NullDC4Wii - Dreamcast Emulator for Wii

a fork from https://github.com/skmp/nullDCe

TODO (Maybe you can help !)

Simple

• Test current state with every game and report compatibility (see "compatibility" below)
• Create presets for games
• Test 2 player mode on wiimote & gamecube also, please report
• Help me finding regression (NOT bugs or glitch, only regression for now please)
• Comment / Guides / Documentation (WiiBrew Wiki)
• Test and report Fishing Rod/USB Keyboard/Lightgun/Maracas support

Developer (Easy)

• Controller correct layout, for pro pad and for gamecube pad
• User custom Preset
• Player 3/4 Gamecube/Wiimote
• Fishing Rod/USB Keyboard/Lightgun/Maracas support (probably unsupported now)
• Put external config file for controllers (controls.cfg)
• User custom presets file

Developer (Normal)

• Coding routine adjustement for accuracy (FAST/BALANCED/ACCURATE)
• 4/3 support (implemented, need fix on some games like Shenmue)
• Wii U gamepad support like WiiStation ? ( https://github.com/FIX94/libwiidrc )
• Wii U Gamepad, Dualshock 3 and Wii U Pro Controller support ? ( #15 )
• Support for CHD/ELF game file

Developer (Hard)

• Improve gxRend.cpp = main file about specific rendering for Wii
• Splitting gxRend.cpp in multiple files ? (beware this is more tricky than it look)
• Fix alpha/transparent stuff (may be costly in term of performances)
• Table convertion between SH4 Opcodes of SH4 and the WiiPPC ?
• Use LLVM to port code for PowerPC ? (skmp says its not a good idea in this case)
• Full Dynarec implementation (AI seems to know about this)
• WinCE Games support #37

Installation

Put BIOS file and game file

Mandatory BIOS files in SD:/data/

• dc_boot.bin
• dc_flash.bin
• fsca-table.bin (included)

Optional BIOS files in SD:/data/

• dc_flash_wb.bin (this is the dc_flash but already saved)
• syscalls.bin (needed for elf/bin)
• IP.bin (needed for elf/bin)

dc_nvmem.bin
vmu_default.bin

Game file in SD:/discs/ or USB:/dreamcast/

Test with castlevania Resurrection and Sega Tetris to begin with

Put your folders with GDI in this directory. CDI also works

Might work for ISO / BIN / CUE / NRG / MDS

BIN/CUE/ELF, but you probably need IP.bin/syscalls.bin (take IP.TMPL from bootdreams and rename it IP.Bin)

Configuration

General configuration

Check nullDC.cfg at root

Controls

Wiimote :

Dreamcast	Wiimote
A	A
B	B
Y	1
X	2
START	Home
D-PAD	D-PAD
STICK	Nunchuck Stick
L	- (and Nunchuck Z)
R	+

To Exit : - and +

Wiimote (Chuchu Rocket!)

Not implemented yes, but soon ! :)

Dreamcast	Wiimote
A	down & A
B	right & B
Y	up
X	left
START	Home
D-PAD	- no implementation -
STICK	Nunchuck Stick
L	- (and Nunchuck Z)
R	+

To Exit : - and +

Gamecube controller :

Dreamcast	Gamecube
A	A
B	B
Y	Y
X	X
START	START
D-PAD	D-PAD
STICK	STICK
L	L
R	R

To exit : R + L + Z

Gamecube controller (Chuchu Rocket !) :

Not implemented - Need to swap B and X

Dreamcast	Gamecube
A	A
B	X
Y	Y
X	B
START	START
D-PAD	D-PAD
STICK	STICK
L	L
R	R

To exit : R + L + Z

VMU (Memory card)

It seems to be supported, but 1rst you'll need to format the VMU in the bios

Files appears at root of /data/ :

• vmu_save_A1.bin
• vmu_save_A2.bin

Status (10/06/2026)

launch on dolphin an real Wii with FPS between 8 and 50 Fps
game selector implemented
2 players controler implemented
Games tested : See compatibility

Wii Dynarec has been improved & completed by AI. Compile but doesn't run (Black Screen). See /archive folder

https://www.youtube.com/watch?v=Ug8V2XXO52Q

Compatibility

https://wiibrew.org/wiki/NullDC4Wii/Compatibility

Presets

🧮 Calculation Accuracy Preset

Mode	Description
FAST	Maximum FPS (higher frame rate), less loading times
BALANCED	Good balance between speed and accuracy
ACCURATE (default)	Closest behavior to original hardware

If you experience Freeze in some heavy games like Shenmue, put FAST or BALANCED. BALANCED may be the default setting in future versions

If you experience various bugs (example that may happens : weird AI controled NPC) put ACCURATE

---

🖼️ Graphics Preset

Mode	Settings	Best platform
LOW (default from a0.06 to a0.09)	GX_NEAR · lod_bias 0.0f · GX_DISABLE	Wii
NORMAL (default from a0.10)	GX_LINEAR · lod_bias 0.0f · GX_DISABLE	Wii
HIGH	GX_LINEAR · lod_bias -0.5f · GX_ENABLE · Anisotropic x2	Wii U
EXTRA	GX_LINEAR · lod_bias -1.0f (may need to adjust to -0.75) · GX_ENABLE · Anisotropic x4	Wii U

While the emulator is still in alpha, the visual difference is limited for now.

• Use LOW for 2D and heavy 3D games
• Use NORMAL for other games

Mode (4BPP/8BPP)	Settings	Rendering
I4_STUB/I8_STUB	Dummy algorythm	Some element doesn't display at all, for max FPS
I4 (FAST)/I8 (FAST)	Basic algorythm	Display in grey Scale (Use for debug)
CI4 (FAST)/CI8 (FAST)	Basic algorythm	Display mostly correctly (consume a bit of FPS on some games)
CI4 (NORMAL)/CI8 (NORMAL)	Advanced algorythm for CI4/CI8	Should display better
RGB565	Most advanced algorythm	Can have massive FPS dropdown (1 FPS) on some games

Cache setting (starting alpha 0.21)

Mode	Settings	Rendering
CACHE_VERY_FAST	skmp original algorythm (magic numbers). Very fast but buggy	Max FPS
CACHE_FAST	Broken for now, generally worse than VERY_FAST and NORMAL	??? FPS
CACHE_NORMAL	Best accuracy. Display mostly correctly	Mid FPS
CACHE_QUALITY	Best accuracy. Display mostly correctly	Mid FPS
CACHE_EXTRA	Redraw every frame. Accurate (Only for dev & Debug)	Low FPS

ADVANCED_ALPHA

Mode	Settings	Rendering
NO	basic alpha threathment	Not accurate
YES (default starting alpha 0.30)	additionnal alpha threatment	Near perfect

PPZ_WRITE : PER POLYGON Z WRITE

Mode	Settings	Rendering
NO	No Per Polygon Z Write	More compatible
YES (default)	Per Polygon Z Write	More accurate

Try putting NO if you experience troubles, with HUD for example.

See Compatiblity guide for hints depending of the games

For Developpers :

Compilation Process (Windows)

0/ Download/clone source code

1/ Install devkitpro/devkitPPC

https://wiibrew.org/wiki/DevkitPPC

Just tick PPC (not ARM, x86, etc).

See this issue : #13

2/ Launch MSys2 terminal

Devkitpro has it's own UNIX terminal, by default it's located here :
C:\devkitPro\msys2\usr\bin\mintty.exe

3/ Install additional development packages :

pacman -Syu # updates MSYS2 and package database
pacman -S wii-dev

4/ PATH & System variable configuration (Windows)

PATH

In windows variable environnement add C:\devkitPro\devkitPPC\bin to Uservariable PATH

UPDATE MARCH 2026 : This folder seems to be needed also for elf2dol : C:\devkitPro\tools\bin

System variables

Modify these system variable

DEVKITPPC : C:\devkitPro\devkitPPC
DEVKITPRO : C:\devkitPro\

Strongly advise you to completly reboot Windows after that (not just relaunching CMD)

5/ launch wii/vs_make.bat in a standard CMD windows terminal

Correct errors if they are some errors

Use dollz3

dollz3 is a compress tool for *.dol files, and it is in the original "vs_make.bat" file, but it seems not to work

https://wiibrew.org/wiki/Dollz

Compilation Process (Linux & Mac)

It should work for Linux & Mac with similar process

Leaving this link for now :

https://wiibrew.org/wiki/DevkitPPC

Dolphin

Activate :

• SD Card
• Display FPS
• Advanced > Debug > Texture Format Overlay

Ressources

Dreamcast Emulators

NullDC https://code.google.com/archive/p/nulldc/source/default/source
NullDC (github) https://github.com/skmp/nullDCe
NullDC for PSP : https://github.com/PSP-Archive/nulldce-psp
NullDC for Xbox360 https://github.com/gligli/nulldc-360
Reicast : https://github.com/skmp/reicast-emulator
Flycast : https://github.com/flyinghead/flycast
Deecy : https://github.com/Senryoku/Deecy

Devkitpro

Main website : https://devkitpro.org
​GitHub : https://github.com/devkitPro
Installer (releases) : https://github.com/devkitPro/installer/releases
Wii ​Examples : https://github.com/devkitPro/wii-examples

libOGC

GitHub (Wii/GameCube system librairy) : https://github.com/devkitPro/libogc

Emulators​

Dolphin Official Website : https://dolphin-emu.org
GitHub (for timings Gekko/CPU) : https://github.com/dolphin-emu/dolphin

Wiibrew Wiki

Emulation Page : https://wiibrew.org/wiki/Emulation
Homebrew tutorials : https://wiibrew.org/wiki/Main_Page

Credits

• skmp (original NullDC creator)
• NullDC contributors
• Joseph Jordan - libiso
• Xale00 (also know as Benoit Adam) - 2026 recompilation
• gligli (Xbox 360 port)
• Xeihro (Xiro28 PSP Port)
• Flyinghead/Flycast Team
• AI because this project would have never existed otherwise lol
• Probably Reicast Team also who knows
• Welcome to the IA-age guys and good luck everyone.

All together, let's Cast the Dream.

Special thanks

• skmp because he's the god
• Senryoku, develloper of Deecy emulator
• All testers and all futur testers
• People actually helping me on the wiibrew wiki

Special no thanks

• To all people not believing in this project
• People constantly critisizing the fact AI is used in this project, being condescending or worse. Please Grow up.