128x128 Chunks System - RetroKoH/S1Fixed GitHub Wiki

(Credit: MarkeyJester, Kramlat/kram1024, Clownacy, RetroKoH)
Source: GitHub Repo
Commit: 3f2082a

S1Fixed uses the Sonic One: Two-Eight disassembly as a base. This means that level metatiles (chunks) are 128x128 pixels in size, as opposed to 256x256 pixels like in the original Sonic 1. What does this mean however? Put simply, here are the key differences:

• Chunks are now 1/4 their original size, allowing for greater flexibility in level design.
• As there are far smaller chunks (despite levels retaining their set pieces and layouts), this means that there are a far greater number of chunks to make use of.
• Loops now utilize a collision path swapper object (Obj03) that alters the collision "plane" that Sonic is standing on.
• As a result of the above note, every level has two sets of collision data instead of one, though this only affects Green Hill and Star Light Zone (With greater modification, other zones can take advantage of this as well).

Code changes can be found by searching for ; MJ in the .asm files.

More info can be found here.