OPEN-SOURCE ENGINE
Under the hood.
This web client uses the xu4 engine, licensed under GNU GPL version 2 or later.
Engine license · Contributors · Web build instructions · Source file list
The corresponding engine source and included engine assets for this build are available at the paths in that list. Original Ultima IV DOS data is not included. The graphics-only VGA overlay is included with original author credits and redistribution terms. The soundtrack supplied with xu4 is included; alternate soundtrack packs are not distributed. Music payloads are not copied into the downloadable source snapshot.
The library also includes the OpenU5 web source port under GPL-3.0. License · Notice · Ultimatum integration. Its exact pinned corresponding source is included; original Ultima V game data is not.
The library also includes the experimental Duke Nukem II web port through RigelEngine under GPL-2.0. License · Third-party notices · Ultimatum integration. Its pinned corresponding source and patch stack are included; original Duke Nukem II game data is not.
The test library also includes an experimental Commander Keen 4 web port through Commander Genius under the GPL. License · Third-party notices · Ultimatum integration. Its pinned corresponding source and patch stack are included; original Commander Keen game data is not.