<!--
.. File: README.md
.. Location: https://bgstack15.ddns.net/cgit/srb_lib
.. Author: bgstack15
.. SPDX-License-Identifier: GPL-3.0-only
.. Startdate: 2024-03-20-4 10:14
.. Title: Readme for savegame editor for Snoopy vs. the Red Baron
.. Project: srb_lib
.. Purpose: Read it.
.. Usage: Read it.
.. Reference: See heading References
.. Improve:
.. Documentation: Read it.
-->

# README for Savegame Editor for Snoopy vs. the Red Baron
Modify an existing savegame file for the PC game [Snoopy vs. the Red Baron (2006)](https://en.wikipedia.org/wiki/Snoopy_vs._the_Red_Baron_(video_game).

# tl;dr

    ./srb.py --profile 1 --unlock-everything --buy-everything ~/"Documents/Snoopy vs. the Red Baron/Profile 1/Profile 1.sav"

## Upstream
This project's upstream is at <https://bgstack15.ddns.net/cgit/srb_lib/>.

## Alternatives
None found.

## Reason for existence
The author was unable to find any trainer or savegame editor for this game, and I wanted to be able to reset certain elements or cheat and give myself everything. Mostly I wanted "Octo-gun" and I was concerned I wasn't good enough to beat every level (mostly boss levels) with rank General. I did actually beat the game with 100% completion before I finished this tool.

## Using
Most capabilities have "set" and "get" parameters. Some have "set" and "add/remove" parameters. To see a full list of commands, run `./srb.py --help`.

Some common examples.

    ./srb.py --profile 1 --set-name "newname" --file "Profile 1.sav"
    ./srb.py --profile 1 --set-money 10000 --file "Profile 1.sav"
    ./srb.py --profile 1 --set-level 5,done --file "Profile 1.sav"
    ./srb.py --profile 1 --set-health 4 --file "Profile 1.sav"

Note that `--set-level 5,done` operates three separate parameters that could be done individually:

    --set-level-status 5,general
    --set-level-balloons 5,all
    --set-level-letters 5,all

Individual letter/balloon control is not implemented at this time.

## Dependencies
Just python3.

## Building
N/A

## Design notes
The checksum used is this crc32:

    crc width=32 poly=0x4c11db7 init=0x0 xorout=0x235b4b9c refin=false refout=false out_endian=little

Which I only learned through the reverse-engineering efforts of <https://github.com/8051Enthusiast/delsum>.

Before I learned this, none of this savegame editing was possible.

The binary contents are stored in little-endian, which makes visual inspection of the file in a hexeditor slower.

## References

1. <https://bgstack15.ddns.net/blog/posts/2024/03/22/initial-research-for-hacking-savegame-files-for-snoopy-vs-the-red-baron/>
2. <https://bgstack15.ddns.net/blog/posts/2024/03/26/the-checksum-for-the-savegame-file-for-snoopy-vs-the-red-baron>
3. <https://github.com/8051Enthusiast/delsum>
4. <https://gist.github.com/Lauszus/6c787a3bc26fea6e842dfb8296ebd630>
5. <https://stackoverflow.com/questions/46109815/reversing-the-byte-order-of-a-string-containing-hexadecimal-characters>
6. [Walkthrough for Snoopy vs. the Red Baron](https://gamefaqs.gamespot.com/pc/930591-snoopy-vs-the-red-baron/faqs/46161)