Sonic 3 & K research (S&K also)

I originally made this topic on Retrohack (PsychoSk8r's forums), but I decided to copy/paste what I had here. enjoy.


So you want to hack S3K, or port an object from said game?


You've looked all over this site AND asked for help, only to find that nobody can help you?


You wonder why you cannot be helped?


Here is the answer: Sonic 3 and Knuckles is not as well documented as the other two games.


I want to fix that. Who's with me?


My S3K research is only possible because of Stealth's Sonic3k.asm file. So a big thanks to Stealth. (and Puto for his text format conversion. )


1. you will need a copy of Stealth's S&K ASM file, which you can grab from Sonic Retro (guys, If you don't want me to link to Retro, tell me, I can find a host): DOWNLOAD


Then, if you can figure out how, lock-on S3 with the ASM.


Here are the instructions from the IDA version of the Stealth disassembly:

In order to build a rom you will need include.exe, snasm86k.exe (OR ASM68k.exe) and you must also make a build.bat file using the following text:

OR, if you use ASM68k.exe:

2. don't be afraid to share and ask questions in this topic.


The sole purpose of this topic is to research S3K and compare it's equates, RAM variables and routines to Sonic 2.


What good is this?


It will help provide people with answers to unknown questions, as well as help you, the hacker.


How will it help?


Not only will we be able to further understand S3K, but it will also aid in porting objects to the other Sonic games, Such as Sonic 1 and 2.


To start this all off, I will post my findings. All of my findings have been compared to their Sonic 2 (xenowhirl ASM) equivalents.


Sonic 2 on the left, S3K on the right:



S2 to s3k equates:

Sonic_acceleration: = 2 ; this seems to handle topspeed as well, i guess...


Sonic_deceleration: = 4 ?


render_flags: = 4 ?


routine: = 5


width_pixels: = 6 ;and 7 ?


priority: = 8 ; $100 is 2 in s2 and $80 is 1


art_tile: = $A


mappings: = $C


x_pos: = $10


y_pos: = $14


x_vel: = $18


y_vel: = $1A


inertia: = $1C


y_radius: = $1E AND 6?


x_radius: = $1F AND 7?


anim: = $20


next_anim: = $21


mapping_frame: = $22


anim_frame: = $23


anim_frame_duration: = $24


angle: = $26


flip_angle: = $27


collision_flags: = $28


collision_property: = $29


Status: = $2A


status_secondary: = $2B


air_left: = $2C


flip_turned: = $2D


obj_control: = $2E


;routine_secondary: = $2F


flips_remaining: = $30


flip_speed: = $31


move_lock: = $32


invulnerable_time: = $34


invincibility_time: = $35


speedshoes_time: = $36


$38 = $38 ; custom in s2... I use it for shield art. S3K uses it to check for player modes: 1 for tails and 2 for Knuckles


Sonic_Look_delay_counter: = $39


next_tilt: = $3A


tilt: = $3B


stick_to_convex: = $3C


shield_dplc: = $3C ; custom in s2... not sure if it will work in all hacks =/


spindash_flag: = $3D


spindash_counter: = $3E


layer_plus: = $3F


Jumping: = $40


layer: = $46


layer_plus: = $47


next_object: = $4A


RAM variables:


Ctrl_1_Held_Logical = $FFFFF602


Ctrl_1_Press_Logical = $FFFFF603


Ctrl_1_Held = $FFFFF604


Ctrl_1_Press = $FFFFF605


Sonic_Pos_Record_Index = $FFFFEE26


Sonic_Pos_Record_Buf = $FFFFE500


Sonic_Stat_Record_Buf = $FFFFE400


$FFFFB01A = $FFFFB022


$FFFFB001 = $FFFFB004


$FFFFB018 = $FFFFB008


$FFFFEE24 = $FFFFEE24


$FFFFCD9C = $FFFFCD9C


$FFFFF602 = $FFFFF602


PlaySound = Play_Sound_2


Primary_Collision = $FFFFF7B4


Secondary_Collision = $FFFFF7B8


Collision_addr = $FFFFF796


Chain_Bonus_counter = $FFFFF7D0


Camera_Min_Y_pos = $FFFFEE18


Camera_Min_X_pos = $FFFFEE14


Camera_Max_X_pos = $FFFFEE16


Debug_mode_flag = $FFFFFFDA


Ctrl_1_Press = $FFFFF605


Debug_placement_mode = $FFFFFE08


Control_Locked = $FFFFF7CA


Camera_Max_Y_pos_now = $FFFFEE1A


$FFFFEEBE = $FFFFEE0B


Update_HUD_lives = $FFFFFE1C


Update_HUD_rings = $FFFFFE1D


Life_count = $FFFFFE12


Time_Over_flag = $FFFFFE1A


Update_HUD_timer = $FFFFFE1E


Update_HUD_timer_2P = $FFFFFEC7


Ring_count = $FFFFFE20


Extra_life_flags = $FFFFFE1B


Level_Inactive_flag = $FFFFFE02


RandomNumber = Random_Number


Emerald_count = $FFFFFFB1


$FFFFFFB0 = $FFFFFFB0 ; used as Got_Emerald in s2, but in S3K, it is used to check the super emeralds


MainCharacter = $FFFFB000


Object_RAM = $FFFFB000


Sidekick = $FFFFB04A


Water_flag = $FFFFF730


Super_Sonic_flag = $FFFFFE19


Ring_spill_anim_counter = $FFFFFEB6


Extra_life_flags = $FFFFFE1B


Saved_layer = $FFFFFE3A


Saved_art_tile = $FFFFFE38


Saved_x_pos = $FFFFFE2E


Saved_y_pos = $FFFFFE30


$FFFFF7C7 = $FFFFF7C8


$FFFFF768 = $FFFFF768


$FFFFF76A = $FFFFF76A


obj_control = $FFFFF7C6


Super_Sonic_frame_count = $FFFFF670


$FFFFCBC0 = $FFFFCBC0 ; used in S3K for hyper form after-images


MoveX = $FFFFB018


MoveY = $FFFFB01A


MainCharacter+x_pos = $FFFFB010


MainCharacter+y_pos = $FFFFB014


Sidekick+x_pos = $FFFFB05A


Sidekick+y_pos = $FFFFB05E


Routines:


PauseGame = Paused_Debug_Controls


Sonic_LevelBound = Player_Check_Screen_Boundaries


AnglePos = Call_Player_AnglePos


CalcSine = GetSine


CalcAngle = GetArcTan


Sonic_DoLevelCollision = sub_11EEC


ObjectMove = MoveSprite_TestGravity2 or MoveSprite2


SingleObjLoad = Create_New_Sprite3


AnimateSprite = Animate_Sprite


DisplaySprite = Draw_Sprite


sonic_jumpheight = sub_118BC


Sonic_ChgJumpDir = sub_1164E


Obj01_UpdateSpeedOnGround = loc_112FC


Sonic_Lookup = loc_112B0


Sonic_Duck = loc_11276


Obj01_MdJump = Sonic_Spin_Freespace


Obj01_MdRoll = Sonic_Spin_Path


Sonic_Roll = Player_Spin


Sonic_Jump = sub_117DA


Player_OnFloor = loc_1C95A or Tails_DoLevelCollision when Tails


Sonic_CheckGoSuper = loc_119D2


Sonic_ResetOnFloor = Player_TouchFloor



Not 100% sure on some notes, 4 seems to be both Sonic_deceleration AND render_flags, but that may just be me overlooking shit.


click this link for information on this: link


Enjoy, and help out if you can.


EDIT: I am aware of the Sound issues, and the fact that building with SNASM68k screws with the character art.


If anyone knows how to fix these problems, please post the information.

 

I've been trying to do the same thing in a way so This Topic I created should help. It's got everything thats in Sonic 3 that can't be accessed normally but is in the game and can probably be accessed in S3 through ASM. So I help with your research.

 

Ok so I built the disassembly. But if I play the game, there's no sound after SEGA screen and Sonic looks messed up in the game.

 

I have the Sound Problems as well. It's like "SEEEGAAAA...*chrash-sound*" and no sound. Sonic is not looking messed up for me, but a game without sound is useless.

 

Snasm or asm8k?


Also, I am aware of the sound issue..although, unsure on how to fix it.

 

Well, I used ASM68k to build. I guess SNASM68k is shit to build this. But I don't know why thi is happening. Maybe the file is too large... I dunno.

 

That's because you are reading it wrong. 4 (or $04) is render flags. What you are thinking of is something that is put into register (a4) at the begining of Obj_Sonic's code, this:



move.w #$80,4(a4)



If you scroll up to the beginning of Obj_Sonic, you will see this:



lea ($FFFFF760).w,a4



Now when you move an address into a register, like (a4), putting a number in front of it like 4 adds 4 to the current address. So that above line of code,



move.w #$80,4(a4)


is actually the same as writing

Code:

		move.w	#$80,($FFFFF764).w

Sorry if this doesn't make sense, I'm sick and can't think like normal.

 

Stealth knows

 

Okay I've made that, but now I've got a 1KB build.

 

Snkenjoi, thanks for that link.


I'll have to try that out when I get home tomorrow. (I'm at my GF's, using a Wii for the internet.)

 

Yes, he really knows. I fixed it (replacing hundreds of $FF with a simple cnop ).


Source Code aviable here (including ASM68k, corrupted SNASM68k, ROMPAD, INCLUDE and 2 custom build.bat files): LINK


Complete Credits to Stealth (except for uploading the Source Code)

 

...


That guide was seriously unrequired you know.

 

I know, but it wouldn't make any differences, when I haven't added it. But actually you're right. Guide removed (download the File ).

 

Okay, I made it. But now anything sounds crappy. My proof is on the attachment.S3K_SNAS.rar

 

I really don't know your problem. Maybe there is something wrong with your SNASM68K.EXE... As for the sprites, I had the same problem with Hitaxas build.bat. Use mine and everything should work.

 

I'm not too sure what it is either, but using asm68k.exe works for me with no problems. Once I get home, I'll be uploading a small hack of S&K I put together.


Thanks for the interest in this topic.

 

Can anybody tell me what to do to get Sonic 3 & Knuckles? I don't get what in the begining stands and this doesn't help as well... hope someone can say it a bit proper.

 

Selbi, the link is down, can you upload the link again please?

 

That's what Private Messages are for.

 

I deleted it a long time ago. I made my own buildtools a few months ago, but I highly recommend snkenjoi's. they are a million times better (and for some reason don't glitch up the sound even with MusicPadding being normal).


But Hanoch is right, a one and a half years bump doesn't really push yourself into the right light.