Sonic 3 (Nov 3, 1993 prototype) - Technical Analysis & Research thread

JoseTB · Nov 18, 2019

The main thread is unfortunately inundated with fan theory discussion, so much so that the actual technical research is getting buried, so I feel like a separate thread is in order.

Since I did torture myself with going through the 20 odd pages of that thread, I'm going to take the liberty to quote some of the noteworthy posts there that would fit here. If anyone is uncomfortable with me doing this, please let me know and I'll proceed to delete the post(s).

Sonic Retro: https://info.sonicretro.org/Sonic_the_Hedgehog_3_(prototype;_1993-11-03)/Comparisons
Hiddenpalace.org: https://hiddenpalace.org/Sonic_the_Hedgehog_3_(Nov_3,_1993_prototype)
The Cutting Room Floor: https://tcrf.net/Proto:Sonic_the_Hedgehog_3

JoseTB · Nov 18, 2019

evilhamwizard said:

Taxman and Stealth have a lot of splainin to do!

Also, the ROM has some left over shit from earlier builds. I could go on, and on, and on but I didn't want to overload the page on the wiki. Check out the stuff in the offsets I mentioned, it's a real treat.

Lava Reef Zone's Kosinski archives are present in their entirety, that's how we were able to restore it. The level layouts for Act 1 and 2 still exist, but we couldn't figure out what was wrong with Act 2 as far as pairing the graphics with it. Lava Reef's remnants come from a time when the 2P zones were just being implemented. You can actually see older versions of those zones still in the ROM, some of which are using tiles that look like collision chunks instead.

In another leftover chunk, the level palette table is present in its ENTIRETY. So the palettes for all the zones worked on before the split still exists.

Merry Christmas!
Click to expand...

JoseTB · Nov 18, 2019

Ralakimus said:

I just checked the code for the "drop dash".

It's not a bug. It's deliberately put in.

Code (Text):

ROM:0000B61C Sonic_Jump: ; CODE XREF: ROM:0000AE84p

ROM:0000B61C move.b ($FFF603).w,d0

ROM:0000B620 andi.b #$70,d0 ; 'p'

ROM:0000B624 beq.w locret_B6F0

ROM:0000B628 move.b ($FFF602).w,d0

ROM:0000B62C andi.b #$D,d0

ROM:0000B630 cmpi.b #1,d0

ROM:0000B634 bne.s loc_B63C

ROM:0000B636 move.w #$FFFF,($FFFE5A).w

ROM:0000B63C

ROM:0000B63C loc_B63C: ; CODE XREF: Sonic_Jump+18j

in Sonic_ResetOnFloor

Code (Text):

ROM:0000BFF2 loc_BFF2: ; CODE XREF: Sonic_ResetOnFloor+74j

ROM:0000BFF2 tst.w ($FFFE5A).w

ROM:0000BFF6 beq.s locret_C00E

ROM:0000BFF8 bmi.s loc_C010

ROM:0000BFFA asr $1C(a0)

ROM:0000BFFE asr $18(a0)

ROM:0000C002 move.w #0,$1A(a0)

ROM:0000C008 move.w #0,($FFFE5A).w

ROM:0000C00E

ROM:0000C00E locret_C00E: ; CODE XREF: Sonic_ResetOnFloor+80j

ROM:0000C00E rts

ROM:0000C010 ; ---------------------------------------------------------------------------

ROM:0000C010

ROM:0000C010 loc_C010: ; CODE XREF: Sonic_ResetOnFloor+82j

ROM:0000C010 move.w #0,$1A(a0)

ROM:0000C016 move.w #0,($FFFE5A).w

ROM:0000C01C bsr.w sub_ACEC

ROM:0000C020 move.b #9,$20(a0)

ROM:0000C026 move.w #$3C,d0 ; '<'

ROM:0000C02A jsr (PlaySound).l

ROM:0000C030 move.b #1,$3D(a0)

ROM:0000C036 move.w #0,$3E(a0)

ROM:0000C03C rts

Basically, if you are holding up, but not left or right as soon as you jump, it sets a flag to -1. Later in Sonic_ResetOnFloor, it checks that flag. For when it's negative, it goes to loc_C010, where it sets Sonic up to spindash, in which if you are not holding down, it will act as a "drop dash" and boost Sonic as he touches the floor. If you do start holding down after doing the Up + Jump thing, Sonic will start spindashing when he touches the floor.

Interestingly enough, if said flag is a nonzero positive number, it seems to just halve Sonic's X speed.
Click to expand...

JoseTB · Nov 18, 2019

Rika Chou said:

Here's the new Sonic sprites:

Click to expand...

JoseTB · Nov 18, 2019

Rika Chou said:

Part of Knuckles' sprites, the rest look final:

Click to expand...

JoseTB · Nov 18, 2019

Rika Chou said:

Clean shot of the HCZ act 1 BG: EDIT: Updated to include the full BG.

While I think the final BG is much better, I really like the colors on this.

Click to expand...

Devon · Nov 18, 2019

Dammit I was gonna repost my drop dash thingy code here.

Here's my findings regarding the title screen at least:

Ralakimus said:

Fun fact, the code for handling the frame reloading for the title screen is in the prototype.

Code (Text):

ROM:000035EA

ROM:000035EA ; =============== S U B R O U T I N E =======================================

ROM:000035EA

ROM:000035EA

ROM:000035EA Iterate_TitleSonicFrame: ; CODE XREF: ROM:000033AEp

ROM:000035EA cmpi.b #1,($FFFFBD).w

ROM:000035F0 bne.s locret_3606

ROM:000035F2 move.w ($FFFFBE).w,d0

ROM:000035F6 move.b SonicFrameIndex(pc,d0.w),d0

ROM:000035FA ext.w d0

ROM:000035FC bmi.s loc_3608

ROM:000035FE bsr.w TitleSonic_LoadFrame

ROM:00003602 addq.w #1,($FFFFBE).w

ROM:00003606

ROM:00003606 locret_3606: ; CODE XREF: Iterate_TitleSonicFrame+6j

ROM:00003606 rts

ROM:00003608 ; ---------------------------------------------------------------------------

ROM:00003608

ROM:00003608 loc_3608: ; CODE XREF: Iterate_TitleSonicFrame+12j

ROM:00003608 move.b #2,($FFFFBD).w

ROM:0000360E bra.w loc_3644

ROM:0000360E ; ---------------------------------------------------------------------------

ROM:00003612 SonicFrameIndex:

ROM:00003612 dc.b $2A, $FF, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

ROM:00003612 dc.b $A, $B, $C, $D, $E, $F, $10, $11, $12, $13, $14, $15

ROM:00003612 dc.b $16, $17, $18, $19, $1A, $1B, $1C, $1D, $1E, $1F

ROM:00003612 dc.b $20, $21, $22, $23, $24, $25, $26, $27, $28, $29

ROM:00003612 dc.b $2A, $FF

Compare that SonicFrameIndex to the final:

Code (Text):

SonicFrameIndex: dc.b 1, 2, 3, 4, 5, 6, 7, 8, 9, $A, $B, $FF

However, this is what the frame data index looks like:

Code (Text):

ROM:0000376A TitleSonic_Frames:dc.l ArtKos_TitleSonic0 ; DATA XREF: TitleSonic_LoadFrame+Ao

ROM:0000376E dc.l Pal_TitleSonic0

ROM:00003772 dc.l MapEni_TitleSonic0

ROM:00003776 dc.l ArtKos_TitleSonic0

ROM:0000377A dc.l Pal_TitleSonic0

ROM:0000377E dc.l MapEni_TitleSonic0

ROM:00003782 dc.l ArtKos_TitleSonic0

ROM:00003786 dc.l Pal_TitleSonic0

ROM:0000378A dc.l MapEni_TitleSonic0

ROM:0000378E dc.l ArtKos_TitleSonic0

ROM:00003792 dc.l Pal_TitleSonic0

ROM:00003796 dc.l MapEni_TitleSonic0

ROM:0000379A dc.l ArtKos_TitleSonic0

ROM:0000379E dc.l Pal_TitleSonic0

ROM:000037A2 dc.l MapEni_TitleSonic0

ROM:000037A6 dc.l ArtKos_TitleSonic0

ROM:000037AA dc.l Pal_TitleSonic0

ROM:000037AE dc.l MapEni_TitleSonic0

ROM:000037B2 dc.l ArtKos_TitleSonic0

ROM:000037B6 dc.l Pal_TitleSonic0

ROM:000037BA dc.l MapEni_TitleSonic0

ROM:000037BE dc.l ArtKos_TitleSonic0

ROM:000037C2 dc.l Pal_TitleSonic0

ROM:000037C6 dc.l MapEni_TitleSonic0

ROM:000037CA dc.l ArtKos_TitleSonic0

ROM:000037CE dc.l Pal_TitleSonic0

ROM:000037D2 dc.l MapEni_TitleSonic0

ROM:000037D6 dc.l ArtKos_TitleSonic0

ROM:000037DA dc.l Pal_TitleSonic0

ROM:000037DE dc.l MapEni_TitleSonic0

ROM:000037E2 dc.l ArtKos_TitleSonic0

ROM:000037E6 dc.l Pal_TitleSonic0

ROM:000037EA dc.l MapEni_TitleSonic0

ROM:000037EE dc.l ArtKos_TitleSonic0

ROM:000037F2 dc.l Pal_TitleSonic0

ROM:000037F6 dc.l MapEni_TitleSonic0

ROM:000037FA dc.l ArtKos_TitleSonic0

ROM:000037FE dc.l Pal_TitleSonic0

ROM:00003802 dc.l MapEni_TitleSonic0

ROM:00003806 dc.l ArtKos_TitleSonic0

ROM:0000380A dc.l Pal_TitleSonic0

ROM:0000380E dc.l MapEni_TitleSonic0

ROM:00003812 dc.l ArtKos_TitleSonic0

ROM:00003816 dc.l Pal_TitleSonic0

ROM:0000381A dc.l MapEni_TitleSonic0

ROM:0000381E dc.l ArtKos_TitleSonic0

ROM:00003822 dc.l Pal_TitleSonic0

ROM:00003826 dc.l MapEni_TitleSonic0

ROM:0000382A dc.l ArtKos_TitleSonic0

ROM:0000382E dc.l Pal_TitleSonic0

ROM:00003832 dc.l MapEni_TitleSonic0

ROM:00003836 dc.l ArtKos_TitleSonic0

ROM:0000383A dc.l Pal_TitleSonic0

ROM:0000383E dc.l MapEni_TitleSonic0

ROM:00003842 dc.l ArtKos_TitleSonic0

ROM:00003846 dc.l Pal_TitleSonic0

ROM:0000384A dc.l MapEni_TitleSonic0

ROM:0000384E dc.l ArtKos_TitleSonic0

ROM:00003852 dc.l Pal_TitleSonic0

ROM:00003856 dc.l MapEni_TitleSonic0

ROM:0000385A dc.l ArtKos_TitleSonic0

ROM:0000385E dc.l Pal_TitleSonic0

ROM:00003862 dc.l MapEni_TitleSonic0

ROM:00003866 dc.l ArtKos_TitleSonic0

ROM:0000386A dc.l Pal_TitleSonic0

ROM:0000386E dc.l MapEni_TitleSonic0

ROM:00003872 dc.l ArtKos_TitleSonic0

ROM:00003876 dc.l Pal_TitleSonic0

ROM:0000387A dc.l MapEni_TitleSonic0

ROM:0000387E dc.l ArtKos_TitleSonic0

ROM:00003882 dc.l Pal_TitleSonic0

ROM:00003886 dc.l MapEni_TitleSonic0

ROM:0000388A dc.l ArtKos_TitleSonic0

ROM:0000388E dc.l Pal_TitleSonic0

ROM:00003892 dc.l MapEni_TitleSonic0

ROM:00003896 dc.l ArtKos_TitleSonic0

ROM:0000389A dc.l Pal_TitleSonic0

ROM:0000389E dc.l MapEni_TitleSonic0

ROM:000038A2 dc.l ArtKos_TitleSonic0

ROM:000038A6 dc.l Pal_TitleSonic0

ROM:000038AA dc.l MapEni_TitleSonic0

ROM:000038AE dc.l ArtKos_TitleSonic0

ROM:000038B2 dc.l Pal_TitleSonic0

ROM:000038B6 dc.l MapEni_TitleSonic0

ROM:000038BA dc.l ArtKos_TitleSonic0

ROM:000038BE dc.l Pal_TitleSonic0

ROM:000038C2 dc.l MapEni_TitleSonic0

ROM:000038C6 dc.l ArtKos_TitleSonic0

ROM:000038CA dc.l Pal_TitleSonic0

ROM:000038CE dc.l MapEni_TitleSonic0

ROM:000038D2 dc.l ArtKos_TitleSonic0

ROM:000038D6 dc.l Pal_TitleSonic0

ROM:000038DA dc.l MapEni_TitleSonic0

ROM:000038DE dc.l ArtKos_TitleSonic0

ROM:000038E2 dc.l Pal_TitleSonic0

ROM:000038E6 dc.l MapEni_TitleSonic0

ROM:000038EA dc.l ArtKos_TitleSonic0

ROM:000038EE dc.l Pal_TitleSonic0

ROM:000038F2 dc.l MapEni_TitleSonic0

ROM:000038F6 dc.l ArtKos_TitleSonic0

ROM:000038FA dc.l Pal_TitleSonic0

ROM:000038FE dc.l MapEni_TitleSonic0

ROM:00003902 dc.l ArtKos_TitleSonic0

ROM:00003906 dc.l Pal_TitleSonic0

ROM:0000390A dc.l MapEni_TitleSonic0

ROM:0000390E dc.l ArtKos_TitleSonic0

ROM:00003912 dc.l Pal_TitleSonic0

ROM:00003916 dc.l MapEni_TitleSonic0

ROM:0000391A dc.l ArtKos_TitleSonic0

ROM:0000391E dc.l Pal_TitleSonic0

ROM:00003922 dc.l MapEni_TitleSonic0

ROM:00003926 dc.l ArtKos_TitleSonic0

ROM:0000392A dc.l Pal_TitleSonic0

ROM:0000392E dc.l MapEni_TitleSonic0

ROM:00003932 dc.l ArtKos_TitleSonic0

ROM:00003936 dc.l Pal_TitleSonic0

ROM:0000393A dc.l MapEni_TitleSonic0

ROM:0000393E dc.l ArtKos_TitleSonic0

ROM:00003942 dc.l Pal_TitleSonic0

ROM:00003946 dc.l MapEni_TitleSonic0

ROM:0000394A dc.l ArtKos_TitleSonic0

ROM:0000394E dc.l Pal_TitleSonic0

ROM:00003952 dc.l MapEni_TitleSonic0

ROM:00003956 dc.l ArtKos_TitleSonic0

ROM:0000395A dc.l Pal_TitleSonic0

ROM:0000395E dc.l MapEni_TitleSonic0

ROM:00003962 dc.l ArtKos_TitleSonic0

ROM:00003966 dc.l Pal_TitleSonic0

ROM:0000396A dc.l MapEni_TitleSonic0

The data for the others frames do not seem to exist.
Click to expand...

JoseTB · Nov 18, 2019

drx said:

This build has two leftover palette sets from previous builds. Here are some comparison shots:

There are leftovers from at least two builds in the ROM, which is how it was possible to get LRZ working. Can't wait to see what you guys find.

(ignore the numbers that replace TIME, that's just me)
Click to expand...

JoseTB · Nov 18, 2019

InvisibleUp said:

I'm poking at this with a disassembler. Haven't got too far yet, just got through the level init code, but I'm noticing that the code here seems to be decently between Sonic 2 and Sonic 3. I keep losing track following one disasm and have to pick up on the other one.

More notes:
- Game is not region-locked (like S2)
- Game checks for PAL machines (like S3)
- Checksum code is dummied out; loop instructions are replaced with NOPs
- The game mode list is formatted like Sonic 2's using bra instructions instead of a jump table like S3
- The only game modes present (unless they're there but not in the list) are the Sega screen, the title screen, the level select, the main game mode, and the two special stage demos
- Level art load blocks are the same size as in Sonic 3
- It appears that the game attempts to load the Miles/Tails HUD like Sonic 2
- The "night mode" (shadow/highlight debug mode) cheat from Sonic 2 is still there

Edit 1:
- The "special CNZ bumpers" code and the corresponding check for CNZ are both still present.
Click to expand...

JoseTB · Nov 18, 2019

Rika Chou said:

I got the level map for HCZ1, seems to be identical to final from what I can tell: https://i.imgur.com/iSfjCvh.png

Anyone know if the other levels have layout changes? I could see about getting maps for those.

Also I've done though most of the Nemesis compressed are, so far nothing interesting.
Click to expand...

JoseTB · Nov 18, 2019

Rika Chou said:

Anyone recognize what this is? Looks familiar but I'm not sure: (mappings and palette may be wrong)

($12CC34)

Click to expand...

JoseTB · Nov 18, 2019

Rika Chou said:

Naean said:

SyntaxTsu said:

Rika Chou said:

Anyone recognize what this is? Looks familiar but I'm not sure: (mappings and palette may be wrong)

($12CC34)

Click to expand...

The former is an object also unused in the final game. The latter? No idea.
Click to expand...

Haha, beat me to the punch! I was just about to link to the switch's entry on The Cutting Room Floor for the final version of Sonic 3.

Never seen the object on the right before, however. Maybe it's a door which goes along with the switch, but that's just a guess. Is there any code which may suggest that these objects are likely to be related?
Click to expand...

The block / door looking thing is in the same art file, so maybe they were somehow related.

Here's another possibility for the palette, could be some burnt thing? None of the other AIZ paletttes fit:

Click to expand...

JoseTB · Nov 18, 2019

Rika Chou said:

FBZ act 1 Map
FBZ act 2 Map
FBZ act 2 BG (includes path leading to the boss)

The art for the secret big ring areas is different than final.
Click to expand...

JoseTB · Nov 18, 2019

NeoFusionBox said:

Guess we still can acess other Sonic 2's menu in this proto as well:

Click to expand...

JoseTB · Nov 18, 2019

evilhamwizard said:

So I mentioned on the Discord that some of the songs seem to include a ton of extra instrument patches that go unused. As it turns out, many of the songs are "unoptimized" meaning that they don't rewrite bars into loops and instead plays everything "straight". It's almost as if the prototype is based on a loose conversion of some other sequencing data, and the final version is hand optimized for space.

For example, check out Hydrocity Act 2. It sounds similar to the final, but it's actually very different:

Proto:
https://pastebin.com/aZrqRVTA

Final:
https://pastebin.com/qVPxQ4wV

The proto version contains 34 instrument patches but only uses a few of them. The prototype does not take advantage of looping any pattern of sequencing data and instead just plays everything as is.
Click to expand...

JoseTB · Nov 18, 2019

Rika Chou said:

The last piece of Nemesis art I'm not sure of is this. I'm not sure what palette it's supposed to use, MGZ looks best, and the tiles don't fit together very easily.

Anyway, Here's a folder of all the uncompressed nemesis art, with names. Not sure if it will be helpful to anyone?
Click to expand...

JoseTB · Nov 18, 2019

Vangar said:

I've been playing it on real hardware using an Everdrive, here are my findings i haven't seen mentioned yet

General

Note: At any time if the sound driver screws up, you can pause and un-pause to stop it hurting your ears.

Ring SFX appears to only come from the right channel

If you leave the demo running, it will repeat with sonic's death until a game over, then return to the sega screen.

Tails flight is silent, doesn't appear to have a time limit, and happens in 'bursts'. Tails can carry sonic underwater and can lift him out of it, but is slower. Flight animation used.

Tails appears to come closer after waiting when an act starts

No flashing effect on any shields

The bubble shield animation direction changes when you jump, E: confirmed doesn't happen in S3

Invincibility stars are glitched, show bubble shield graphics

Ending invincibility brings back the level audio, but getting a 1 up or a bubble while almost drowning does not

The sound effect to notify you you're about to start drowning is different

The dynamic loading between underwater and above water in some levels has a visible frame lag that causes the music and everything to skip a frame, sometimes.

You can get sucked into the wall on moving spikes by standing on them

Unused tiles? In red? . Moving pistons?

Carnival Night

There's a sound effect for grabbing onto and releasing from the vertical mesh tumblers

Bumpers use a different sound when struck

There's a yellow barrier that closes to prevent falling into the tubes that fire you upwards, but it tails is underneath it you can continually fall into it, in this area

The sound coming out of a yellow pipe is different, but this may need to be checked because of the common sound issues

CNZ Act 2, the water table moves up and down, pretty sure this is static in the final EDIT: to elaborate from below: I mean that if you just sit in the water, the water level moves up and down like in Aquatic Ruin S2, where in the final it just sits still.

CNZ1 and 2 act music seem to loop... fine... on hardware. CNZ2 loop isn't fantastic but its not out of beat. (On stream people seemed to think it was looping badly?)

Just a note, CNZ2 has musical 'trills' that sound like HCZ2's, making them sound more thematic to the rest of the soundtrack than the (probable) MJ version.

Hydrocity

The bubble shield doesn't stop you drowning

Jumping from the arm conveyors in the water gives you a ton of height

Hitting the turtle badnik locks gives you lots of bounce force backwards (Try spindashing into one, they act like Marble Garden bumpers)

Angel Island

Miniboss rockets have a more realistic sound effect when they launch. In the final, this is a comical pop kind of sound.

When tails first appears in the game, he has a sweeping motion where you can grab on and be taken to the top section without any control from player 2

AIZ1 part two layout is quite different, and shorter. I think there's a unique melody in the middle, not just instruments being different. Also this appears to be the only song that's 'slower' , so I don't think the playback speed is a glitch.

You can hit a yellow spring and catch a rope to swing upside down

There's a small cave section with a spring where the water table doesn't line up properly

Sound Test

One could guess from the sound test order (Matches what we can see in the level select) that the level order is AIZ, HCZ, MGZ, CNZ, FBZ, ICZ, LBZ, MVZ, SZ, LRZ, HP (If it was planned for vanilla S3?), SSZ, DEZ, Doomsday, as all songs are present.

SE40 is in between the shield spawn sound effects, but I don't recognise it, there's already one for the lightning shield, and for the lightning shield action, so I'm not sure what one this is.

Appears that D8 and D9 are leftover from Sonic 2, after that the slots are empty

9F, A0, A1 are Mushroom Valley SFX

EDIT

26: Credits (PC)
28: "No Way? No way!" - Used as the continue music in S3
2D: Competition mode (PC)
2E: Completely Unused
Click to expand...

JoseTB · Nov 18, 2019

Rika Chou said:

SyntaxTsu said:

Rika Chou said:

I'm not sure what palette it's supposed to use, MGZ looks best, and the tiles don't fit together very easily.

Anyway, Here's a folder of all the uncompressed nemesis art, with names. Not sure if it will be helpful to anyone? The last piece of Nemesis art I'm not sure of is this:
Click to expand...

Have you tried using the leftover Lava Reef Zone palette?
Click to expand...

Can't find the proto LRZ palette, but using the final palette looks fitting to me:

Click to expand...

JoseTB · Nov 18, 2019

Vangar said:

Continuing my little hardware play-through, i found a couple of extra things in addition to my previous post:

If you start at ICZ2, you can fly up to the top and go backwards and fight the Act 1 boss in act 2. The end card says you completed act 1.

Getting the speed shoes play the invincibility tune and doesn't stop when the speed runs out

Pressing B on hardware in the menu doesn't seem to do anything (someone said it makes a noise on emulator?)

When Robotnik appears in Marble Garden, the grey numbering in the HUD becomes black, when he leaves, it returns to a light grey

Electric shield doesn't seem to protect you from electric attacks, doesn't reflect projectiles

Marble Garden spikes don't make a noise when they fire projectiles

Haven't seen any bonuses pop out of the ground using a signpost, i don't think they exist.

I've edited my original findings post with confirmations and notes after I went back to S3 vanilla to check also.

EDIT: What is the debug code so I can use it on hardware? EDIT 01, 03, 05, 07 and hold A+Start on a level
Click to expand...

JoseTB · Nov 18, 2019

Prototype said:

So, this isn't particularly a groundbreaking post and I'm sure everyone's found the major tidbits. But for what it's worth, despite the lack of a functional Slot Machine bonus stage, from what I can tell in the VDP viewer, that unused Super Sonic reel sprite is still loaded into VRAM (if I'm getting my ROM terminology correct)

Click to expand...

Sonic 3 (Nov 3, 1993 prototype) - Technical Analysis & Research thread

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