SA1 analog drift fix, release of Dreamcast Image Builder, Autodemo research and more

It’s been an eventful couple of months, so there are several things I’d like to talk about today.

New version of the SA1 analog fix

You may have heard of the analog deadzone fix for SA2 DC by OnVar. I was looking at input code in SA1 and found many similarities, so I made a request to woofmute, who successfully ported OnVar’s fix to SA1. The fix is available for the US version (1.005) and the Autodemo. I’m not sure whether the issue is addressed completely or if the fix has any side effects, but it appears to work and it’s definitely better than my old hack, so I suggest you give it a try.

The fix injects custom code into 1ST_READ.BIN. The patched bytes for the US version are as follows. With some patience you could turn it into a very long CodeBreaker code…

;Input function hijack
411e2=0ce0f6f3f5f34c8925c708f235f2488908a10ce0

;Input Patch block 1
41284=20e0f6f304c708f2f5f3b28935f2b08920e0b6aff7ff

;Input Patch Orig code reposition
41406=f7ff20e0f4aef6f3

;float for block 1
4129c=000040c5

There are two ways to get the patch:

  1. If you have the TOSEC GDI of SA1 US 1.005, you can apply an xdelta patch to track03.bin. It works the same way as the SA2 patch in the description of the video linked at the top of this post, so you can use the video for reference.
  2. To apply this fix and more, you can use the new Dreamcast Image Builder that I will talk about in the next section. The Autodemo version of the fix is also available for Dreamcast Image Builder.

Release of Dreamcast Image Builder

This is an update to SA1-DC-HD, a project that originally started as a helper tool to add various enhancements to SA1 DC for playing on the flycast emulator. The project has grown to become a universal patcher for Dreamcast games.

As you can see, it’s heavily inspired by the SADX Mod Loader/Mod Manager and uses the same concept of “mods” to add hacks to games. Of course it’s a lot more limited than the actual Mod Loader, but you can do neat things with it. For example, to test its capabilities I made a mod that replaces Deer with Sheep from SA2:

(Chao body parts not implemented yet)

You can check it out here. All mods from SA1-DC-HD are built-in, so you can use it right away. The wiki explains how to use the tool and develop mods for it.

New Autodemo research

You may have seen new videos uploaded by Speeps and woofmute which demonstrate various debug features of the Autodemo and levels that didn’t work before, such as Casinopolis. This was made possible thanks to the research done by Speeps, woofmute and other members of x-hax, as well as previous research by evilhamwizard, ItsEasyActually, supercoolsonic and others.

As you may know, parts of the Autodemo come from different builds of the game that were at different stages of development. When the Autodemo was put together, only the levels that were meant to be shown in the demo were recompiled, and the other levels were left over from older builds (for most of these, textures and lighting files were also missing). We can tell which binaries were recompiled by looking at file dates on the Autodemo GD-ROM:

15.10.1998 - binaries that boot without hacking

STG01 (Emerald Coast)
STG04 (Speed Highway)
STG05 (Red Mountain)
STG08 (Ice Cap)
STG10 (Final Egg)
ADV00 (Station Square)
ADV00OBJ (Station Square objects)
ADV0100 (Egg Carrier Outside)
ADV0130 (Egg Carries Inside)
ADV01OBJ (Egg Carrier objects)
AL_GARDEN00 (Station Square Chao Garden)
AL_MAIN (Chao)
B_CHAOS2 (Chaos 2)

07.10.1998 - binaries that don't boot without hacking

AL_GARDEN01 (Egg Carrier/Beta Windy Valley Chao Garden)
AL_GARDEN02 (Mystic Ruins Chao Garden)
AL_RACE (Chao Race)

24.09.1998 - binaries that don't boot without hacking

STG00 (Test stages)
STG02 (Windy Valley)
STG03 (Twinkle Park)
STG06 (Sky Deck)
STG07 (Lost World)
STG09 (Casinopolis)
ADV02 (Mystic Ruins)
ADV02OBJ (Mystic Ruins objects)
SHOOTING (Sky Chase)
MINICART (Twinkle Circuit)
B_E101_R (E-101 MK2)
B_ROBO (ZERO)
B_EGM1 (Egg Hornet)
B_EGM3 (Egg Viper)
SBOARD (Sand Hill)
B_CHAOS0 (Chaos 0)
B_CHAOS4 (Chaos 4)
B_CHAOS6 (Chaos 6)
B_CHAOS7 (Perfect Chaos)

You can see that there are three “sets” of files sorted by last modified date. The files that don’t boot were compiled against an earlier version of the game’s main binary (1ST_READ.BIN), so the pointers to functions and data in the main binary are all invalid in these files. However, it’s possible to find the functions and data they were meant to point to by comparing the pointers to known functions and data between these files and the files that boot.

Earlier work on this, which demonstrated partially functional Windy Valley and Sky Deck, was posted by evilhamwizard on Sonic Retro. More recently this was picked up by Speeps, who started putting together a list of known broken pointers and their correct counterparts. As the pointer list grew, more levels became functional when known pointers were replaced. To facilitate mass pointer replacement and game testing, I added Autodemo support to my SA1-DC-HD project (now Dreamcast Image Builder). As we were experimenting with the Autodemo, I adjusted the image builder’s mods system to be more flexible and easier to use and converted (together with woofmute) Speeps’ modifications into mods for it. I also repurposed some of my previous work to find missing textures by matching the names in the Autodemo’s texture lists against textures in the final version, the E3 build, the Autodemo Windy Valley mod for the PC version (where missing textures were recreated by its developers) and Dreamcast SDKs (which surprisingly have some early SA1 textures).

As a result of this combined effort, we got the game to show stuff that was never seen before. For example, here’s a preview of the old version of Chao Race restored by Exant:

Or a very early version of the Mystic Ruins:

Or woofmute’s restoration of the debug object placement editor:

Or a super early version of Twinkle Circuit:

Of course, you also have Speeps’ near-complete restorations of Twinkle Park, Lost World and Sky Deck. The biggest restoration so far is the early Windy Valley, the holy grail of the Autodemo for many SA1 fans. It’s based on Speeps’ and evilhamwizard’s pointer fixes and uses textures from the 2018 PC mod by supercoolsonic & ItsEasyActually.

There’s a lot more stuff released and in progress. We now have a public repository with some Autodemo mods, which you can apply with Dreamcast Image Builder to get the restored functionality and content ingame.

Note: Not all of the mods work on hardware at the moment. flycast is recommended.

The fascinating Korean version of SADX PC and release of the Korean mod

TLDR version: There was a Korean version of SADX PC released back in 2004. I ported the Korean translation to the Mod Loader, so you can now play SADX in Korean if you install this mod. The mod is compatible with Dreamcast Conversion and Dreamcast DLC but incompatible with HD GUI.

Four years ago I got my hands on a somewhat rare version of SADX PC. I was completely unaware of its existence until I accidentally ran into a listing on an auction, so I got it right away. I’ve mentioned it before in a previous post, and today’s mod release brings the occasion to finally talk about it again.

Introduction and game package

This version was released in July 2004 in Korea by a game and toy company called Sonokong. It’s a complete Korean translation of the game with English voices. The game comes in a box with a fully translated manual, which is also in color! It looks a lot better than black-and-white Japanese and US manuals I’ve seen until now. Here are some pictures of the box, the discs and the manual. Please excuse the poor picture quality, maybe someday I’ll get to scanning these properly.

Installation and initial testing

Just like the US version, the game comes on two CDs. The simple CD check is also the same, so you can install and run the game on Windows 10 and above, unlike the Japanese version which no longer works because of SafeDisc. With the Korean version, you can pass the CD check even with the US version’s CD 2.

The autorun and the installer are also fully translated.

I can’t comment on the quality of the localization since I don’t read Korean, but I can say for sure a lot of work was put into it. Unlike French, Spanish and German translations that come with the US and Japanese versions, this one translates not only all textual data, but also all menu textures, the title screen and the main menu background. But the most impressive part is the Korean font used for subtitles and Chao Garden messages. To my knowledge, this is the only official release of SADX that introduces both asset and programming changes to accommodate a language that wasn’t in the original game. It’s also executed in an interesting way, which we will get to a bit later.

As amazing as this version is, it’s still the 2004 PC port of SADX at its core, so the game has terrible graphics with no mipmaps, broken windowed mode at non-4:3 resolutions, poor music quality etc. It’s pretty hard on the eyes, especially in motion.

(From now on, I’ll be using screenshots from the US version with the Mod Loader and the Korean mod)

Korean localization and option menu differences

Korean text replaces Japanese in this version. English text is also available, although the title screen and the main menu background will always use the Korean versions of the textures. The game doesn’t let you pick Japanese voice language, so only English voices can be used. Interestingly enough, Japanese voices are still included with the game: it just doesn’t show the voice language setting in the options menu and overrides the voice language variable with English as soon as a save file is loaded. However, before a save file is loaded the game still plays the “Select a file” voice from the Japanese voices folder. To work around it, the developers replaced that voice with its English counterpart. The rest of the Japanese voices are untouched.

I’m not entirely sure, but I think such elaborate workarounds to make sure no Japanese is heard in the game may have had something to do with Korean laws regarding Japanese media, which were stricter when the game came out.

Funnily enough the texture for the option was still translated, so when you use the mod on the US version with the Mod Loader, you can select Japanese voices as if the option was intended to be there originally (although it says “Korean” instead of “Japanese”). You can also select other languages for text (not sure if you’d really need to if you’re playing this!), which the Korean version doesn’t let you do.

The localization has everything you’d expect, including character tutorials, Mini Game Collection etc.:

Reverse engineering the Korean font

The implementation of the font used in the last two screenshots is intriguing. What caught my attention initially was the large size of the FONTDATA0.BIN file, which is used for Japanese characters in the original version (1.72MB vs 759KB in the original). My first guess was that they either replaced Japanese characters with Korean ones, or added them to the end of the file with the IDs matching the Korean codepage 949.

I started inspecting the file in SADXFontEdit in SA Tools. As expected, this file contains Hangul characters used to display Korean subtitles and Chao texts. However, apart from those, the file also has some characters from other languages, including Greek, Russian, Chinese and Japanese, which amounts to a total of 20609 characters (for comparison, the original file used for Japanese has only 8836, and almost all of those are Kanji, although Cyrillic and some other characters are present as part of the Japanese codepage). On top of that, soon I realized that character IDs stored in the file matched those of the codepage 1200 (UTF-16).

Yes, you read that right. In the Korean version of the game the subtitle font is an actual Unicode font. Although it only supplies specific blocks of the Basic Multilingual Plane, in theory you could add back the other blocks to implement any language included in the plane. Back in 2020 when I first discovered this, I updated SADXFontEdit with some new functionality, including support for the Unicode layout, so when you select the correct codepage you can see the matching character next to its ID.

As we know, the US and JP versions don’t support Unicode, so how does this work? The game’s dialog texts, menu prompts etc. were compiled into the game as strings encoded with the Korean codepage 949, not Unicode. However, when the game processes text data to create a subtitle texture, it parses the characters and assigns them Unicode IDs to be used to pick graphics from the font data you see in the screenshots above.

This was where I ran into an issue I didn’t understand at first. When I first ran the game, it would either display garbage text in place of subtitles, or just crash. That was how I found out that the Korean version required the system locale (language for non-Unicode programs) to be set to Korean for subtitles to render properly.

If the game already knows it’s converting Korean to Unicode, why does it need that? Eventually I found the answer when I was looking at the game’s font related functions in the disassembly that I quickly cobbled together. The Korean version uses the function MultiByteToWideChar to convert “C strings” (in this case Korean strings in the local codepage) to UTF-16 “wide strings”. It’s an interesting solution considering that other versions have a custom function to parse characters and assign font IDs to them.

So why does it fail when the system locale isn’t set to Korean? The developers call the function with the default first argument (0), which takes the current system locale as the source codepage. As a result, Korean text is converted to Unicode as if its original codepage is whatever you have set as the language for non-Unicode programs. If the developers of the Korean version set the first argument of MultiByteToWideChar to 949, the Korean version would display subtitles correctly on any system regardless of the locale. I think a lot of people would’ve never caught this issue because the game was meant to be sold only in Korea. Anyway, we can fix this on the mod’s side.

Implementing code differences

With such changes to the font system, simply replacing FONTDATA0.BIN in a mod wouldn’t make the game support Korean, and a bunch of hacks had to be done first. One thing to do was to introduce calls to MultiByteToWideChar before letting the game parse text data. As I didn’t know the stuff I explained in the previous paragraphs, it took me a while to realize the importance of these calls, and my initial attempt to get the game to display Korean text correctly were unsuccessful. I gave up on the mod for a while, and it was only this month that I gave it another try and figured it out. Another necessary change was in the function that maps character IDs to bitmap data in the font file. There were overrides for , and , but other than that it was pretty straightforward.

I put together a DLL mod that replaces three text-related functions, then I replaced one Japanese hint message in Emerald Coast to test it. The Mod Loader used a hardcoded codepage for strings that are normally in Japanese, so I added global codepage overrides for all languages, which can now be used by other mods.

At first I wasn’t sure how far I could go with this, but when I finally saw the Mod Loader display Korean text, making a Korean mod started looking feasible. I was also driven by the technical challenge and the uniqueness of this version of the game, support for which required several changes to our tools, which I was happy to implement.

Extracting and importing Korean text

Speaking of technical challenges, obviously I had to somehow extract all Korean text from the game and put it into the mod. Finding it all manually was out of the question, which was part of the reason I gave up on the mod last time. However, after my experience with matching assets between different versions of the game, I was tempted by the idea of automatic splitting. Since the game still has English text, it’s possible to scan the EXE to find it, and then work up the structures to get to the start of each item. There were three types of data that had the largest amount of text: cutscene text, Tikal hints and multi-language strings such as character unlock messages, menu prompts etc. I put together a program to make the task easier. Basically it created an INI file for SA Tools’ split tool to extract the text from the Korean EXE. Of course some manual tweaks were required to ensure all addresses were correct, but the program did most of the tedious work. Cutscene text in particular required almost no touch-ups because I made it verify the text in other languages to ensure it’s the same entry in both games.

Building a mod from this data in SA Tools was a challenge. I had to add custom codepage support and fix a few bugs, but mod building in the tools is more stable now and the end result was worth it.

At this point I ran into an issue many retranslation mods had to deal with. There was some text in the game that wasn’t supported by the Mod Loader and/or the SA Tools at the time. It’s still possible to replace such text in a DLL mod, but I wanted all text replacement to be done via the Mod Loader’s INI-based system, so I had to do some work on the tools again. I added support for the following data types, which can now be replaced in mods without code:

  • Tikal hints that show up after you die on a boss. These are different from the hints you see in stages, and they’re stored in different ways depending on the boss, so I had to improvise a bit to make them rippable in the tools and replaceable in the Mod Loader.
  • Mission descriptions for Mission Mode.
  • Mission Mode tutorial text.
  • Single language strings, such as unlock prompts for Game Gear games or Metal Sonic. I added them to the SA Tools a couple years ago but not to the Mod Loader.
  • Multi-language strings, such as character unlock messages or “Welcome to Twinkle Circuit!”. Same as above.

Implementing Chao texts

With all that in place, all Korean text in the game was finally transferred. There was one big obstacle remaining: Chao texts. Although it loads the same font data, the Chao text system in SADX uses completely different code from the system used by subtitles and menu prompts, probably because it was copied from SA2B and duct taped with the SADX font system. So I had to do the same thing I did for the subtitles for the Chao text functions. This was probably the most difficult part of the whole mod. The functions involved with SA2B text were all difficult to hook, and even when I managed to replace them correctly I would only get crashes. It took me a long time to get a working decompilation of the functions that convert strings for the SA2B system. I’d like to thank Kell for a decompilation of these functions in the US version, which I used for reference.

Interestingly enough, the Chao system also uses wide strings internally, but all text is stored in the Japanese codepage, or Korean in this case. The game performs conversion from C strings to wide strings just the same, but the Korean version uses MultiByteToWideChar again instead of the simple parsing function used for Japanese in the original version.

After many hours of debugging I finally figured out the error in my decompiled code that was related to finding character data. In the pseudocode I got by decompiling the Korean version, the cell ID of the character data in the font was calculated by adding 0x776A to the character ID, which made it go out of range. The sign had to be flipped to make it subtract 0x8896 instead. After I fixed that, the text started working.

Now the mod was ready for testing. Out of curiosity I tried it with Dreamcast Conversion and realized that the Dreamcast Chao Garden hints were missing. Luckily they were translated in the Korean version, so I added them to SA Tools, made some changes to DC Conversion to make it more compatible with mods that replace them, and reimported the translated hints. I was happy that even the normally unused Dreamcast hints were translated.

Mod download, compatibility and conclusion

SA Mod Manager 1-click install
Manual download

The mod is compatible with Dreamcast Conversion, but with a few quirks. Since there are no Dreamcast menu textures in Korean, Dreamcast Conversion’s replacement of some GUI textures will be undone by this mod. This is a quick fix, and I might update it with proper compatibility eventually. There may be bugs in the mod, particularly crashes. Please send me crash dumps if you run into any.

For obvious reasons HD GUI is incompatible. If you’re interested in making HD Korean textures and an HD Korean subtitle font, please let me know.

This is the first translation mod that works by replacing the Japanese font, and the first to modify font-related code. I hope this release attracts more Korean players to SADX modding and helps other translation mods. I also think it’s truly amazing that after all these years of research and reverse engineering there are still new things about this game waiting to be discovered.

The mod’s source code is located here.

SADX Mod Installer update

The SADX Mod Installer was discontinued back in 2022. However, with the arrival of the new SA Mod manager and retirement of the original SADX Mod Manager I felt it was necessary to update it. Many people are still using it, and Linux/Steam Deck tutorials seem to rely on it. Although I want to retire the installer as soon as possible, I made the following update to make it easier for people using it right now:

  • If you’re running Windows 7 or above, it will install the new SA Mod Manager (auto picking x86 or x64). If you’re running Windows XP, it will install the legacy SADX Mod Manager.
  • .NET 7.0 Desktop (x86 or x64) is installed automatically on Windows 7 and above.
  • The installer was made compatible with Windows XP. All tools, including Steam conversion, are completely functional on XP. Online functionality will not work on XP and 7 due to outdated certificates, but it might work if the system has correct certificates.
  • The Steam conversion process has been altered to rely on patches. Now the installer doesn’t supply the EXE or DLLs from the 2004 version, instead it patches the Steam version to turn it into the 2004 US version using a 5MB diff file. This was made possible thanks to HDiffPatch. Best Buy, EU original, Sonic PC Collection and Korean versions of SADX are also patchable.

The installer still doesn’t support the new configuration format introduced in the new Mod Manager, and I think it will probably stay that way. However, the new Mod Manager picks up the old format settings generated by the installer so this should be no problem to the players.

At some point in the future the new Mod Manager will handle the Steam conversion, and the installer will no longer be necessary. Some of its features will be implemented in the new Mod Manager or through other means: for example, Guide Mode could be done as a web page with 1-click install links.

Sonic Adventure DC-HD first release

Update 2024/06/29: This tool has been superseded by the Dreamcast Image Builder.

Sonic Adventure DC-HD is a new way to play the Dreamcast version of SA1 on the flycast emulator.

You can play SA1 with the following improvements:

  • The game runs at 60 FPS during gameplay without framerate-related glitches (hopefully).
  • Widescreen hack without model clipping or HUD stretching (some HUD stuff is offset though – this will be fixed eventually).
  • All videos can be skipped by pressing Start, not just the intro.
  • Cheat code to disable all cutscenes.
  • If you cannot run in a straight line with your controller/keyboard, there’s an optional patch for that.
  • Less choppy ocean in Emerald Coast (similar to Dreamcast Conversion for SADX PC).

Sonic Adventure DC-HD is distributed as a patcher program which you use on the original GDI of SA1 (US 1.005, animated title screen) to produce a patched version. It also comes with a cheat file that you need to load in flycast if you want to use the widescreen hack. Follow the instructions on the repo for more details.

This project is a work in progress. Not all features are complete and new features may be added in the future.

SA1 DC-HD has been tested on the standalone version of flycast on Windows and Android. The modified image is only meant to be used on the flycast emulator. 60 FPS and the widescreen hack will not work properly on other emulators or real hardware.

SADX Debug Mode version 2.0

Today I’m releasing an update for the Debug Mode mod that adds a free camera mode.

Using the free camera mode

Press Y on the keyboard to enable free camera. When the free camera mode is enabled, you can use the mouse to move the camera around. The control scheme is similar to the one used in 3D editors in SA Tools.

  • Move the mouse to rotate the camera.
  • Hold Left Shift and move the mouse to move the camera.
  • Hold Control and move the mouse up and down to zoom in and out.
  • Press both Left Shift and Control to lock the camera in place. Press them again to unlock it.
  • Press Numpad + and Numpad – to change camera speed.
  • Press Y again to re-enable vanilla camera. It will remain locked in place until the character touches a camera trigger.

I would like to thank Speeps for providing the source code of an unreleased mod with the the original free camera code, which became the basis for the free camera mode in this mod.

Sonic Adventure VMS + Chao Editor first release

Today I’m releasing a new tool based on the original SA1 DLC editor. This tool has the DLC editor integrated, but its functionality expands to cover more VMS files in SA1. Eventually I would like it to support all of the formats described here, but the highlight for today’s release is the inclusion of a new Chao editor.

Like the original DLC tool, the updated editor will be included in SA Tools, which also have a big update underway.
UPDATE: It’s been released and is now included in SA Tools.
The Chao editor is experimental and will be updated as more information on SA1 Chao data becomes available. There is no documentation for it at the moment, although the most important data should be self explanatory.

The Chao system used in SA1 is the least researched of all Chao games. There are several Chao editors for SADX and SA2, but the only Chao editor for the Dreamcast version of SA1 was Tyro’s VMU editor that requires running on an actual Dreamcast VMU or a VMU emulator, which I found inconvenient. Besides, there have been some updates regarding SA1 Chao data (for example we now have the full SA1 Chao data struct from SADX X360 symbols), and I wanted to make use of that new knowledge to help advance SA1 Chao research. Although several aspects of it are now known better, Tyro’s notes on SA1 Chao data were one of the most important sources of information for developing the editor. I would also like to thank the Chao Island member UltimaNumber, who kindly shared the bits of information I was missing and explained how SA1 Chao data works.

The tool can import all Chao VMS data. Data produced by the Japanese version is also supported:

  • SA1 Chao Garden save file
  • Download Data (Black Market Chao)
  • Chao Adventure (created when you take a Chao out for a walk)
  • Upload Data (created when you hold Y+A as the Chao goes in the transporter)

At the moment saving is only supported for Chao Adventure and Download Data, but you can export selected Chao from the garden save file as Download Data or Chao Adventure data. There’s also an option to export files with headers used by the Japanese version of SA1.

As Chao data is rather complex and the editor is experimental, there may be some bugs, especially with saving data. Also, expect UI changes in the future.

I’d like to thank Speeps for providing a screenshot of Buddy the Chao that I used as an icon for this tool.

Sonic Adventure patches (Better 60 FPS + drift fix)

If you’re interested in hacking Sonic Adventure, you’ve probably seen 60 FPS and widescreen codes for the Dreamcast version floating around. The problem with 60 FPS codes for SA1 is that they make cutscenes run at double speed. Here’s my understanding of why it happens and a solution for version 1.005 (US, animated title screen).

The game uses two values to control framerate and speed: the frame increment (8C754EBC) and the multiplier (8C754EC4) used in physics and other things. The frame increment controls the actual framerate (1 for 60 FPS, 2 for 30 FPS), and the multiplier speeds up or slows down the physics to match it (1 is original speed). The Dreamcast version runs at 30 FPS everywhere except menus and Twinkle Circuit. In 30 FPS mode the frame increment is set to 2, and the multiplier is also set to 2 to speed up the physics to match the reduced framerate. In menus and Twinkle Circuit both values are set to 1, so the game runs at its original speed at full framerate.

This would be all fine, but the problem is the cutscenes. They are programmed in double speed, so the game sets the frame increment to 2 and leaves the multiplier at 1 to get them to work at half speed. This is also the real reason SADX cutscenes are still capped at 30 FPS – updating them would require fixing the timings in all functions used by cutscenes to work properly at 60 FPS, which is a lot more work than simply unlocking the 60 FPS mode in levels like the developers did.

The problem with existing codes is that they don’t account for the above and simply force both values to 1, which causes cutscenes to run at double speed. To fix this, instead of changing the values directly we can do the same thing SADX developers did, and change them depending on what happens in the game. Like in SADX, there is a function that is called to set the required frame increment and multiplier. All we have to do is patch the arguments that are passed for this function when the game loads levels, and leave cutscenes alone. Here are the addresses for version 1.005 (US, animated title screen). Just change the bytes at these addresses from 2 to 1, and the game will set framerate modes like SADX. If you use Demul with Cheat Engine, replace the starting 8C with 2C.

8C04956E
8C04E662
8C054736
8C082AAE
8C09A1D2

Here’s also a code that you can add as a custom cheat for redream. It’s a regular CodeBreaker code so you could use it on other emulators or on real hardware.

cheat=0204956E 420BE501 0204E662 4F22E501 02054736 430BE501 02082AAE 420BE501 0209A1D2 D252E501

There are still two problems remaining with the 60 FPS code:

  • The hardware cannot handle the game at 60 FPS most of the time (sometimes it struggles even at 30 FPS), so you will get a slow motion effect like in older SA1 preview videos. Unfortunately this also affects emulators – for example, at the moment the game does not reach full framerate in redream. There was a similar problem with Sonic Colors, which the Wii can’t handle at 60 FPS, but that was resolved with Dolphin’s overclock feature. Maybe we’ll get that in Dreamcast emulators someday?
    UPDATE: It seems to be perfect on flycast, no slowdown at all.
  • There are glitches that happen when the game runs at 60 FPS. It’s possible that some things in the game were added after the decision to switch to 30 FPS was made, and perhaps they were only tested at 30 FPS. A lot of such glitches appear in SADX. For example, the Leon badnik almost never attacks the player and disappears too fast. There are visual glitches too, for example Tails’ tails are too fast, and the background in the tornado section in Windy Valley loses the multi-layered effect for one layer. A lot of these glitches are fixed in the Dreamcast Conversion mod for the PC version, and it’s also possible to fix them in the Dreamcast version if we really want it. Interestingly some issues that affected DX at 60 FPS don’t affect SA1 at 60 FPS – for example, the Egg Hornet engine sound glitch.

There’s another issue with SA1 on emulators related to not being able to run in a straight line with the keyboard and some controllers. You can fix this by disabling analog interpolation by writing 00 00 00 00 to 8C051278 and 8C051430. CodeBreaker code:

02051278 00000000 02051430 00000000

It’s not an ideal solution but that will do for now. A better fix may show up very soon.

Sonic Adventure DLC tool: GUI version released

I’ve updated the SA Tools with a new version of the SA1 DLC tool that lets you create and edit VMS files for SA1 on the Dreamcast.

Some documentation is available here.

Apart from the GUI making it easier to edit things, this version also fixes several issues with the original tool that made it produce incorrectly aligned VMS files. Now it should be possible to modify and rebuild any of the official DLCs, or create completely new DLCs from scratch.

The tool ended up being a bit more complex than I originally anticipated, and testing it was a challenge. I’d appreciate it if you try it out and let me know on x-hax if you run into any issues. Have fun!

SADX Mod Installer update

I’ve updated the Steam conversion part of SADX Mod Installer with a new UI that tells you what it’s doing and reports all errors right away. If the program crashes while trying to do anything (for example, if there’s an access error because SADX is running or some files in its folder are open in another program), it will let you try again. It also saves logs for both the installer and the Steam conversion tool in SADX folder.

This update is mainly for those who have trouble getting the conversion to succeed and end up with the game missing videos and sounds. The tool should now be able to tell you what’s wrong, though you might still have to reinstall the game from scratch and run the installer again for it to work properly.

This is likely the last feature update for the mod installer. There may be language and maintenance updates in the future, but I won’t be adding any new features or mods to it.