SCD savestates

Hayate · Aug 20, 2004

Ok, I made a savestate in SCD and loaded it into S2 with SonED. Now all the 8x8s are there, but the 16s and 128s are messed up. Why is this? Does SCD use 256x256s like S1? I also thought of loading up SCD in SonED, but it says it cannot identify the ROM. Any ideas? :huh:

Erik JS · Aug 25, 2004

I'll just try to explain what happens on SCD...

As you know, 8x8 tiles are in the same old 0000 address from VRAM for all Sonic games (I.e. 1-2b-2-CD-3K). Now here comes the funny thing: SCD still uses the 256x256 blocks from S1, but 16x16 and 256x256 mappings had their places changed.
In a Gens Savestate, 16x16 mappings are in 4478-5477. Level layout is in C878-CC77 (same as S1), but 256x256 are nowhere to be found in the RAM! For all levels, they start at 0x010000 and end God knows where. "All levels" means all R*.MMD files. For instace, R11A__.MMD is Palmtree Panic 1 - Present (you guess the rest).

Both 8x8 and 16x16 are compressed in Nemesis format in MMD files. The 256x256 aren't for obvious reasons.

I have a hacking guide that covers CD Sonic (Beta 510). I even made a CDStoS1 conversor, but it's all in Portuguese!
http://geocities.yahoo.com.br/erikjs_br/cdsonichack/
http://geocities.yahoo.com.br/erikjs_br/cd...ack/cdsc100.zip

I hope that helped!

Rika Chou · Aug 26, 2004

Erik JS said:

I'll just try to explain what happens on SCD...

As you know, 8x8 tiles are in the same old 0000 address from VRAM for all Sonic games (I.e. 1-2b-2-CD-3K). Now here comes the funny thing: SCD still uses the 256x256 blocks from S1, but 16x16 and 256x256 mappings had their places changed.
In a Gens Savestate, 16x16 mappings are in 4478-5477. Level layout is in C878-CC77 (same as S1), but 256x256 are nowhere to be found in the RAM! For all levels, they start at 0x010000 and end God knows where. "All levels" means all R*.MMD files. For instace, R11A__.MMD is Palmtree Panic 1 - Present (you guess the rest).

Both 8x8 and 16x16 are compressed in Nemesis format in MMD files. The 256x256 aren't for obvious reasons.

I have a hacking guide that covers CD Sonic (Beta 510). I even made a CDStoS1 conversor, but it's all in Portuguese!
http://geocities.yahoo.com.br/erikjs_br/cdsonichack/
http://geocities.yahoo.com.br/erikjs_br/cd...ack/cdsc100.zip

I hope that helped!
Click to expand...

Wow, you know your stuff.

Qjimbo · Aug 26, 2004

:shocked:
Flippin heck, this could end up being the first time a trial member ever been promoted straight to tech member with that kind of knowledge

Welcome to the board!

voice · Aug 26, 2004

Holy shit this guy is good! just.........wow ^_^ Hopefully the hack guide could help with other problems that Gens is having playing music correctly after leaving special stage

LOst · Aug 26, 2004

Erik JS said:

I'll just try to explain what happens on SCD...

As you know, 8x8 tiles are in the same old 0000 address from VRAM for all Sonic games (I.e. 1-2b-2-CD-3K). Now here comes the funny thing: SCD still uses the 256x256 blocks from S1, but 16x16 and 256x256 mappings had their places changed.
In a Gens Savestate, 16x16 mappings are in 4478-5477. Level layout is in C878-CC77 (same as S1), but 256x256 are nowhere to be found in the RAM! For all levels, they start at 0x010000 and end God knows where. "All levels" means all R*.MMD files. For instace, R11A__.MMD is Palmtree Panic 1 - Present (you guess the rest).

Both 8x8 and 16x16 are compressed in Nemesis format in MMD files. The 256x256 aren't for obvious reasons.

I have a hacking guide that covers CD Sonic (Beta 510). I even made a CDStoS1 conversor, but it's all in Portuguese!
http://geocities.yahoo.com.br/erikjs_br/cdsonichack/
http://geocities.yahoo.com.br/erikjs_br/cd...ack/cdsc100.zip

I hope that helped!
Click to expand...

Ahhhh! A trial member from nowhere knowing so much!

Anyway, the 256x256 block would be at $FF0000.w in RAM in Sonic 1. Now, in Sonic CD they are probably put into other M68k RAM space that the Sega CD has.

If the Debug Gens can dump RAM, maybe it can dump the RAM from the Sega CD's M68k RAM space too, and by that you can fake a savestate and get the info into SonED?

Syren · Aug 26, 2004

Erik JS said:

I'll just try to explain what happens on SCD...

As you know, 8x8 tiles are in the same old 0000 address from VRAM for all Sonic games (I.e. 1-2b-2-CD-3K). Now here comes the funny thing: SCD still uses the 256x256 blocks from S1, but 16x16 and 256x256 mappings had their places changed.
In a Gens Savestate, 16x16 mappings are in 4478-5477. Level layout is in C878-CC77 (same as S1), but 256x256 are nowhere to be found in the RAM! For all levels, they start at 0x010000 and end God knows where. "All levels" means all R*.MMD files. For instace, R11A__.MMD is Palmtree Panic 1 - Present (you guess the rest).

Both 8x8 and 16x16 are compressed in Nemesis format in MMD files. The 256x256 aren't for obvious reasons.

I have a hacking guide that covers CD Sonic (Beta 510). I even made a CDStoS1 conversor, but it's all in Portuguese!
http://geocities.yahoo.com.br/erikjs_br/cdsonichack/
http://geocities.yahoo.com.br/erikjs_br/cd...ack/cdsc100.zip

I hope that helped!
Click to expand...

Refreshing, a Trial dude that knows his stuff.

It makes me wonder why I am a member.

JoseTB · Aug 26, 2004

Erik JS said:

For all levels, they start at 0x010000 and end God knows where.
Click to expand...

Teorically it should be 41983 bytes ($0000 - $A3FF in sonic 1) At least I think that it is the max to s1.However,MapXXX.bin in scd from pc is 65536 (Is the content of $10000 in mmd files).

By the way,I saw that you have missing some info about the collisions(in the guides),needed to port correctly zones,so here it comes:

(This is ONLY for sonic cd beta 510 mmd files):

$3870C-$3880B : Curve and resistance data
$3880C-$3980B : Collision array 1
$3980C-$3A80B : Collision array 2
$3A80C-(undetermined,I guess that it changes the size for each zone) : Collision Data

Hivebrain · Aug 26, 2004

Teorically it should be 41983 bytes ($0000 - $A3FF in sonic 1) At least I think that it is the max to s1.
Click to expand...

SCD uses a much greater number of 256x256 tiles per level. This can be a problem when porting SCD->S1 levels.

Hayate · Aug 28, 2004

Um. Let me clarify, I don't have the PC version, I have the SegaCD version. Does that make a difference? Are the MMD files you talk about inside the ISO file (WinRAR says it's an archive, not a ROM)?

Quickman · Aug 28, 2004

ISO != ROM

WinRAR can open ISOs since it knows they're CD images and treats them as such.

Erik JS · Aug 31, 2004

WinRAR handling ISO's... I never noticed it before! I use Daemon Tools, which is some kind of CD emulator that loads images into a virtual drive.
http://www.daemon-tools.cc/

JoseTheBest: thanks for the info. I'll add it to the guide sooner or later... later...

Hayate · Aug 31, 2004

Um, was that even relavent? :\

SCD savestates

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