Reality Factory, native Linux

A native 64-bit Linux port of the Reality Factory runtime, upstream 0.76.1. Reality Factory is the game creation kit built on the Genesis3D engine, last released for Windows in 2009.

This is not finished. It builds, it links, it opens a window, it renders. It does not yet run a game end to end. Everything below is measured, and the gaps are listed as plainly as the wins.

What works

• Native x86-64 build on current Fedora and Ubuntu. No Windows headers, no _WIN32 conditionals left in gameplay files.
• SDL2 host: window, input and joystick, replacing the Win32 message loop and the legacy DirectInput joystick boundary.
• POSIX compatibility boundary for the platform calls the original assumed.
• The virtual file system, menu system, GIF decoding, entity schemas and actor loading all pass their fixtures.
• Reaches stage 4 and completes one frame, with a queued quit, clean teardown and exit 0, sanitizer clean under ASan and UBSan.

What does not work yet

Read FINDINGS_OUTSIDE_SCOPE.md for the full record. The headline gaps:

• Stage 5 stops on tick 1 at CWeapon.cpp:1343, WeaponD[CurrentWeapon] with CurrentWeapon = -1, before first-weapon assignment. Source review points to a missing previous-weapon guard. Not yet fixed.
• No interactive launch. The human launch path has no built-in-panel selector and no relative-mouse capture, so ESC-to-menu and capture release are untested.
• Thread safety unproven. CCommonData::TimerFunction reads HasFocus and TimeCounter from the periodic timer thread without synchronisation against main-thread access. ASan and UBSan do not establish race freedom; this needs ThreadSanitizer before anyone claims interactive timing is safe.
• No visual equivalence testing against the original Windows renderer.
• Test suites sit at 39 of 41 Release, 40 of 42 sanitized, with stages 4 and 5 parked.

Build

Fedora:

sudo dnf install gcc gcc-c++ cmake make pkgconf-pkg-config \
  mesa-libGL-devel libX11-devel SDL2-devel freeimage-devel

Ubuntu and Debian:

sudo apt install build-essential cmake pkg-config libgl1-mesa-dev \
  libx11-dev libsdl2-dev libfreeimage-dev

Then:

cmake -S . -B build
cmake --build build --parallel

Compiling needs no game assets. Running one does, and you must supply content you are entitled to use. None is distributed here.

Layout

• upstream/ — the Reality Factory source with port changes. See upstream/PROVENANCE.md and MODIFICATIONS.md.
• adapters/ — the Linux platform layer. Kept out of gameplay files on purpose.
• tests/ — fixtures, including neutral content fixtures.
• tools/ — build-time generators and the frame-clock audit.

Licence, and one clause that matters

Reality Factory is distributed under an MIT-form grant by Ralph Deane, 2002, with one added condition, quoted in full:

It is prohibited to use Reality Factory for games that intentionally propagate genocide against a certain group, race, nation or religion existing in today's real world.

That clause is part of the licence and it travels with this port. Read upstream/license.txt before using, modifying or redistributing. Porting the runtime is unaffected by it; what you build with the runtime is not.

Help is wanted

The gaps above are the work. Stage 5's weapon guard is the obvious next fix, interactive input is the obvious next feature, and the thread race needs somebody with ThreadSanitizer and patience. Open an issue, open a pull request, or just tell us what broke on hardware we do not have.

Reality Factory was kept alive by its community for two decades after its last official release. This is an attempt to move it somewhere it has never run.

Linux port by Kadaken, 2026. Upstream work is not ours and is not claimed.