# Embarrassed Shina-chan: Linux / Proton fix pack

Makes **Embarrassed Shina-chan~ the Naked Wandering College Girl** (Steam AppID
`2326780`, built with RPG Developer Bakin) run on Linux under Proton. Out of
the box the game reaches a grey/white screen and then freezes. Even once it
boots, the character sprites and all 2D menus are invisible. This pack applies
a set of small, documented, reversible fixes to your own copy so the game
boots, loads the full 3D map, and renders the characters, menus and UI.

![working screenshot](docs/working.png)

The bugs are in this older Bakin engine build (`kmyCore.dll` ~5.4 MB, v1.1.0).
Newer Bakin games run on the same Proton with no changes at all, since the
engine fixed these issues upstream. This pack backports that behaviour into
the older build.

## What it does not do

It ships no game files: no `kmyCore.dll`, no `bakinplayer.exe`, no shaders. It
only carries scripts and source that transform your installed copy, and it
verifies the original bytes and hashes before touching anything. Every change
is backed up and can be reverted with `uninstall.sh`.

## Requirements

- A Linux Steam install of the game, run through Proton (tested on Proton
  Experimental / 11).
- `gcc`, `patch`, `python3`, `od`/`dd` (standard on any desktop Linux).
- The .NET SDK (`dotnet`), only to build the ~30-line IL patcher for fix 2.
  The first build fetches Mono.Cecil from NuGet, so it needs network access
  once.

## Install

```bash
git clone <this-repo> && cd shina-linux-patch
./install.sh            # auto-detects the game, or pass its folder explicitly
```

Clone to a path without spaces or `:` (e.g. `~/shina-linux-patch`).
`LD_PRELOAD` cannot handle such paths and the installer refuses them.

Then, as the installer prints:

1. Steam -> the game -> Properties -> Launch Options:
   ```
   "/abs/path/to/launcher.installed.sh" %command%
   ```
2. Wayland only (keyboard focus): close the game fully, then
   ```
   bash patches/05-wayland-keyboard.sh "/path/to/.../Embarrassed Shina-chan~ ..."
   ```

Launch from Steam. Revert anytime: `./uninstall.sh "/path/to/...game folder"`.

## The fixes

| #  | Symptom | Root cause | What the fix does | Layer |
|----|---------|-----------|-------------------|-------|
| 1  | Grey screen, no models | `scanPlugin` reads the in-memory `data.rbpack` FS, which contains no `.dlp` asset loaders | 1-byte retarget of one `call` so it uses the on-disk FS creator | `kmyCore.dll` (native) |
| 2  | (same) no `.dlp` found | `Entry.initialize("", null)` makes the native path derivation fail under Wine | IL rewrite: pass `AppDomain.CurrentDomain.BaseDirectory` instead of `null` | `bakinplayer.exe` (managed) |
| 3  | White screen, "Vertex Attribute Problem", freeze | Mesa cross-stage DCE marks `vin_*` vertex inputs inactive, so `glGetAttribLocation` returns -1 | keep-alive term in the shader that references every input, scaled by a uniform Mesa can't fold to 0 | game GLSL (text) |
| 4a | Characters, menus and all 2D UI invisible | The engine sets up 2D-sprite/UI vertex attributes on the default VAO (0). Legal in an OpenGL compatibility profile, but Wine gives it a core profile where `glVertexAttribPointer` then fails with `GL_INVALID_OPERATION` and the driver rejects every default-VAO draw | `LD_PRELOAD` binds a real VAO whenever the game would use VAO 0 | host GL (preload) |
| 4b | Freeze right after the map loads | WASAPI init fails (`SndError 923`); a thread waits forever on an "audio ready" event | `LD_PRELOAD` caps INFINITE `NtWaitForSingleObject` at 10 s | Wine/ntdll (preload) |
| 5  | Mouse works, keyboard doesn't (Wayland) | Window uses ICCCM "Globally Active" input model; compositor withholds keyboard focus | Wine registry `UseTakeFocus=N` (passive model) | Wine registry |

Fixes 4a and 4b, plus the IBL BRDF LUT lighting texture, live in one small
`LD_PRELOAD` hook:
[`patches/04-runtime-hook/bakin_minimal.c`](patches/04-runtime-hook/bakin_minimal.c).
Fix 4a is the one that makes the characters and menus appear.

Full technical write-up: [docs/TECHNICAL.md](docs/TECHNICAL.md).

## How to review it

Everything is source or plain text:

- Fix 1, [`patches/01-kmycore-diskfs.sh`](patches/01-kmycore-diskfs.sh):
  verifies the full 5-byte `call` instruction (`e8 58 92 fd ff`) plus a hash
  check, then changes one byte (`0x58` to `0xB8`).
- Fix 2, [`patches/02-pluginpath/Program.cs`](patches/02-pluginpath/Program.cs):
  the Mono.Cecil IL rewrite, ~30 lines.
- Fix 3, [`patches/03-shader-vin-keepalive.patch`](patches/03-shader-vin-keepalive.patch):
  a unified diff of the shader include.
- Fixes 4a/4b, [`patches/04-runtime-hook/bakin_minimal.c`](patches/04-runtime-hook/bakin_minimal.c):
  the VAO fix is `ensure_vao()` plus the `glVertexAttribPointer` /
  `glEnableVertexAttribArray` / `glBindVertexArray` wrappers; the audio fix is
  the `NtWaitForSingleObject` splice; plus the IBL LUT drop.
- Fix 5, [`patches/05-wayland-keyboard.sh`](patches/05-wayland-keyboard.sh):
  a single registry value.

## How the VAO bug was found

Every observable GL state on the character's draw was identical to the visible
3D models: same program, framebuffer, thread, depth/blend/stencil/cull,
viewport, even the attached textures. Still, nothing rendered. The break was
found by calling `glGetError` immediately after the character's draw (it
returned `GL_INVALID_OPERATION`) and then installing a
`glDebugMessageCallback`, which reported the exact reason:
`glVertexAttribPointer(no array object bound)`. When a draw is invisible
despite matching a visible one in every state you can read, the draw itself
may be getting rejected; check `glGetError` on that draw and turn on GL debug
output.

## Known limitations

A few street props (`bus`, `Traffic light`, `Swing_ch1`, `ParkClock_ch1`, ...)
log a non-fatal "Vertex Attribute Problem" during map load and may show wrong
or missing texture mapping. The game runs at full speed and everything else,
including characters and UI, renders fine.

## Applying this to other Bakin games

Some of these fixes carry over to other games built on the same old Bakin engine
(the OpenGL build, `kmyCore.dll` around 5.4 MB). Others are tied to this one
game's files.

Newer Bakin games don't need any of this. They ship `kmyDX12.dll` and render with
DirectX 12 through vkd3d, which avoids the OpenGL bugs. The game 貢げ！女神様, on a
newer build, runs on Proton with no patches at all.

What carries over unchanged:

- The VAO fix, which is the main one. It's a plain LD_PRELOAD hook that binds a
  real VAO whenever the game uses the default VAO 0, and it never references this
  game. Load it into any old-Bakin OpenGL game under Wine or Proton and it should
  bring back the invisible characters, menus and UI. Any old OpenGL Windows game
  that assumes the default VAO in a Compatibility profile hits the same bug and
  takes the same fix.
- The audio wait cap and the Wayland `UseTakeFocus` registry value. Both act on
  Wine, not on the game.

What's tied to this build:

- Fix 1 (the one-byte `kmyCore.dll` edit) and Fix 2 (the `bakinplayer.exe` IL
  rewrite) are pinned to one `kmyCore.dll` (md5 `68590231...`). The same build
  patches the same way, a different version has different offsets. The scripts
  check the exact bytes and stop if they don't match, so running them on the wrong
  build does nothing bad. It just refuses.
- Fix 3 (the shader keep-alive) only applies if the game ships the same
  `v2_vpcommon.cgh`.
- The audio hook's `ntdll` offset (`0x5b530`) follows the Proton build, not the
  game.

To try it on another old-Bakin game:

1. Start with the hook by itself (VAO fix and audio cap). Change the hardcoded
   `APPID=2326780` in `install.sh` to the new game's ID so `@TMPBASE@` resolves to
   its prefix, then set the launcher as that game's launch options. This is
   usually enough to get the characters and menus back.
2. If the game also opens to a grey, empty scene, you also need fixes 1 and 2,
   with their offsets re-derived from that game's `kmyCore.dll`.
3. Fix 3 is only worth doing if the log fills with "Vertex Attribute Problem".

None of this is guaranteed on a build nobody has tested, but the VAO fix is
general enough to be the first thing to reach for.

## Legal

This exists for interoperability: making a legally purchased game run on
Linux. No copyrighted game content is redistributed; the tools operate on your
own files. The bundled `ibl_brdf_lut.bmp` is a standard precomputed BRDF
lookup table (the Karis split-sum function), not game content.
`bakin_minimal.c` and the scripts are MIT-licensed (see `LICENSE`). "RPG
Developer Bakin" and the game are trademarks of their respective owners.