Ocarina of Time for Dreamcast

AI Disclosure

The original author of the port, Bruce, used various LLMs to: bootstrap this port, create the filesystem interface and produce the PowerVR fast3d interpreter it uses. I have since used LLMs to replace the software audio mixing, rework the build system and update the documentation to accurately reflect those updates. I am not the original author of this project, I have just offered to clean it up for him and present it for people to do what they see fit with it.

What is it

A native Sega Dreamcast port of The Legend of Zelda: Ocarina of Time, built from the ZeldaRET decompilation. The game code is compiled for the SH4 with KallistiOS; the N64's RSP/RDP graphics are replaced by a display-list interpreter that draws on the PowerVR, and the game's music and sound effects are played through the AICA's hardware voices.

The whole build runs with your host and Dreamcast toolchain. There is no N64 build step and no MIPS toolchain: the layout metadata the port needs is derived from the ROM.

No game data is included. You need your own copy of the game. Only the GameCube Master Quest debug ROM (gc-eu-mq-dbg) is supported at the moment.

Requirements

• KallistiOS 2.2 or newer, with the sh4zam library installed from kos-ports
• clang or gcc, libxml2 headers, python3
• GNU make 3.82 or newer (macOS: brew install make and use gmake)
• mkdcdisc, only for making .cdi disc images

Building

# once: python deps (scipy is required for the audio transcode)
python3 -m venv .venv && .venv/bin/pip install -U pip -r requirements.txt

# your ROM (.z64, .n64 or .v64 all work)
cp /path/to/your/rom.z64 baseroms/gc-eu-mq-dbg/baserom.z64

source /opt/toolchains/dc/kos/environ.sh

make -f Makefile.dc extract    # decompress the ROM, extract assets, generate build inputs (~30s)
make -f Makefile.dc assets     # compile the asset segments for the Dreamcast (a few minutes)
make -j $(nproc) -f Makefile.dc        # build zelda.elf

extract builds the handful of host tools it needs with your C compiler the first time it runs. Makefile.dc has no dependency tracking, so run make -f Makefile.dc clean after editing source files.

The result is zelda.elf plus the runtime asset files in assets_dc/.

Running

The game looks for assets_dc/ on /pc (dcload's host filesystem) first and then on /cd, so the same zelda.elf runs either way.

Over dcload, from the repository root so /pc/assets_dc/ resolves:

sudo dc-tool-ip -t <dreamcast-ip> -x zelda.elf -c ./

From a disc image (needs mkdcdisc on your PATH):

make -f Makefile.dc cdi        # oot.cdi: padded, for burning to CD-R
make -f Makefile.dc cdi-ode    # oot-ode.cdi: unpadded, for ODEs

Both images contain zelda.elf as the boot binary, assets_dc/ and ocarina.ico. make -f Makefile.dc clean-disc removes them.

Saving

Saves go to the first VMU found, as one file oot.rec (66 blocks) with the ocarina icon. Without a VMU the game still runs and saves last for the session only. A VMU inserted after boot is picked up on the next save.

Options

variable	default	effect
DEBUG_FEATURES	0	1 builds the debug version (map select on boot, debug camera, on-screen debug text)
LTO	1	0 disables link-time optimisation
DC_VERSION	gc-eu-mq-dbg	ROM version directory under baseroms/

Example: make -f Makefile.dc DEBUG_FEATURES=1.

Layout

• src/dreamcast/, src/linux/: the Dreamcast and port platform layer (renderer, file loading, audio glue)
• src/audio/internal/aica_synth.c, tools/aica/: the AICA audio driver and its build-time sample transcoder
• pc_tools/: the host-only build pipeline (dc_extract.py, dc_meta.py, dc_assets.py)
• Makefile.dc: the Dreamcast build
• everything else (src/, include/, assets/, spec/, tools/) is the decompilation, trimmed to what this build uses

Credits

This port would not exist without the work of the ZeldaRET team and contributors on the Ocarina of Time decompilation. See the upstream repository for the decompilation project itself, its documentation and its contributors.