Sega Saturn interesting finds

Discussion in 'Engineering & Reverse Engineering' started by Sonicstudium, Jan 19, 2013.

  1. Sonicstudium

    Sonicstudium

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    So I was looking to rip some FMV sequences from Rayman on Sega Saturn a few days ago but couldn't find the disk. I didn't know whether my disk ripping program would even run Saturn games yet, so I decided to run whatever game I still had in my Sega Saturn, which happened to be Sonic Jam. Needless to say, the program worked like a charm and ripped the files on the disk into their own folder. I later found the CD case that had Rayman and my other Saturn Sonic games in it and got to ripping those as well.

    What I found was quite strange to say the least.

    In Sonic Jam's files, I found that I could view certain files correctly in Tile Layer Pro and assemble them into perfect sprites. These were mostly the sprites for Sonic and Co, along with some special stage artwork, and the Pause Menu graphics. Some files also contained a few compressed looking files, but they were somewhat viewable. Despite having strange file extensions, they can either be opened in TLP and formatted to Genesis, or they can be re-named as BIN files and opened in TLP normally.

    As for Sonic 3D, I found some interesting pictures that I have no way of opening. Although I cannot open them, I have a feeling that at least two of them are unused files from the PC version that are also unused here. They are the two pictures of Sonic with Knuckles and Miles that were theorized to be connected to the Special Stage on the Wiki. Another interesting thing is that the special graphics that were added for this version of the game are in their own folder that's separate from their respective level folder. (Things like the new bridges and the weather effects.)

    And for Sonic R, all I was able to uncover was a strange naming system for all the levels. They are NOT called what they are normally called in game. (Resort Island is called BEACH for instance.) Rayman used a similar naming system for its levels, though it was discovered by the public as early on as the release of Rayman Designer, which called the levels by their internal filings rather than established names in universe.

    Now for proof, all I can post are some pictures at this time. I don't want to put up the files unless I'm told otherwise that I won't be banned for doing so, however I will post a text file showing my research of Sonic Jam so that you can get somewhat of a look as to what I've found.

    A rip of Sonic's Sonic 1 art from Sonic Jam, which is located in a file called "DATA.SN1". All that's on here is the graphics for Sonic. They are also unassembled, though Sonic seems to have all of his unused frames intact.
    Also located here are the dust effects for when he skids or spindashes.
    [​IMG]

    Another screenshot from TLP showing the Sonic 1 sprite being assembled in the tile viewer.
    [​IMG]

    A screenshot of TLP showing Sonic Jam's in-game pause menu. Strangely, certain parts are either compressed or omitted from the pause menu graphics, such as the top half of the CONTINUE text.
    [​IMG]


    A screenshot showing Sonic R's strange internal naming. I'm unsure if the PC version names them the same way, so if anyone could tell me, that'd be great.
    [​IMG]

    As for the Text file, it's still being updated as I check the files in my HEX editor. If you still want to see the incomplete file, you can find that here:
    Sonic Jam Documentation v0.1

    I do apologize if someone else has also found this and posted it before me, I couldn't find any topics pertaining to this using the Search feature. I hope this allows others to learn more about how Sonic Jam works, and (hopefully) to spark more interest in the Sega Saturn.
     
  2. dsrb

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    Well, Jam runs ported versions of the MD games, so it's perfectly predictable that it would store their data, and trivial things such as the pause overlay, in an almost-compatible format.

    As for Sonic R and the “weird” names: firstly, they're not weird at all, as they make sense in the context of the levels’ environments; and secondly, you can't have filenames longer than 8.3 format in ISO-standardised data CDs such as those by the Saturn, so they couldn't possible be called their ‘normal’ names anyway.
     
  3. Sonicstudium

    Sonicstudium

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    Well the reason I noted the viewable Sonic graphics is that for the longest time I've seen people saying that they couldn't extract the graphics from Sonic Jam because it's not an emulation of the Genesis games, and that they can't extract them.

    As for Sonic R, I understand as to why they named the files like that, I just found it a little strange that they're referred to as such.

    Now please note, I'm still researching the files I have right now, so I haven't posted everything that I COULD post. I'm just trying to get this started so that I can post everything as I find it. Heck, I'm still looking through Jam's files through hex editing and TLP.

    I've seen a topic by Master Emerald that asked for a rip of the Sonic 3D Blast Saturn ISO, which I do have. I may have to tell him that I've got a rip.

    I wonder if the compressed graphics that I can't see in TLP use a similar compression to any of the formats that have been established.
     
  4. dsrb

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    Cool, not meaning to discourage you, as more attention to the Saturn is something I really like to see! :) Good luck with it.
     
  5. Sonicstudium

    Sonicstudium

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    I'm currently working on ripping the textures from Sonic World. Unfortunately the only thing I have to rip with is Satourne, so it might take a while.

    As it is, I think it would be a fun little project to attempt to find out how Sonic Jam's textures are stored, if a successful attempt hasn't been made before.
     
  6. Friend of Sonic

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    Which brings up an interesting point IMO: Has Sonic Jam ever been fully explored? There might be something interesting for Sonic World that was unused.
     
  7. Yeah, ripping the entire model of Sonic World would be nice, since there's an unused part near the waterfall!
     
  8. ICEknight

    ICEknight

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    After seeing those graphics in the same old format I need to ask, has anybody ever tried porting the Sonic Jam versions back to the Mega Drive?

    I mean, proper ports with the actual code and data from the Saturn disc and not just approximations based on what you can see while playing.
     
  9. InvisibleUp

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    The PC directory looks like

    [​IMG]

    The one straight off the CD looks nearly identical. (In fact the installation process is probably a straight-up copy/paste I believe.) Strange how they completely changed the layout of it disc. It seems unusually pointless, especially considering they were too lazy to put music on half the discs.
     
  10. Scarred Sun

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    That happened years ago.
     
  11. dsrb

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    LOst's port had the data, or at least most of it, but not the code or art:
     
  12. ICEknight

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    That hack seems a bit incomplete (was the coding for the skidding dust and the final boss also in Saturn format?), but I didn't just mean the Easy mode, anyway... I remember Normal mode having small differences as well, like solidity in those rising platform/walls in Green Hill. I wonder if that kind of stuff can be ported back as well.

    Those small changes might be worth looking into, by the way, if only for curiosity's sake. =|
     
  13. Eric Wright

    Eric Wright

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    "Normal" mode had additional item boxes and rings in certain places, if I recall... All I remember was playing normal mode for a couple levels back when I first got Sonic Jam, and I was put-off by whatever they changed compared to the original version, so I avoided Normal mode from that point forward. I think it was just still easier than Original or something like that
     
  14. ICEknight

    ICEknight

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    Oh, I had completely forgotten that "Normal" and "Original" were two different modes... So that makes two versions that haven't been attempted at "back porting".
     
  15. Black Squirrel

    Black Squirrel

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    There's actually quite a few, because only the level layout (I think) of Sonic 1 easy mode has been brought over.

    There's effectively... eighteen(?) different games, as each game comes in three different varieties (and even the "original" modes come equipped with bug fixes IIRC). There are also time attack options though I'm not sure if they changed anything in-game.


    This is why that old hack was always a bit disappointing to me - it doesn't represent the true extent of Sonic Jam's changes (and I'm not sure back-porting code to the Mega Drive ever could - sound effects are slightly different and there are subtle pauses in music as the disc loads).


    and of course all the PAL versions run at full speed IIRC, so differences between variants of Sonic Jam no doubt
     
  16. dsrb

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    It's only the timing of the music that the PAL version of Jam has optimised to run at full speed regardless of region (which is only a new feature for the first game, as the PAL MD versions of the sequels did the same thing already); the games are still bordered and slower when played on PAL systems.

    Sonic World and menus are fully PAL-optimised, however. So, playing a PAL copy of Jam on a 60 Hz Saturn is fine for the ported games, but too fast and clipped vertically for the other parts.
     
  17. Sonicstudium

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    On the note of this, I think I've got a reasonable explanation as to why there's that sidewalk near the waterfall. First off, the way the game textures the terrain in game is really weird. It seems to either use a heightmap to generate the terrain and then overlay one big texture on top of it, or it uses a general model and then places one big texture on top of it. This is so that they don't have to render shadows underneath every stationary object. (Like the bridges and buildings and such.)
    The textures of the walls and other objects would go on top of this big texture so that it would look like it was supposed to.

    I say this because I found pieces that contain a path and sidewalks in the VDP2 background viewer of Satourne. They were stored two at a time in 512X512 pieces that are placed in vertical rows, though I'm only able to get part of the second piece on each set at this time. (My monitor isn't just big enough to display the whole thing, even with the task bar hidden.) If anything, I would say that the Sidewalk tile located near the waterfall is either a misplaced tile or a misplaced texture, because the tops of the outer walls sometimes use textures to simulate grass hanging down.

    Here's what I've found, though it's incomplete due to me being unable to see the entire 512X1024 section:





    (Disregard the Sonic X-Treme texture, I wanted to test the plugin on another game and I forgot to delete that part.)
    [​IMG]
     
  18. Meat Miracle

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    That panel behind the waterfall is simple. The Saturn has a dedicated engine to displaying backgrounds (VDP2), which includes two scrolling backgrounds, two overlays, a rotating background (this is a fully 3d part), some other basic background screens, transluency between them and the normal sprites, etc. This is ontop of the sprite engine (VDP1) which is the one loading polygons that compose everything but the HUD and the ground (and maybe the extra menus and hints and crap you can bring up, haven't checked those).

    The ground in Sonic World uses that thing, and displays a rotating background. It reads the graphics from it's own memory, and it could rotate either bitmaps or compose one out of tiles (patterns) and so on. Sonic World uses patterns.

    That extra hidden ground part is just a junk tile used elsewhere that got generated there out of accident.
     
  19. Tiddles

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    On Easy/Normal/Original: you might or might not recall that Sonic 3 Complete has the data for these modes too, and you can select them in the options menu. I've never even glanced at porting the code, but I've recreated all the features I know about in those modes (particularly bosses having a lower hitcount and act skipping in Easy mode, and special stages never speeding up in Easy and Normal modes) and I'd certainly implement any anyone else can point me to. From this perspective, it certainly would help to have a thorough analysis of the Saturn code.

    However, based on what I've seen in Jam S3&K, porting the code back from that really wouldn't be worthwhile - I know it's often been said that the Jam versions fix some bugs, but it seems to me that they cause more problems than they solve. Among the ones I remember off the top of my head:

    • All the rings disappear in the glowing spheres bonus stage. (This one could be an emulation issue - I don't have any hardware to check it.)
    • You can get stuck at the end of the game in easy mode by beating the final emerald-holding Robotnik too soon. (This could have happened with the end of FBZ too, and if you've ever wondered why FBZ Robotnik behaves differently when killed in Jam, this is almost certainly the reason.)
    • You usually get a dud object sticking around after the MTZ-style SSZ boss in Easy mode.
    • Debug super monitors create a glitched Super Sonic.
    OK, admittedly half of those relate specifically to the reduction of boss hit counts in easy mode, but that was clearly done in such a hamfisted and poorly tested manner that I struggle to believe there are many more worthwhile improvements hanging around, beyond what people here have fixed for themselves - but I'd be happy to be proved wrong!

    Even porting the object layouts doesn't always work all that well, because the Jam versions don't seem to implement the same VDP sprite limits (why would they?) so some of the layouts spam objects all over the place that cause flickering on the MD. The worst case of this I know of is at the bottom of Icecap 2, towards the end, on Easy/Normal, where the floor is filled in with a load of sprite-based floor pieces.
     
  20. ICEknight

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    I personally wouldn't mind about that kind of stuff, as long as proper, clean, direct ports could be made, with no extra menus or anything that wasn't present in those versions, besides the code conversions needed for the Saturn-specific functions (spindash in Sonic 1).

    Being able to check them out and seeing all the Mega Drive limitations that weren't taken into account would be kind of interesting, actually.