# OpenIGI: WebGPU independent reimplementation of Project IGI > Source: > Published: 2026-11-12 17:08:11+00:00 **An open-source engine for *Project I.G.I.: I'm Going In* (2000) and *I.G.I. 2: Covert Strike* (2003).** OpenIGI is a clean-room reimplementation of Innerloop Studios' engine, written in C# on .NET 10. It runs the original games from your own retail installation. The original missions, scripts and AI play as they did in 2000, and a modern renderer, launcher and modding platform are built around them. [openigi.com](https://openigi.com) · [Releases](https://github.com/OpenIGI/OpenIGI/releases) · [Modding guide](https://github.com/OpenIGI/OpenIGI/blob/master/sdk/README.md) · [Contributing](https://github.com/OpenIGI/OpenIGI/blob/master/CONTRIBUTING.md) **You need your own copy of the game.** OpenIGI contains no game assets and none of the original code. Every texture, model, sound and script comes from the installation you point it at. - **Faithful to the original.** The game's own QVM scripts run on a reimplemented interpreter, over a deterministic 30 Hz simulation that reproduces the original's timing, AI perception, weapon tables and mission flow. A`vanilla` mode reproduces the original picture and is held pixel for pixel as a regression gate. - **A modern renderer.** Deferred HDR rendering with cascaded shadows, real-time global illumination, volumetric fog, screen-space reflections, temporal upscaling and hardware ray tracing on capable GPUs. NVIDIA DLSS (Super Resolution, DLAA, Ray Reconstruction and Frame Generation) and Reflex are offered as an optional download. - **Direct3D 12, Vulkan and WebGPU.** One renderer runs on all three. It runs natively on Windows, Linux and macOS, and in the browser. - **A launcher.** It finds your games, installs and updates OpenIGI on the stable or beta channel, and manages content packs and mods. - **Moddable.** You can replace art by dropping files in a folder, install content packs with a load order, or write code mods in C# against a versioned API, published through a community index and built from source. | | Project I.G.I. | I.G.I. 2 | |---|---|---| | Campaign | All 14 missions | All 19 missions load and play; in development | | Released builds | Yes | Not yet, run from source | | Browser | First 6 missions, original graphics | No | | Multiplayer | No | No | | Platform | Graphics API | Hardware ray tracing | |---|---|---| | Windows 10/11 x64 | Direct3D 12 (default), Vulkan | Yes, on DXR 1.1 / RTX- and RDNA2-class GPUs | | Linux x64 | Vulkan | Yes, on RTX- and RDNA2-class GPUs | | macOS 13+ (Apple silicon) | Vulkan through MoltenVK, included | No: shadows, reflections and GI use their screen-space and shadow-map forms | | Browser | WebGPU | No | **Desktop.** Install the launcher from [openigi.com](https://openigi.com). On Windows that's a download. On macOS and Linux run: ``` curl -fsSL https://openigi.com/install.sh | bash ``` The launcher looks for your game installations, or you can point it at them in Settings. It installs OpenIGI and keeps it up to date. Switch to the **beta** channel in Settings for builds from the development branch. **Browser.** Open [openigi.com](https://openigi.com) in a browser with WebGPU and choose your Project I.G.I. folder. The files are read on your machine and never uploaded. You need the **.NET 10 SDK** (the version is pinned in [`global.json`](https://github.com/OpenIGI/OpenIGI/blob/master/global.json)). ``` dotnet build -c Release OpenIGI.slnx dotnet test -c Release OpenIGI.slnx ``` Tests that need retail data read `IGI_GAME_PATH` and `IGI2_GAME_PATH`, and skip themselves when those are unset. A checkout with no game data still builds and tests clean. Some optional native components are fetched into `third-party/` rather than committed: | Script | Needed for | |---|---| | `tools/fetch-wgpu-native.ps1` | The desktop WebGPU backend | | `tools/fetch-streamline.ps1` | DLSS and Reflex in development builds | | `tools/fetch-dxc.ps1` | Regenerating the committed DXIL shaders | Copy the build into the game folder and run it there, or tell it where the game is: ``` export IGI_GAME_PATH="/path/to/Project IGI" # PowerShell: $env:IGI_GAME_PATH = "C:\Games\Project IGI" export IGI2_GAME_PATH="/path/to/IGI 2" dotnet run -c Release --project apps/OpenIGI.Desktop -- -title igi1 ``` | Option | Effect | |---|---| | `-title igi1\|igi2` | Which game to run | | `-game ` | The installation to read, ahead of the environment variables | | `-mission ` | Start in a mission, skipping the menus | | `-window` ,`-size WxH` ,`-fullscreen` | Window mode. Borderless is the default | | `-difficulty easy\|normal\|hard` | Difficulty | | `-vanilla` | The original menus, picture, pacing and audio | | `-content ` | Load a content pack folder | | `+` | Run a console command at startup, for example `+gfx_preset ultra` | `-help` lists every option, including the capture and camera tools used in development. The graphics presets are `vanilla`, `enhanced`, `high` and `ultra`. Each one sets the renderer's variables together; every setting can also be changed on its own in the settings pages or the console (`` ` ``). The graphics API is chosen automatically: Direct3D 12 on Windows (when the GPU supports shader model 6.6), Vulkan elsewhere. Override it with `r_renderer`, or press **F10** to switch APIs while the game runs. DLSS and Reflex need an NVIDIA RTX GPU on Windows. Install them from the launcher's Content page (**NVIDIA DLSS**). Without them the engine's own temporal upscaler runs. Settings are saved to `settings.cfg` beside the executable if one exists there, otherwise to your user profile: `%APPDATA%\OpenIGI`, `~/.config/OpenIGI` or `~/Library/Application Support/OpenIGI`. - **Replace a file.** Put it under`/overrides/` at the path it has in the game, for example`overrides/common/textures/000_04_1.tex` . A`.res` archive there works too. The`overrides` console command reloads the folder, and**F8** toggles it. - **Content packs.** These are folders of replacement art with a load order, installed and ordered from the launcher's Content page. The tools to build one from your own installation, such as an AI-upscaled texture pack, are`tools/texture-forge` and`tools/OpenIGI.Tools.ResExtract` . - **Mods.** A mod can ship files that stand in for the game's, whole new missions and campaigns, C# code, and shader passes over the picture, before the tone map or after it. Its code is one`Configure` that says, top to bottom, what it changes through a builder: settings, level systems, task types, script constants, the games' events and HUD overlays. A save records the mods it was made with, and a mod's tests are built with the same SDK against a harness that configures it as the game does. Start one with the template (`--kind code` ,`data` or`shader` ): ``` dotnet new install OpenIGI.Modding.Templates dotnet new openigi-mod -n MyMod --modId my-mod ``` Mods are published through a community index and built by its CI from a pinned commit of their public source, never from an author's binaries. The launcher's Mods page installs them. See the [modding guide](https://github.com/OpenIGI/OpenIGI/blob/master/sdk/README.md) . ``` apps/ OpenIGI.Desktop (the game), OpenIGI.Launcher, OpenIGI.Web (the browser build) src/ Core/ primitives, settings, retail file formats, the QVM interpreter, release manifests Engine/ the game host and frame loop, virtual file system, mod API and loader Game/ gameplay shared by both games, each game's own gameplay and presentation, the menus Rendering/ the renderer, its hardware interface, the D3D12/Vulkan/WebGPU backends, shaders, DLSS Audio/ OpenAL and Web Audio Platform/ windowing and input for desktop and browser UI/ the UI framework used by the menus and the launcher sdk/ the modding SDK, the project template and the community index's rules tools/ asset extraction, QVM disassembly, shader build, release and site tooling tests/ xUnit test projects ``` Nothing under `src/` may reference a concrete backend; the applications wire backends in. The architecture tests in `tests/OpenIGI.Core.Tests/Architecture` enforce this layering. Contributions are welcome. [`CONTRIBUTING.md`](https://github.com/OpenIGI/OpenIGI/blob/master/CONTRIBUTING.md) covers the determinism rules, the clean-room policy, which retail build is the reference, and how changes are tested. In short: open a pull request against `develop`, keep the Release build free of warnings, and keep the test suite passing. `tools/install-hooks.sh` installs the same checks as git hooks. OpenIGI is licensed under the [GNU General Public License v3.0](https://github.com/OpenIGI/OpenIGI/blob/master/LICENSE). Third-party components are listed in [`THIRD-PARTY-NOTICES.md`](https://github.com/OpenIGI/OpenIGI/blob/master/THIRD-PARTY-NOTICES.md). OpenIGI is a clean-room reimplementation for use with game data you already own. It is not affiliated with or endorsed by the owners of *Project I.G.I.* or *I.G.I. 2*. All trademarks belong to their respective owners. The repository contains no game assets, original source code or decompiler output, and contributions that include them are not accepted.