SayonaraUKHD​

a fully configurable graphics enhancement mod for Sayonara Umihara Kawase.

AI disclosure: This mod was developed through vibe coding. It was started with GPT-6 Astra, then handed over to Claude Opus 5.5, which reviewed, optimized, reorganized and extended it. The project's goals, direction and all in-game testing are by me.

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Features​

• HD internal rendering resolutions.
  no longer stuck at the PS Vita's rendering resolution
  you can manually set the resolution up to 7168 × 8192
• FXAA.
  anti-aliasing on the 3D scene only (the HUD stays sharp).
  Press F7 in game to compare it on and off.
  
  
  
• True aspect ratio.
  the game's built-in aspect-ratio slider normally just stretches a 16:9 image.
  SayonaraUKHD widens or heightens the actual view instead.
  The HUD and menus keep their original layout.
• Culling fix.
  objects that come into view at the newly visible screen edges are drawn instead of popping in.
  
  
• Texture dumping and replacement.
  save the game's textures, edit them at up to 8× their original size, and load your versions as PNG or DDS.
  
  

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Installing/Setup​

1. Download the mod (obviously).
2. Open the game folder: in Steam, right-click the game → Manage → Browse local files. It is the folder that contains UmiByeWin.exe.
3. Copy d3d11.dll and SayonaraUKHD.ini into that folder.
4. done.

Linux / Steam Deck notes​

• Recommended: on SteamOS and Bazzite, play in Game Mode. On a Linux desktop, run the game through gamescope, for example with this in the game's Properties → General → Launch Options(use your screen's resolution):
  gamescope -f -W 2560 -H 1440 -- %command%

To uninstall, delete d3d11.dll (and optionally SayonaraUKHD.ini, UmiGraphics.log and the Textures folder). On Linux, also remove any launch options you added for the mod.

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Notes​

You are allowed to use, modify and share this mod however you like, with or without credit.

i suck at this game, so i probably won't be updating this mod to add new features unless requested to.
but by all means let me know if something is wrong with the mod, or if there is something you want added.

oh and the reason i recommend playing in game mode or using gamescope on linux is because the normal fullscreen mode looks very bad on Linux normally.
i tested it both on Bazzite and on my Steam Deck.