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An open source remake of the CatSystem2 visual novel engine.

A makeshift demo of the current version can befound here.

Click/Scroll - Advance text

Ctrl/Enter - Advance text, hold to skip

SPACE - Hide message window

f - Toggle fullscreen

1-9 - Select choice

Shift + Alt +1-9 - Quick save to slot1-9

Shift +1-9 - Quick load from slot1-9

• Multi-platform (WASM, Windows SDL2)
• Raw KIF archive decryption
• HG-3 image decoding and caching
• Custom-built CatScene recursive-descent parser

FelineSystem2 implements a custom database of the game's KIF archives and assets, stored as a binary file.

• If statements must contain a whitespace after the closing parenthesis of the condition
  • if (#300==0) #(950+#300)=512
• Operators follow C-Style left-to-right precedence and associativity
• Integers and strings are the only data types that exist
  • #300=0
  • str 50 bg02
• Variable names can only be integers
• Variable names can be dynamically evaluated
  • #(950+#300)=512

• blend argument specifies the alpha value that the image will be displayed at
  • cg 0 blend 255 will display a completely opaque CG whilecg 0 blend 0 will display a completely transparent CG
• rdraw command after an image specifies the duration to fade to the target opacity
  • rdraw 30 will take30 frames to fade the image from alpha0 to the target alpha (e.g.255 by default)
  • Units are likely in frames at60fps (0.0167s/frame) regardless of the game's refresh rate setting
  • Anrdraw command will apply to all images within a script block (from a user input to the nextwait command)
• wait command without arguments will block until any time-based command completes
  • wait after ardraw 30 command will wait for the30 frames taken to completely fade in the images before proceeding to the next command
• wait with arguments behaves differently from standalonewait
  • wait 60 will block for60 frames before proceeding to the next command
  • wait 60 will not be aware of any time-based commands likerdraw and will not block untilrdraw completes
  • wait is sometimes used along withwait 60 consecutively
• cg 0 attr 1 (70+0) (80+0)
• cg 0 attr 2 (75+0) (85+0)
  • Assigns theBaseX,BaseY values of the specified imagecg 0 to the variables#(75+0) and#(85+0) respectively

• Trigger for creating such anamazingly comprehensive knowledgebase of the CS2 engine
• asmodean for being a pioneer in reversing the CS2 engine
• Dodder forHacking the Grisaia for localization
• koestl for his impeccable translations and contributions to localization