Jet Grind Radio Custom Graffiti
Posted: Sat Mar 22, 2025 10:15 am
After some research and thorough experimenting I managed to create custom Jet Grind Radio graffiti saves. It's basically a jpeg with a 1-bit transparency channel tacked on. 
Here's my notes so far:
Here's my notes so far:Code: Select all
640 bytes - VMS Header and VMU Icon
4 bytes - size of title
n bytes - title
4 bytes - size of description
n bytes - description
4 bytes - size of e-mail (optional)
n bytes - e-mail (optional. can be blanked out alongside the size with four empty bytes)
4 bytes - size of transparency data (00 xx xx 00) 0800 = small, 1000 = large, 2000 = extra large
2048/4096/8192 bytes (or $0800, $1000, and $2000) - Transparency data. (0 for transparent, 1 for opaque, need to reverse bits of each byte.)
4 bytes - size of unknown bytes, copyright, and jpeg data as a short. Theoretical max jpeg size would be ~63.99KB
6 bytes - unknown, possibly a portion of the copyright?
36 bytes - SEGA copyright
n bytes - JPEG data (headerless. can't be progressive)- Display of Newgrounds Graffiti Pack
- Small Custom Graffiti Example
- Large Custom Graffiti Example
- Extra Large Custom Graffiti Example
if I knew how to make programs I'd try to make a converter for it if I could.