3 ms·

That brings back memories! I actually reverse-engineered that exact sprite compression (at least the G/S variant) back in 2001, when I was involved in the early

That brings back memories! I actually reverse-engineered that exact sprite compression (at least the G/S variant) back in 2001, when I was involved in the early ROM hacking community [1]. I stared at disassembled Z80 machine code for many, many hours to figure out and document the various quirks. I wrote a decompression program in (terrible, self-taught) QBasic, the only programming environment I had access to / knowledge of back then. [1] https://www.romhacking.net/utilities/59/ https://www.romhacking.net/utilities/59/

kemenaran 7y ago
Oh, nice! The compression algorithm is said to have been written by Satoru Iwata himself, giving a hand to the overloaded GameFreak team when the development of Pokémon G/S was hitting size limits pretty badly [1]. There is a readable version of the decompression routines in the Pokémon G/S disassembly repo [2]. As the code was originally written in assembly, it is not decompiled–only re-documented. Which means the code we read is the actual code Iwata wrote it 20 years ago. I really like seeing the traces of actual human beings in a disassembly. Noticing different coding styles; seeing where routines were written, then patched over later… We read code, but we see people. [1] https://retrocomputing.stackexchange.com/questions/11476/how-did-satoru-iwata-compress-pokemon-gs-to-fit-two-regions-on-a-single-cartridg https://retrocomputing.stackexchange.com/questions/11476/how... [2] https://github.com/pret/pokered/blob/10289bf/home/pic.asm https://github.com/pret/pokered/blob/10289bf/home/pic.asm