Genesis3D Native Linux

A source-available, native 64-bit Linux runtime for the Genesis3D 1.x engine lineage.

This repository descends from the RealityFactory/Genesis3D tree. It contains Genesis3D 1.1 code released in 1999, subsequent inherited source snapshots, and Kadaken's 2026 Linux port. The Linux port was developed by Kadaken with assistance from Gemini and Codex; no outside community contributors to the port are claimed. Kadaken did not create the original engine and is not affiliated with or endorsed by Eclipse Entertainment, WildTangent, Reality Factory, or the owners of games made with Genesis3D.

Current scope

The native target is an engine runtime and validation sandbox, not a complete game or a finished replacement for every historical Genesis3D SDK tool.

Verified on one Fedora KDE system with AMD/Mesa:

• native x86-64 C/C++ build;
• SDL2-owned X11/XWayland window and input;
• OpenGL BSP geometry, textures, baked lightmaps, PVS selection, and translucent ordering, including transformed door/platform submodels;
• ACT/BODY loading, complete skeletal scale propagation, material alpha, fixed-step animation playback, and a generic first-person actor pass;
• runtime lightmap updates;
• swept-hull BSP collision, gravity, jumping, stairs, slopes, wall sliding, and ceiling rejection in deterministic real-map fixtures;
• 60 and 120 FPS presentation targets on the tested machine; and
• normal SIGINT/SIGTERM teardown under the documented sanitizer checks; and
• a versioned in-process C renderer API exposed by libgenesis3d_render.so.

Known limitations and the exact evidence boundary are documented in Reports/VERIFICATION_SCOPE.md. In particular, the project has not established exact pixel equivalence with the original Windows renderer, broad GPU/distribution support, or completion of every legacy engine subsystem.

Licence and release status

The covered source is distributed under the Genesis3D Public License v1.01. Read the complete, controlling text in g3dlicense.txt before using, modifying, or redistributing this code. This is a custom source-available licence; the project does not represent it as an OSI-approved licence.

Important obligations include publishing covered engine modifications under the same terms, documenting modifications, retaining required notices, and using the original Genesis3D logo as specified by the licence. The native validation executable does not yet implement the required original animated startup logo. Therefore this repository currently publishes source only and does not offer a redistributable binary release. Do not redistribute a compiled product, demo, or application from this branch without independently satisfying every licence condition.

See LICENSE, LEGAL.md, NOTICE.md, and MODIFICATIONS.md for discoverability, provenance, and release safeguards. Those summaries do not replace the controlling licence.

Assets are not included

No commercial game, map, actor, music, voice, or other legacy game asset is distributed in this repository. You must provide compatible assets that you are legally entitled to use.

At runtime, the engine selects the alphabetically first readable compiled level from Assets/Maps/ (.bsp or .gbsp) and requires at least one readable .act file in Assets/Actors/. Point GENESIS3D_PROJECT_ROOT at a directory containing that Assets/ layout. If the variable is unset, the development harness uses ./Assets when present and otherwise checks the legacy local ./PurificationWorkspace/Assets layout. Neither directory is tracked.

Build

Fedora dependencies:

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

Ubuntu/Debian dependencies:

sudo apt install build-essential cmake pkg-config libgl1-mesa-dev \
  libglu1-mesa-dev libx11-dev libsdl2-dev libopenal-dev

Configure and compile out of tree:

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

Compilation and the synthetic CTest fixtures require no proprietary assets. The standalone map/actor harness requires compatible runtime assets.

Historical engine API driver

The build also produces libOglDrv.so, the inherited OpenGL DRV_Driver backend with an SDL host. An application initializes SDL video, sets its GL framebuffer attributes, creates one SDL_WINDOW_OPENGL window, and passes that SDL_Window * as the opaque window argument to geEngine_Create. Pass the directory containing libOglDrv.so as DriverDirectory. Select an enumerated driver mode before calling the historical frame API.

The application owns the window and event pump. The driver owns the OpenGL context and releases it on driver shutdown without destroying the window. It supports one active legacy driver context per process; concurrent legacy engine instances and mixing it with the high-level renderer are unverified. The WindowMode entry uses the caller's current drawable dimensions.

Asset-free tests run geEngine_Create, driver selection, world/texture creation, BeginFrame/RenderWorld/EndFrame, pixel readback, and teardown. One test uses a public empty world plus a textured polygon; another generates a GBSP with a root face and a half-intensity lightmap. Both pass under Xvfb with Mesa llvmpipe and ASan/UBSan. This establishes the tested legacy frame paths, not hardware performance or completion of all historical renderer features. See the legacy driver report.

Driver ABI 100.4 requires rebuilding engine and driver together. Fullscreen defaults to SDL desktop fullscreen; exclusive display mode switching is only available to driver-hook callers setting DRV_HOOK_EXCLUSIVE_FULLSCREEN. The standard engine initializer leaves that flag clear. See the SDL window policy tests.

Install xorg-x11-server-Xvfb and xorg-x11-xauth on Fedora (or xvfb and xauth on Debian/Ubuntu) to register and run the isolated graphics tests:

ctest --test-dir build --output-on-failure

Native render library

The CMake build produces both the original genesis3d_linux validation executable and libgenesis3d_render.so.1. Applications should include Engine/LinuxRender.h and link the genesis3d_render CMake target.

The versioned C ABI provides opaque runtime ownership, exact-map loading, generic entity queries, multi-actor ownership, full Euler transforms, motion/scale selection, and application-designated first-person view actors, BSP submodel lookup and authored motion sampling, per-model render visibility, SDL input polling, fixed-step BSP player collision and bounded map-level movement coefficients, bounded world-material inspection/replacement, explicit camera submission, simulation advancement, protected world-space and 2D overlay callbacks, and single-frame rendering. The world callback executes after BSP geometry with camera matrices active; the renderer restores its OpenGL state and matrices before continuing. Dynamic surface decoding and all other game policy remain outside the engine target.

The historical geSound_* API uses an OpenAL backend on Linux. It supports looping, pitch, per-source gain/pan, master gain, deterministic source cleanup, and headless tests through OpenAL Soft's null output driver. The legacy geSound_GetDSound escape hatch returns null because DirectSound objects do not exist on Linux; clients must treat that optional platform handle accordingly.

The actor subsystem also supports a new, explicitly versioned BODY 0x00F2 format with up to four normalized skinning influences per vertex. Historical 0x00F1 actors remain on their unchanged rigid fast path. The standalone gltf2act target converts bounded glTF 2.0/GLB skeletons, weighted triangle meshes, embedded PNG base-colour materials, and linear animation channels into verified ACT containers; see the implementation and remaining gates.

Visible runtimes request a four-sample multisampled framebuffer and enable OpenGL multisampling when the driver grants it. Window creation automatically retries without multisampling on systems that cannot provide that format, so anti-aliasing improves supported hardware without becoming a startup gate. World material textures also receive generated mip chains, trilinear minification, and up to 8x anisotropic filtering when supported. Runtime material replacement regenerates the mip chain so animated surfaces never sample stale lower levels. Lightmaps retain their original linear sampling and update path.

The intended per-frame order is:

1. geLinuxRender_PollInput;
2. application-owned fixed-step state/physics updates, optionally using geLinuxRender_StepPlayer;
3. geLinuxRender_SetCamera;
4. geLinuxRender_AdvanceSimulation; and
5. geLinuxRender_RenderFrame.

Create the runtime with Headless = 1 for entity, collision, and lifecycle tests that must not initialize SDL/OpenGL or capture input.

Development launch

Headless or agent-run checks must never capture the desktop's keyboard or mouse:

GENESIS3D_NO_INPUT_CAPTURE=1 \
GENESIS3D_PROJECT_ROOT=/path/to/compatible-assets \
./build/genesis3d_linux

For a person intentionally testing input on their own desktop:

GENESIS3D_ENABLE_INPUT_CAPTURE=1 \
GENESIS3D_PROJECT_ROOT=/path/to/compatible-assets \
./build/genesis3d_linux

Controls are W/A/S/D or arrow keys to move, Shift to sprint, Space to jump, mouse motion to look, the mouse wheel to emit neutral next/previous selection edges, and Escape to exit. Interactive mode captures the mouse only while the engine window has focus and releases it when focus is lost.

Contributing

Issues and pull requests are welcome. Start with CONTRIBUTING.md and the community engine roadmap. Contributions must be original or properly licensed, must not include commercial game data, and are subject to the Contributor Grant in the Genesis3D Public License.

Historical material

Some excluded Windows driver/project files are retained only as historical reference and are not part of the native build. Files carrying restrictive third-party SDK/header notices that were unnecessary for the Linux target have been removed from the current branch. Their former presence in inherited Git history is disclosed in LEGAL.md.