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https://github.com/kokseen1/felinesystem2
An open source remake of the CatSystem2 visual novel engine.
https://github.com/kokseen1/felinesystem2
adventure-game-engine c c-plus-plus catsystem catsystem2 emscripten galgame grisaia reverse-engineering sdl2 visual-novel visual-novel-engine visual-novel-framework wasm webassembly
Last synced: 3 months ago
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An open source remake of the CatSystem2 visual novel engine.
- Host: GitHub
- URL: https://github.com/kokseen1/felinesystem2
- Owner: kokseen1
- Created: 2022-09-08T06:01:46.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2023-06-01T13:10:59.000Z (over 1 year ago)
- Last Synced: 2024-10-12T16:29:03.765Z (4 months ago)
- Topics: adventure-game-engine, c, c-plus-plus, catsystem, catsystem2, emscripten, galgame, grisaia, reverse-engineering, sdl2, visual-novel, visual-novel-engine, visual-novel-framework, wasm, webassembly
- Language: C++
- Homepage: https://fruit.toori.tech
- Size: 425 MB
- Stars: 19
- Watchers: 3
- Forks: 2
- Open Issues: 17
-
Metadata Files:
- Readme: README.md
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README
#  FelineSystem2
An open source remake of the CatSystem2 visual novel engine.
## Demo
A makeshift demo of the current version can be [found here](https://fruit.toori.tech/).
## Controls
`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 slot `1-9`
`Shift` + `1-9` - Quick load from slot `1-9`
## Features
- Multi-platform (WASM, Windows SDL2)
- Raw KIF archive decryption
- HG-3 image decoding and caching
- Custom-built CatScene recursive-descent parser
## KIF Database Structure
FelineSystem2 implements a custom database of the game's KIF archives and assets, stored as a binary file.
### Archive Table
| Data Type | Value | Description |
| --------------: | :---------- | :------------------------------------------------------------------------- |
| `char[len]` | ArchiveName | NULL-terminated filename of the KIF archive |
| `uint32` | EntryCount | Number of entries in archive |
| `unsigned char` | IsEncrypted | `0x01` if archive is encrypted, `0x00` otherwise |
| `byte[4]` | FileKey | Blowfish key for decrypting entries (Only exists if IsEncrypted is `0x01`) |
| `0x00` | TableEnd | Signifies end of table |
### Archive Item Entry
| Data Type | Value | Description |
| ----------: | :------- | :------------------------------------ |
| `char[len]` | FileName | NULL-terminated deobfuscated filename |
| `uint32` | Offset | The offset to the entry's data |
| `uint32` | Length | The length of the entry's data |
## Notes
### Parser
- 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`
### Script
- `blend` argument specifies the alpha value that the image will be displayed at
- `cg 0 blend 255` will display a completely opaque CG while `cg 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 take `30` frames to fade the image from alpha `0` to the target alpha (e.g. `255` by default)
- Units are likely in frames at `60`fps (`0.0167s/frame`) regardless of the game's refresh rate setting
- An `rdraw` command will apply to all images within a script block (from a user input to the next `wait` command)
- `wait` command without arguments will block until any time-based command completes
- `wait` after a `rdraw 30` command will wait for the `30` frames taken to completely fade in the images before proceeding to the next command
- `wait` with arguments behaves differently from standalone `wait`
- `wait 60` will block for `60` frames before proceeding to the next command
- `wait 60` will not be aware of any time-based commands like `rdraw` and will not block until `rdraw` completes
- `wait` is sometimes used along with `wait 60` consecutively
- `cg 0 attr 1 (70+0) (80+0)`
- `cg 0 attr 2 (75+0) (85+0)`
- Assigns the `BaseX`, `BaseY` values of the specified image `cg 0` to the variables `#(75+0)` and `#(85+0)` respectively
## Special Thanks
- [Trigger](https://github.com/trigger-segfault) for creating such an [amazingly comprehensive knowledgebase](https://github.com/trigger-segfault/TriggersTools.CatSystem2/wiki) of the CS2 engine
- [asmodean](http://asmodean.reverse.net/pages/exkifint.html) for being a pioneer in reversing the CS2 engine
- [Dodder](http://www.doddlercon.com/main/) for [Hacking the Grisaia](http://www.doddlercon.com/main/?p=171) for localization
- [koestl](https://twitter.com/koestl) for his impeccable translations and contributions to localization