Ecco the Dolphin: Defender of the Future: Recompiled (Dreamcast)

A native PC port of Ecco the Dolphin: Defender of the Future (Dreamcast, Europe, Appaloosa Interactive / Sega 2000), built with dreamcomp. The game's SH-4 code is statically recompiled to C++ ahead of time, and the Dreamcast's graphics, sound and disc hardware run as native code around it. It is not an emulator running the original binary.

You need your own copy of the game. This repository contains no game code or data. The port reads your disc image at run time and refuses any release other than the one it was built from: Europe, MK-5103350 V1.003, boot file 0.BIN, SHA-1 e6b20996…e921d264c0.

Status

The whole game can be played through on Linux: intro, menus, all levels, music and effects, and memory-card saves. Checked by playing it end to end and with scripted runs that compare the recompiled code against the engine's SH-4 interpreter.

Platform	Linux x64 (CachyOS, g++ 16, Vulkan, Wayland). Windows and macOS untested for this port
Disc	Europe only (MK-5103350). The USA and Japanese releases are different binaries
Recompiled code	17,574 functions, 0 untranslated calls over menus and gameplay

Features

• Widescreen without stretching (Aspect ratio: Expanded, up to 21:9). The field of view gets wider and the vertical view stays the same. This is done through the game's own projection function, not Flycast's cheat, which changes tan() everywhere in the game. The health and air bars keep their 4:3 shape. The menu cursor is fixed up for wide shapes
• Internal resolution up to 8x (scale)
• High refresh rate: frames blended between game frames on displays above 60 Hz (fps). The game logic stays at its own rate
• Accurate translucency: see-through surfaces are sorted per triangle, so above-water rock no longer shows through the sea surface from below
• Saves to a per-user virtual memory card; rumble; keyboard and gamepad, rebindable in game
• Texture dumping and replacement packs, file mods (dreamcomp docs/TEXTURE-PACKS.md, docs/MODS.md)

Building (Linux)

Needs cmake, ninja, a C++20 compiler, Python 3, SDL3, the Vulkan headers and glslc. On Arch or CachyOS:

sudo pacman -S --needed cmake ninja sdl3 vulkan-headers vulkan-icd-loader shaderc python

The port builds inside a dreamcomp checkout. The Linux fixes and the engine changes this port needs are on the linux-ecco branch of the fork:

git clone -b linux-ecco --recurse-submodules https://github.com/cherryduck/dreamcomp
cd dreamcomp
python3 -m venv .venv && .venv/bin/pip install -e "engine/tools/dcdisc[test]" pillow
git clone https://github.com/cherryduck/ecco-the-dolphin-defender-of-the-future-recomp \
    ports/ecco-the-dolphin-defender-of-the-future-recomp

P=ports/ecco-the-dolphin-defender-of-the-future-recomp
.venv/bin/python tools/dc.py setup $P --disc "/path/to/Ecco the Dolphin - Defender of the Future (Europe) (En,Fr,De,Es).cue"
.venv/bin/python tools/dc.py build $P
.venv/bin/python tools/dc.py run   $P --window

setup checks the disc and extracts only the boot executable, which the recompiler needs at build time. Everything else is read from the image while you play. Accepted formats are Redump .cue/.bin, .gdi and .chd. The generated code is split into one part per CPU thread (DREAM_GEN_SHARDS), so a fresh build takes about a minute on a 32-thread machine.

The executable ends up at $P/build/game/ecco-the-dolphin-defender-of-the-future-recomp. Started with no arguments, it opens with your saved settings.

Playing

Keyboard	arrows = d-pad, Z X A S = A B X Y, Enter = Start, Q W = triggers
Menu	Escape or the pad's Select: settings, controls, quit
Keys	F1 HUD editor, F2 HUD list, F10 FPS counter, F11 frame capture, F12 screenshot
Settings	~/.config/dreamcomp/ecco/settings.ini (edited by the in-game menu)
Memory card	~/.config/dreamcomp/ecco/vmu_a1.bin

When you start the game, Select a Game lists your existing saves under New Game. The game refuses to create a second save with initials it already has, so pick the existing one.

Known limitations

• Widescreen is limited to 21:9; wider shapes have not been checked
• About 1 % of the screen can still have see-through layers in the wrong order where triangles really pass through each other; the console sorts per pixel
• In fast turns at high refresh rates, some in-between frames are skipped instead of tearing, so the motion there briefly drops back to the game's own rate
• The frame-wait idle skip used by other dreamcomp ports does not apply to this game's library (Kamui2), so the game thread busy-waits for vblank

Environment switches for A/B comparisons: DREAM_STRIP_SORT=1 (old per-strip translucency sort), DREAMCOMP_NO_HUD_FIX=1 (stretched HUD).

How it was made

docs/GAME-INTERNALS.md records what was measured about the game and how: the CodeWarrior link address, the Katana stub relocations, the projection builder, the HUD layers and the menu cursor. docs/PLAN.md has the phases, decisions and verified checkpoints, and docs/findings/phase-00.md the disc survey. The engine changes are listed in dreamcomp's docs/engine-changes.md, and the traps found along the way are entries T26–T31 in its playbook.

Credits

• Ecco the Dolphin: Defender of the Future © 2000 Sega, developed by Appaloosa Interactive. This project is not affiliated with Sega or Appaloosa.
• dreamcomp (danielgomesvieira2000), built on dream-recomp (phobos665), which draws on Flycast.
• The widescreen projection was located from Flycast's widescreen cheat table entry for MK-5103350.

AI use

Developed with AI assistance (Claude), following dreamcomp's workflow; see dreamcomp's README.

Licence

GPL-2.0.