Release

Dreamcast DLC mod release

PkR

The new version of the Dreamcast DLC mod is now out! You can use this mod to play SA1 DC downloadable content in SADX PC, as well as develop your own custom downloads that will work both in the mod and even in the Dreamcast version provided that you convert it using SA Tools first. Also, this version includes Tikal’s challenge, a custom DLC created previously for the Dreamcast version.

Get the mod here or simply update the previous version through the Mod Loader. If you get a “directory not empty” error while updating the mod, just hit cancel and it’ll work fine. I don’t know why it happens.

Here’s an excerpt from readme/release notes:
==CREDITS==
-SonicFreak94 for the code to play the SEGA/Sonic Team voice
-Darksecond for figuring out SA1 DLC and rank data encryption and posting it on ASSEMbler
-Sappharad for providing C# code to decrypt SA1 DLCs and for cracking the integrity check
-Daguar for giving me a hint on where to look for DLC item table
-Exant for making a lightweight “sitting Chao” model for the Tikal DLC
-Moopthehedgehog for the rediscovered Kadomatsu DLC
-TheLegendOfXela for high quality music and sound rips
-LastBreath for beta testing

==CHANGES FROM THE OLD DREAMCAST DLCS MOD==
-The mod has been rewritten from scratch to work more like the original game’s DLC system
-Text strings in all languages used in original DLC content have been preserved
-DLC content can now load in Adventure, Trial or Mission Mode
-Added Tikal’s challenge
-Lighting accuracy updates
-Custom codepage support: add system\dlc\codepage.ini with “FrenchCodepage=….” etc. to make French, Spanish or German strings use a codepage other than 1252
-Famitsu and QUO challenges no longer replace Station Square camera files with their counterparts from the original 1998 release of SA1
-Twinkle Circuit options for characters have been removed – you can now use the “Mercury GP” menu to go to any course with any character
-The “Alternative challenge timer GUI” option has been removed in favor of a more accurate SA1-like timer
-Seasonal DLC options have been rearranged
-Workarounds from the old mod to prevent DLC content from interfering with story progression have not been reimplemented

You can now make your own SA1 Dreamcast DLC

PkR

I’ve added my DLC tool to the SA Tools suite, you can find it in the SA1 folder. It’s a simple command line tool that unpacks VMS files and rebuilds them from source assets and metadata. I want to make a GUI version of it someday, but for now I want to work on something else. The tool and the data should be self explanatory for the most part, and there’s also plenty of documentation in the readme file.

For those who want some juicy details, here’s the layout of SA1 DLC files:

 * VMU HEADER
 * OFFSET	SIZE		TYPE		DESCRIPTION
 * 0		16		string		DLC title
 * 10		32		string		DLC description
 * 30		16		string		Application title
 * 40		2		ushort		Number of icons
 * 42		2		ushort		Animation speed
 * 44		2		ushort		Eyecatch type (unused)
 * 46		2		ushort		CRC (unused)
 * 48		4		uint32		Size without the header
 * 4C		20		null		Reserved
 * 60		32		ushort		Icon palette, 16 colors
 * 80		512		byte		Icon graphics
 * 
 * SECTIONS HEADER (SIZE 64 BYTES) 
 * 280		4		uint32		Pointer to item layout table
 * 284		4		uint32		Item count
 * 288		4		uint32		Pointer to string table
 * 28C		4		uint32		String item count
 * 290		4		uint32		Pointer to PVM
 * 294		4		uint32		Number of PVMs (always 1)
 * 298		4		uint32		Number of textures in the PVM
 * 29C		4		uint32		Pointer to MLT
 * 2A0		4		uint32		Number of MLTs (either 0 or 1)
 * 2A4		4		uint32		Pointer to PRS
 * 2A8		4		uint32		Number of PRSes (always 1)
 * 2AC		4		uint32		Checksum
 * 2B0		16		null		Unused
 * 
 * ITEM LAYOUT TABLE HEADER (SIZE 12 BYTES)
 * 2C0		4		uint32		DLC ID (e.g. 504 in SONICADV_504)
 * 2C4		1		byte		Enable Sonic / Enable Tails
 * 2C5		1		byte		Enable Knuckles / Enable Gamma
 * 2C6		1		byte		Enable Amy / Enable Big
 * 2C7		1		byte		Unknown, probably unused
 * 2C8		4		uint32		Regional lock
 *
 * ITEM LAYOUT TABLE (ARRAY BEGINS AT 0x2CC, ITEM SIZE 30 BYTES)
 *  0		1		uint8		Level ID
 *  1		1		uint8		Act ID
 *  2		1		uint8		Scale X multiplied by 10
 *  3		1		uint8		Scale Y multiplied by 10
 *  4		1		uint8		Scale Z multiplied by 10
 *  5		1		uint8		Rotation speed X
 *  6		1		uint8		Rotation speed Y
 *  7		1		uint8		Rotation speed Z
 *  8		1		sint8		Item type (0: model, -128: sprite, -1: invisible)
 *  9		1		uint8		Texture ID
 *  A		2		ushort		Flags
 *  C		1		uint8		Object ID for collectibles or the number of objects to collect
 *  D		1		byte		Unknown
 *  E		1		uint8		Message ID to show when touching the object
 *  F		1		uint8		Trigger distance
 *  10		1		uint8		Level ID to warp or soundbank ID (8 for MLT, 15 for ADX music)
 *  11		1		uint8		Act ID to warp to or sound/music ID to play
 *  12		2		ushort		Rotation X
 *  14		2		ushort		Rotation Y
 *  16		2		ushort		Rotation Z
 *  18		2		short		Position X
 *  1A		2		short		Position Y
 *  1C		2		short		Position Z
 *
 * DLC OBJECT FLAGS
 *  BIT_0	Unknown
 *  BIT_4	Unknown
 *  BIT_8	Solid
 *  BIT_9	Play sound
 *  BIT_10	Show message
 *  BIT_11	Hide object and disable everything except collision
 *  BIT_12	Warp
 *  BIT_13	Collectible item
 *  BIT_14	Timer item
 *  BIT_15	Starts the challenge
 *
 * REGIONAL LOCK BITS
 *  -1	Disable regional lock
 *   1	Japan
 *   3	US
 *   4	Europe
 *   7	All regions

Sonic Adventure: “Tikal’s challenge” DLC contest!

PkR

This release is for the original Dreamcast game, not SADX PC. A PC version of the challenge will be available at a later date.

Today I’m releasing something a bit special. This is the first fully custom* Dreamcast Sonic Adventure DLC that adds a new challenge without hacking the base game. It’s built like the official SA1 DLCs, and it makes use of SA1’s internal system to add objects and challenges to the game.

Download for emulators or transfer from PC
VMI file download for Dreamcast browser

To stay true to the spirit of official SA1 DLCs I’d like to make this a contest with a “real” (though merely symbolic) prize. To participate, simply record your playthrough of this challenge and share the video. You can play it on an emulator or on a real Dreamcast. The fastest player who beats the challenge in the shortest amount of time will get a free Sonic Adventure DX Steam key from me.

The contest will run until September 23rd, 0:00 (UTC). The deadline may be extended depending on the number of entries.
Submit your results here

To get started, you need to import the file SONICADV_515.VMS or SONICADV_515.DCI to your memory card. On PC you can use a memory card editor (such as redream’s save manager). To play it on hardware you could burn the file to a CD together with Dream Explorer, or use an SD card adapter with DreamShell. If your Dreamcast is connected to the Internet, you can download it from the revived official webpage directly from Sonic Adventure!

This DLC was made using a tool that I’ve been developing during the last several days. Once the tool is released you will be able to make your own DLCs for Sonic Adventure from scratch (within the limits of the game’s DLC system of course)!

*Technically it’s not the first edit of a DLC, but it is the first DLC that adds custom objectives and makes extensive use of the DLC system rather than edits object properties. Huge thanks to Sappharad for figuring out the integrity check for the DLCs, which made this whole thing possible.

Credits:
-Darksecond for figuring out SA1 DLC and rank data encryption and posting it on ASSEMbler
-Sappharad for providing C# code to decrypt SA1 DLCs and for cracking the integrity check
-Daguar for giving me a hint on where to look for DLC item table
-Exant for making a lightweight “sitting Chao” model
-The graphics are based on Sonic Adventure (+DX) assets

Enjoy!