay (although we're also going for a more short-term option of having netplay on PC-98) • €35 from [Anonymous] towards TH03 RE • €10 from Root towards porting SDL to Windows 98 to get Shuusou Gyoku running there again

140-175 ms for simulating the full 7 minutes of Shuusou Gyoku's Extra Stage on the command line.

On an 8-year-old Core i5.
Single-threaded.
With MSVC's horrid codegen and several untapped optimization opportunities.

And that's the heaviest case. Regular stages are much faster.

 Output of the upcoming Shuusou Gyoku command-line replay simulation tool, showing the end result of two Extra Stage and one Lunatic Stage 4 replay, together with the surprisingly short amount of time it took to gather these results – 141.3 ms for a Wide Shot Extra Stage run, 173.3 ms for a Homing Missile Extra Stage run, and 44.8 ms for a Laser run of Stage 4 on Lunatic difficulty, translating to validation frame rates of 191894, 151244 and 242082 FPS, respectively.

Finally, Shuusou Gyoku's game logic, isolated in a reusable, freestanding DLL.

No global state.
No Win32 API dependencies besides GetProcessHeap(), HeapAlloc(), and HeapFree().
No instructions newer than i586.
Still simulates blazingly fast. (Have fun guessing how fast exactly!)

 Screenshot of the Windows 11 Properties dialog displaying the new Shuusou Gyoku game logic DLL, with a size of 73,216 bytes.
Screenshot of Dependency Walker running on Windows 98 displaying the new Shuusou Gyoku game logic DLL and showing off its minimal imports of GetProcessHeap(), HeapAlloc(), and HeapFree().

Many thanks to this month's subscribers!

The splitting process has escalated to not only cover Shuusou Gyoku's logic, but also my SDL-based engine, laying the groundwork for future modern-system builds.
Only missing the CLI now, and of course the blog post. Mid-June, maybe?

 Active ReC98 subscriptions for May 2026: • €125 from [Anonymous] towards anything (including tooling) • €50 from Ember2528 towards better replays for Shuusou Gyoku, followed by a long-term plan to first decompile TH03, adding replays, porting it to modern systems, and then implementing netplay (although we're also going for a more short-term option of having netplay on PC-98) • €35 from [Anonymous] towards TH03 RE • €10 from Root towards porting SDL to Windows 98 to get Shuusou Gyoku running there again

Full list of seemingly decorative aspects in Shuusou Gyoku that are actually game logic and must always be simulated because they draw from and advance the single global RNG:

  • The hearts shown when losing a life
  • The sparks shown when grazing bullets or hitting an enemy
 First Shuusou Gyoku comparison screenshot of the randomness in 1) the hearts shown when losing a life, and 2) the sparks shown when grazing bullets. Taken at the start of Stage 5.
Second Shuusou Gyoku comparison screenshot of the randomness in 1) the hearts shown when losing a life, and 2) the sparks shown when grazing bullets. Taken at the start of Stage 5.

Point items in Shuusou Gyoku will award negative points if you collect them below the bottom edge of the playfield during the respawn animation.

And nobody noticed because

  1. the game's 5×7-digit font doesn't have a - sign, and
  2. the total score can't decrease, only increase.

Many thanks to this month's subscribers!

Very slow month, but I still managed to move enough code to push the headless Shuusou Gyoku subproject to over 100 commits. Very close to solving the hardest issues while juggling Windows 9x and FFI use cases.

4 pushes for sure, though.

 Active ReC98 subscriptions for April 2026: • €125 from [Anonymous] towards anything (including tooling) • €50 from Ember2528 towards better replays for Shuusou Gyoku, followed by a long-term plan to first decompile TH03, adding replays, porting it to modern systems, and then implementing netplay (although we're also going for a more short-term option of having netplay on PC-98) • €35 from [Anonymous] towards TH03 RE • €10 from Root towards porting SDL2 to Windows 98 to get Shuusou Gyoku running there again

Debug builds of Shuusou Gyoku had a menu option that turns off collision detection.

Past tense because this forks gameplay, desyncs replays recorded with the opposite value, and is therefore very bad. I'll replace it with the alternative approach of just setting lives to 255.

 Screenshot of Shuusou Gyoku's Config → Difficulty menu in a build compiled with the PBG_DEBUG macro, showing pbg's four debug options, with the collision-detection-deactivating `Hit [O F F]` option highlighted. The help window describes it as 「[DebugMode] 当たり判定」.

Many thanks to this month's subscribers!

Untangling Shuusou Gyoku's game logic into a library isn't the worst thing in the world, but still nontrivial. Will definitely end up closer to 2 pushes than to 1.

Probably doing a bit of TH02 RE after that, given its recent funding.

 Active ReC98 subscriptions for March 2026: • €125 from [Anonymous] towards anything (including tooling) • €50 from Ember2528 towards better replays for Shuusou Gyoku, followed by a long-term plan to first decompile TH03, adding replays, porting it to modern systems, and then implementing netplay (although we're also going for a more short-term option of having netplay on PC-98) • €35 from [Anonymous] towards TH03 RE • €10 from Root towards porting SDL2 to Windows 98 to get Shuusou Gyoku running there again

🚚 TH03's enemy, fireball, explosion, chaining, and combo systems have been fully decompiled and researched!

Hardest piece of game logic in all of PC-98 Touhou, by far. 1% of overall code, 6% of TH03 itself.

🐞 1 bug
💣 5 landmines
🎺 8 quirks
🪨 61 pieces of bloat

 Screenshot of a video that visualizes TH03's frame data of a fireball-originating explosion against a pellet, demonstrating how these explosions are rendered 8 pixels lower than the position that collision detection uses for their hitbox. Taken from the ReC98 2026-03-16 blog post. The caption reads: "Thanks to the anonymous backer for providing the Anything budget for these multi-row tabs at the end of the 6th push!"
Screenshot of a video showcasing what happens when exceeding TH03's 40-enemy cap when constructing a formation sequence that starts with a 12-enemy formation followed by the 16-enemy "Four Lines of Four" formation. Demonstrates how closely timed bombs can reserve a majority of TH03's enemy slots for explosions, which prevents successive formations with high enemy counts from being spawned for one of the players, which in turn causes them to skip a lot of formations in its internal 256-formation cycle (29 in this example). Taken from the ReC98 2026-03-16 blog post.
Screenshot of a video showcasing how removing the enemy damage cap of TH03's explosions can change the timing and placement of explosions. Demonstrated by chaining formation #4 (Racetrack) and colorizing the resulting explosions based on the amount of damage they've dealt to enemies. The caption reads: "I chose black for explosions that currently can't deal damage to enemies. The other 6 colors (dark green, light green, dark red, light red, dark blue, and light blue to represent 0 to 5 dealt hits in this order) are TH03's regular in-game VRAM colors from #5 to #10." Taken from the ReC98 2026-03-16 blog post.
Screenshot of a video of a TH03 explosion destroying a fireball and spawning two red fireballs in response, recorded from 1:04 minutes into the Kotohime vs. Marisa demo on Kotohime's playfield. The caption reads: "Note how the "primary" new fireball described above is spawned from the center of its explosion, while the "additional" new fireball is spawned from the center of the explosion that caused the old fireball to explode." Taken from the ReC98 2026-03-16 blog post.