Sonic and Sega Retro Message Board: Sonic 3 & Knuckles undocumented glitch - Sonic and Sega Retro Message Board

Jump to content

Hey there, Guest!  (Log In · Register) Help
  • 2 Pages +
  • 1
  • 2
    Locked
    Locked Forum

Sonic 3 & Knuckles undocumented glitch

#16 User is offline Tiddles 

Posted 31 July 2014 - 01:31 AM

  • Diamond Dust
  • Posts: 452
  • Joined: 25-December 09
  • Gender:Male
  • Location:Nottingham, England
  • Project:Get in an accident and wake up in 1973
  • Wiki edits:31
You only need to do FFAF; it's treated as a word, and 0001 is the normal value for S&K being attached.

It doesn't have anything to do with the Sonic 3 levels being involved or not - vanishingly close to all of the code is running from S&K even in those levels, just some data (graphics, chunk layout) etc. comes from Sonic 3. The easiest place I found to do this was Mushroom Hill, which will still just as happily reset you into S&K. The glitch even works in genuine S&K alone if you enable debug using PAR codes or other methods, minus the final reset into S&K being an interesting event. All it is is RAM corruption of the RAM addresses you mention, and it's entirely an S&K bug (though the same mistaken code probably exists in S3, it will never be called in S3&K). Crashes that don't corrupt RAM will not cause this.

And though it is likely an overflow, there is something peculiar about this situation, because it is guarded against in most object spawning scenarios. Skipping the Icecap 1 boss and keeping the snowflakes active will leak object RAM until the game becomes unplayable, but this corruption and crash won't happen; nor will simply spawning too many monitors to begin with. So they did think program for the object limit... just something here seems to sneak around it.

#17 User is offline Uberham 

Posted 31 July 2014 - 08:30 PM

  • King Of Oblivion
  • Posts: 1036
  • Joined: 23-February 08
  • Gender:Male
  • Location:Sheffield England
Could it be that coupled with the art change into super/hyper sonic? like the change forces the loading of new art, so it overflows from there?

#18 User is offline Tiddles 

Posted 01 August 2014 - 04:18 AM

  • Diamond Dust
  • Posts: 452
  • Joined: 25-December 09
  • Gender:Male
  • Location:Nottingham, England
  • Project:Get in an accident and wake up in 1973
  • Wiki edits:31
The relevant Sonic art is directly transferred from ROM every frame anyway, and the offset doesn't actually change for Super so they can share similar poses. The Super/Hyper stars do get loaded into their own object slot but their art is also dynamic (IIRC). So I'd be surprised if it's directly related to that, personally.

#19 User is offline muteKi 

Posted 01 August 2014 - 10:40 PM

  • Fuck it
  • Posts: 7427
  • Joined: 03-March 05
  • Gender:Male
  • Wiki edits:91
I was going to ask if it was because it had to spawn the broken-monitor object on destruction -- but then we'd expect this out of running through a series of badniks since they spawn an animal and a point total.

EDIT: oh right those despawn as soon as they go offscreen unlike the broken monitor

EDIT2: also seems to be REALLY hard if not impossible to trigger with other monitors besides the S one, so I bet the checking is related to a race condition with loading the super state
This post has been edited by muteKi: 01 August 2014 - 11:07 PM

  • 2 Pages +
  • 1
  • 2
    Locked
    Locked Forum

1 User(s) are reading this topic
0 members, 1 guests, 0 anonymous users