Guide to restoring Hidden Palace in Sonic 2 CENSOR Prototype

Discussion in 'Engineering & Reverse Engineering' started by Random Gaming, May 4, 2019.

  1. Random Gaming

    Random Gaming

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    This topic is a quick guide on how to fully restore Hidden Palace in the Sonic 2 CENSOR Prototype through having two savestates, an emulator, a Hex Editor and two Sonic 2 Prototypes

    Step 1) After downloading an emulator that can create genecyst savestates (*.gs*), a Hex editor, Sonic 2 Simon Wai Prototype and Sonic 2 CENSOR Prototype, create a savestate in the CENSOR Prototype in Emerald Hill Act 1.

    Step 2) Edit that savestate and change location 12288 from Hex Value 00 (EHZ Zone ID) to Hex Value 08 (HPZ Zone ID), then fire up the savestate and you'll see a glitchy background. From there go ahead and kill Sonic (in Act 1 always) and you'll spawn in Hidden Palace. Then just create another savestate while in Hidden Palace Zone.

    Step 3) Open Simon Wai Beta. While in the Title Screen press A+Start and you'll see a Level Select. Select Hidden Palace and when there, create another savestate. Now here comes the copying and pasting.

    Step 4) Start up your Hex Editor and open up both savestates there. Now using the (outdated but simple and useful for what we're doing) Guide, copy the 128x128 block mappings, the level layout, the 16x16 block mappings and all of the video ram from the Simon Wai Savestate and paste it to the CENSOR savestate. You may want to copy and paste Sonic's x and y position, due to the high chance of you spawning in the wall.

    Step 5) Load the CENSOR savestate into your emulator while running said Prototype and you'll be right into Hidden Palace with the final Sonic Sprites, all objects intact and the correct collision.

    NOTES: If you die in Hidden Palace you'll respawn back into the glitchy mess we started with. Also another thing to note is that trying this exact method in the final version of Sonic 2 will restore most graphics, but will not restore enemy data and if you have all seven Chaos Emeralds by jumping only once with fifty rings you will turn into Super Sonic (probably just due to some data location changes from the betas to the final).
    Leave your questions or suggestions in replies below.
     
  2. ICEknight

    ICEknight

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    ...Yeah, copying and pasting levels from one savestate to the other is a thing. Why is this special?
     
  3. Ravenfreak

    Ravenfreak

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    What year is this 1999? :v: I haven't seen anyone mess with savestate hacking, because I didn't join the community until 2008 and even then it would still be outdated. Plus I don't think you should have posted two topics in separate areas of the forums stating the same thing.
     
  4. Fred

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    This is perhaps a bit too harsh, because if I'm reading his post correctly, the CENSOR prototype still has the object code for the HPZ enemies, so you get the unique combination of final Sonic sprites + playable Hidden Palace, which we still haven't seen anywhere besides the magazines of the time.

    Having said that, though, this is the kind of scenario where a video would be worth a thousand words!
     
  5. Random Gaming

    Random Gaming

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    Well, there are people here who probably didn't know that. It also has varying results based on the version of the game and the level. For example Wood Zone to Sonic 3 CENSOR has the same collision except from the slopes which are pretty broken, such as Hidden Palace in the Final has major collision issues and a few minor graphical ones. Anyway I though it could be useful.

    So you're saying that I should make a video showing this method?
     
  6. Hez

    Hez

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    Good effort man. Don't let this get you down, but all this stuff has been known for a while. Id suggest searching around the hacking forum here before posting discoveries.

    Can someone trash this?
     
  7. Fred

    Fred

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    I'm saying a video would show off the interesting bits without forcing the casual observer to jump through so many hoops.

    I took the bait anyway, so here's a CENSOR proto savestate. I took the liberty of not copying ALL of the VRAM, so you start from the middle of title card (at which point which the level has loaded).


    Can someone please enforce the backseat moderating rule? Oh wait, shit. Never mind.
     
  8. Super Egg

    Super Egg

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    I already did this, except I actually added the level assets via hex editing and rudimentary assembly....

    http://forums.sonicretro.org/index.php?showtopic=38434&view=findpost&p=938471
     
  9. Random Gaming

    Random Gaming

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    Okay, I'll give the video a shot. Can you tell me where I can possibly post it on Sonic Retro, after posting it on YouTube?
     
  10. Laura

    Laura

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    It's curious the way people really want to trash threads on here.

    This is a good thread, not everyone here is a super hacker.
     
  11. Toasty

    Toasty

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  12. Super Egg

    Super Egg

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    I mean, the concept is neat I guess, but savestate hacking in 2019? We have all the assets of HPZ from the protos via disassemblies, and MainMemory's SonLVL can convert them to S2F's format. All that really needs to be done is to find the locations of where the level art and the level layout is pointed at , change them to somewhere after the end of the ROM, add them in using a tiny assembly file that has the data inc'd to the points you've assigned in the hex locations from earlier, and that's it. The collision, ring layouts, and object layouts are still intact.

    I will say however, if this is op's first dip into Sonic hacking, Congrats! I am impressed that you'd go into something so archaic, but if you're willing to start there and move up, I'm certain you will do great things in the future.
     
  13. Fred

    Fred

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    Sigh.

    I don't get it. What is this vitriol against savestate hacking? If all the data we need to patch back into the game is loaded to RAM anyway, and if it allows us to explore something unique about the CENSOR prototype, namely Hidden Palace Zone in its closest state to completion, before data started being removed from the cartridge, then how is distributing a modified savestate worse than an edited ROM which you still have to load into an emulator, and then edit the RAM anyway to change the current level because HPZ is not accessible from the level select?

    I swear to god, you guys seriously disappoint me sometimes!
     
  14. ICEknight

    ICEknight

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    Ok, maybe it sounded too harsh (sorry!) but my question was not rhetorical, I was actually wondering why this could be useful.
     
  15. Hez

    Hez

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    You weren't too harsh at all. This should, at minimum, be in the hacking forum. Granted, I'm not sure if trial members can see it or not. Whatever the case, it should be moved there at minimum.

    To my point...why are we allowing this shit? You could spend a bare minimum of 5 minutes googling and...HOLY SHIT, http://forums.sonicretro.org/index.php?showtopic=10872. WOW. http://www.romhacking.net/start/ HOLY SHIT!

    Or we can continue to feed the new people peanuts and they'll never learn? At least the Human Super Sonic topic was entertaining.

    EDIT: I should state right now I think the guide is a decently written guide. I don't want to discourage this guy from making them. I'm more disappointing in the older members.

    And Laura, what the fuck? There is literally a forum dedicated to this shit. Do you like to just see yourself post sometimes? You've been around long enough to know this. Am I taking crazy pills or something?
     
  16. Black Squirrel

    Black Squirrel

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    The CENSOR prototype is quite new so I guess it wouldn't be fair to expect it to be fully documented, but I didn't know this.


    There's so much of this sort of thing in these Sonic prototypes. Little facts that haven't been written down because someone decided it wasn't important.
     
  17. Overlord

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    I'll be honest - confusion on my part over whether or not this was actually something of note was the only reason I didn't trash this when I first saw the topic a few days ago - as noted, savestate hacking is nothing new in the slightest. It does seem as if something new is here though, so I'm just going to move it to the hacking subforum (where it should have been in the first place).
     
  18. Random Gaming

    Random Gaming

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    Since this isn't a rhetorical question, it is special because I was excited at the moment. But in all seriousness, it is kinda like temporary ROM Hacking, but a little bit limited. You can see in which versions of the game collision for certain removed levels has been kept. As an example I'll use three versions of Sonic 2: Simon Wai, CENSOR and Final. In CENSOR the collision for Hidden Palace has been kept the same as in Simon Wai, but with the tubes actually making you roll into them (probably engine work), while in the Final there is collision that makes you barely able to get through the level (the tubes still make you roll). Let's take another level as an example: in Wood Zone for Simon Wai collision is wacky, well CENSOR keeps that wacky collision, but makes it worse by making slopes use “blocky” collision, meaning that you can't just run over them and you have to jump. I hope this was helpful and changed your mind on savestate editing a bit.
     
  19. Clownacy

    Clownacy

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    ...So it's not special.
     
  20. Super Egg

    Super Egg

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    I'm just gonna go ahead and just discuss some of the Sonic 2 Censor stuff because this topic has gotten silly and some of y'all are acting like we hit a goldmine when in actuality, we haven't. I'll start back with Neo's post.

    I'm gonna tell you why it really doesn't matter in about 3 paragraphs further down. Might as well condense this post and answer all similar questions.

    If anyone was going to bother hacking the ROM (i.e like I did) to have the HPZ level art and layout data, they'd take the additional two minutes to find the location of the level select array and change the HPZ level entry from $FFFF, to $0800. It isn't rocket science.



    Ok, moving onto the meat and potatoes of this post. I'm gonna break down this post as nicely as I can to cover everything that needs to be addressed.

    The collisions for HPZ has been consistently been the same since the Nick Arcade proto. NA, Wai, Censor, and Beta 4 are exactly the same. The reasons the tube act differently is because they added in the spin objects (Obj85 iirc) that force the player to spin. Which on that note, that is the only object change since the NA proto, is the addition of the spin objects. From the looks of things, HPZ was just being used to test out the spin object, because nothing else has been changed.

    Since we are still on the subject, the ring and object layouts are still the exact same that we see in the Beta 4 build we have. The Censor proto doesn't have anything new to add to our knowledge of HPZ. Beta 4 also had the HPZ badnik code and art intact.

    Gonna stop you there. The collision maps used in Wood Zone is just MTZ's. Wood Zone was already good and dead by the Censor build.


    The tl;dr: The Censor Prototype is very much a bust, and if you were expecting some kind of big find, it's pretty much Beta 4, except with CPZ's diagonal loops. Sorry to suck all the fun outta this.