Play Quake 4 on modern systems with an open-source engine and game-code replacement built around the original retail assets.

Get Started | Features | Player Docs | Build from Source | Technical Reference

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What is openQ4?

openQ4 is an open-source replacement for the Quake 4 engine and game binaries, built to keep the original game playable on modern PCs while improving presentation, controls, packaging, and day-to-day usability.

It is designed for players who want the original Quake 4 experience with a cleaner path to running it on today's hardware.

Note

openQ4 does not include Quake 4 assets. You still need a legitimate Quake 4 copy from Steam or GOG.

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Why players use openQ4

• Modern display support for widescreen, ultrawide, multi-monitor, borderless, and fullscreen setups.
• Optional visual upgrades such as bloom, HDR, anti-aliasing, baked light grids, soft particles, and enhanced shadow options.
• Improved input and quality-of-life features including controller support, better console UX, and modern settings behavior.
• Single-player and multiplayer in one install with active compatibility work aimed at the stock game.
• Cross-platform support with Windows and Linux release packages, Steam Deck support on Linux, and a signed/notarized macOS DMG lane for credentialed release runs.
• Open development with releases, issue tracking, and community feedback all happening in public.

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Renderer showcase

_{Bloom and HDR on mp/q4dm2 from the same loadscreen camera: normal rendering on the left, enhanced post-processing on the right.}

_{Baked light-grid indirect diffuse on mp/q4dm2, shown off and on from the same loadscreen camera.}

_{CRT post-processing on mp/q4dm8, shown off and on with a clean no-HUD camera.}

_{A second CRT comparison on mp/q4dm6 shows the same post-process across a brighter indoor arena.}

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Quick start

1. Install Quake 4 from Steam or GOG.
2. Download the latest openQ4 build from the Releases page.
3. Launch openQ4-client_<arch> (or openQ4-steamdeck on Steam Deck).
4. If openQ4 does not find your Quake 4 install automatically, follow the path setup notes in the Getting Started guide.

Need the step-by-step version? Start with docs/user/getting-started.md.

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Player guides

Start here

• Getting Started - installation, first launch, and common setup questions
• Client Settings Guide - where to find the most useful in-game settings
• Server Setup Guide - basic dedicated server setup and common server variables

Play and tune

• Display Settings - fullscreen, windowed mode, resolution scale, and multi-monitor behavior
• Input Settings - keyboard, mouse, controller, and binding help
• Gameplay Settings - gameplay and audio toggles for everyday play
• Steam Deck - launcher, controls, and Linux handheld notes
• Multiplayer Networking - multiplayer tuning and lag-comp behavior
• Shadow Mapping - optional shadow-map settings and troubleshooting
• Light Grids - advanced lighting guide for players and testers

Build and technical docs

• BUILDING.md - compile openQ4 from source
• TECHNICAL.md - advanced configuration, file layout, compatibility notes, and mod details

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Compatibility at a glance

• openQ4 targets the official Quake 4 retail assets.
• It ships its own engine and game modules.
• It is not a drop-in runtime for the original proprietary Quake 4 DLL mods.
• The project is still in beta development, so compatibility work is ongoing.

If you run into problems, please use the issue tracker and include crash logs or setup details when possible.

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Contributing

Bug reports, compatibility reports, testing feedback, and code contributions are all welcome. If you want to help build the project itself, start with BUILDING.md.

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Credits

• themuffinator - openQ4 development and maintenance
• DarkMatter Productions - project stewardship and website
• Justin Marshall - Quake4Doom and early BSE reverse engineering reference work
• Robert Beckebans - renderer modernization reference work, including RBDOOM-3-BFG inspiration
• id Software and Raven Software - Quake 4 and the underlying technology
• akacross (Discord user) - Thorough playtesting on Linux and Windows, a huge help moving the project forward!

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License and disclaimer

openQ4 engine code is licensed under the GNU General Public License v3.0. See LICENSE for details.

The game-library code in openQ4-game is derived from the Quake 4 SDK and remains subject to id Software's SDK EULA. Quake 4 assets remain the property of id Software and ZeniMax Media.

openQ4 is an independent project and is not affiliated with, endorsed by, or sponsored by id Software, Raven Software, Bethesda, or ZeniMax Media.

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