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Sonic 2 VS (Coming Soon)

Discussion in 'Engineering & Reverse Engineering' started by E-122-Psi, Aug 12, 2020.

  1. Black Squirrel

    Black Squirrel

    no reverse gear Wiki Sysop
    Northumberland, UK
    steamboat wiki
    That special stage is one of the best things I've seen on this board.
  2. That special stage usurps Chaotix' native one as the dopest emerald-hunting tunnel in existence. Did my eyes and ears decieve me, or is there a mild delay prior to regaining control of your character upon exiting the special stage? If so, I fullheartedly approve of the move as it should ensure that everyone resumes the stage on equal footing. That countdown timer is a wonderful thing.

    Definitely keeping my eye on this!
    Last edited: Jun 20, 2021
  3. doc eggfan

    doc eggfan

    Are you pondering what I'm pondering? Wiki Sysop
    GreatMegaLD, GreatSC3k, Great SG1k
    That special stage is so impressive that I... I don't even understand what I'm seeing. It seems way too smooth. Is it "simply" the frame rate that's been increased in the special stage, or is it using some fancy colour palette rotations like in the SEGA splash screen intro for Sonic 3D, or was it just reworked from the ground up?
    Last edited: Jun 21, 2021
  4. Honestly, if there is any singular hack I hope we see the source code of someday, it’s this one. I wonder how much of the game’s code had to be refactored for 2P mode… and that’s only including the main stages!

    Also the 2P mode compressor tool would be cool
  5. McAleeCh


    This looks amazing - would love to know how exactly you've done those Special Stages, as they're noticeably higher-resolution than the originals and smooth as butter animation-wise! Incredible stuff - looking forward to seeing more as development progresses. = )
  6. Black Squirrel

    Black Squirrel

    no reverse gear Wiki Sysop
    Northumberland, UK
    steamboat wiki
    It looks like they've added more frames of animation, though whether that's done by loading in more tiles or by doing something clever with palettes... I couldn't even begin to guess.

    Scary thing is this looks better than the Taxman version and that's using real polygons. I suppose you could get nitpicky about the background not rotating super smoothly but... it's it's rotation on the Mega Drive. It's just a shame YouTube compresses the crap out of 240p video.

    Might be better to have the palette change to a new colour than "Special Stage: Night version" though. Maybe pick a random (pretty) one and have the palette interpolate - that would be impressive.
  7. nineko


    I am the Holy Cat Tech Member
    How is that even possible, that is all I have to say.
  8. Overlord


    Now playable in Smash Bros Ultimate Moderator
    Long-term happiness
    Once again, knocking it out of the park. Utterly staggering. I'd never have thought you could get special stages that close to the Taxman version on the actual MD!
  9. MarkeyJester


    Original, No substitute Resident Jester
    Oh it's more than a frame increase!

    When I was writing interprite, I wanted it to handle interpolating POV frames too, so I took the Sonic 2 special stage as an example and manually interpolated the straight path frames by hand, both by resolution and frame rate at x2 the amount. What's interesting is that there's jarring problem with the original that you couldn't have noticed because of how poor the frame-rate is, and interpolating it showed something rather nasty.

    [​IMG] [​IMG]

    Left is the original, right is the one I did by hand, carefully, with immense labour.

    As you can see, even though it's smoother, the orbs jitter left and right, and the arrows and lines don't come towards you in a logarithmic fashion correctly... It's almost as if the original wasn't pre-rendered and was done by hand (which, don't get me wrong, is still impressive if so despite being not accurate to three dimensional space, but I digress), in order to get a smooth frame rate and so on, one would need to interpolate the original 4 frames by an extra x4 to x8 times, ...and interpolate the resolution, ...and FIX the logarithmic inconsistencies... Given E-122-Psi to be fairly good at smooth sprite animations, he gave it a try doing one frame by hand, and while it looks fairly good, it was just taking way too long...

    So we prerendered the frames ourselves by software:



    It's effectively a special type of FMV player... sorta... it runs at 60fps, unfortunately, there isn't enough time to do the sprites and BG, so it had to be reduced to 30fps, one frame rendering the FG another frame dealing with the sprites, engine, BG, etc.

    It's funny you should mention palette cycling though, that was one idea we pondered, but after doing the calculations and testing, it looked to me it was going to require so many colour slots the Mega Drive did not have, not even for the original, let alone our version... It was written from ground up, everything, nothing of the original survived, we actually broke the original by accident (by we I mean I) and couldn't be bothered to keep fixing it, I still blame the disassembly and the way it sets up the "phase" RAM sections though d= Writing it from scratch did give us one advantage, we used chunk/block RAM for the special stage variables, and that preserved EVERYTHING in the level, the objects, the camera, remember states, you name it, so we accidentally created an internal savestate if you will, allowing you to return back to a level in 100% the way you left it.
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  10. Sonic Hachelle-Bee

    Sonic Hachelle-Bee

    Taking a Sand Shower Tech Member
    Lyon, France
    Sonic 2 Long Version
    This is incredible. That is certainly a hell of a lot of work. Congratulations!

    This also makes me sad. I worked hard lately on the Special Stage trying to do something similar. And by seeing your results, I must admit that I failed. You probably redesigned everything to have such an amazing result. There is no way this can work with the original Special Stage engine, it is far too slow to handle that "Blast Processing".

    I am very curious how this works technically, especially the full 256x224 resolution instead of 128x112, the foreground display at 60 fps (or at least 30 fps? I can't tell), and the smooth background rotation. Maybe everything is uncompressed for fast processing, eating a lot of ROM space? VRAM memory extension? This sounds too easy and raises other technical questions. I am sure this is way more complicated than that :)

    Hats off to your team.
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  11. MarkeyJester


    Original, No substitute Resident Jester
    Don't abandon your version!

    I have taken notice of yours, and I think it's still cool! Given it runs on the original engine and so on, I really would love for you to continue it, at least to prove what could be done with the original special stage engine at least!
  12. Brainulator


    Regular garden-variety member Member
    Honestly, in the Sonic 2 VS video, I was amused when I saw the speed-up power-up... and then immediately gleamed upon seeing the 2013-esque corkscrews. Nice work.

    I am curious what the plan is for Special Stages in this context is, though. It seems like a pacebreaker to me and perhaps an unwanted intrusion when one player activates the starpost without the other's consent (though at least everything is preserved).

    There are several other things I'd like to ask, but I'm not sure if they're appropriate to ask at this time.
  13. Beamer the Meep

    Beamer the Meep

    Better than Sonic Genesis... Member
    Like everyone else here, I'm pretty much floored at how smooth the special stages are. Given the amount of interest, maybe a video discussing how you guys managed to pull it off would be worthwhile, after the contest of course.

    Honestly, what's also impressive to me is how you managed to make Chemical Plant work in 2 player mode. Will the rest of the Sonic 2 stages not in the original 2-player mode be playable?
  14. Flygon


    The complete and utter insanity.

  15. E-122-Psi


    That is the intent.

    We have Hill Top and Chemical Plant more or less in working order besides a couple bugs. Aquatic Ruin and Oil Ocean are more problematic, but they're mostly graphical issues, you can race in them so long as you don't mind them being ugly. :P Metropolis is the biggest issue right now, since it's vertical wrapping causes object loading issues.
  16. DeltaW


    Originally a Wooloo Member
    I said it on YouTube but I'll say here.

    I was quite happy when I saw E-112-Psi shared some images here not too long ago. But looking at your video, I was delighted to see I can play Sonic with a friend, again, through more zones than the usual 3 plus special stage. In general, I really like the presentation overall, I see every second of that video come together to form the word "perfection". Along with the smoothness and expansion of the special stages and the ability to change character palettes, I'm seeing boundaries smashed wonderfully.

    One thing to suggest is much like Sonic 2, how there were unique songs for the 2 player mode such as Emerald Hill, Mystic Cave and Casino Night, will there be unique songs specifically designed for that specific mode? If so, that would be pretty cool and a nice change to the hack. =D

    Overall, I'm seeing a lot of potential here and I wish you and the team luck in making this a demo or even a full release.
  17. Zeta_Null


    Nobody seems to have brought it up but it seems like knux was accidentally revealed in the trailer lol
    He does work, by the way, so here's a screenshot of a knuckles & knuckles race.

    Attached Files:

  18. Blastfrog


    See ya starside. Member
    MarkeyJester, you are a god among men. I am absolutely stunned by everything going on in that new special stage, excellent work!
  19. Prototype


    I was sitting there, thinking "neat, I wonder how they ironed out all the kinks with splitscreen", and then without warning you just throw us into that absolute madlad special stage. Turning it into a competitive race is GENIUS. The speed boosts and rotation and hills...

    I don't feel like my words can express what a fantastic job you all have done so far.

    Would you settle for a "Way Past Cool"?
  20. Lostgame


    producer/turnablist. homebrew dev. cosplayer. Oldbie
    Toronto, ON
    The O.I.C.
    That special stage is something. Great fucking work, guys. <3