irisshaders/iris

Iris is an open-source mod for Minecraft that adds support for shader packs, which are collections of visual effects that change how the game looks. Shader packs can produce effects like realistic water reflections, dynamic lighting, and atmospheric sky rendering. Iris was built to give players a free and open alternative to OptiFine, the dominant tool for loading these packs, which carries a restrictive license that limits tinkering and causes conflicts with other popular mods. One of the key reasons the project exists is compatibility with Sodium, a mod that significantly improves Minecraft's rendering performance. OptiFine and Sodium cannot run together, which forced players to choose between better visuals and better performance. Iris is designed to work alongside Sodium, so players can run their preferred shader packs without giving up the performance gains Sodium provides. The project has a set of stated goals it is still working toward: full use of the graphics card when paired with optimization mods, minimal bugs in the implementation, broad compatibility with both modded environments and existing OptiFine-era shader packs, and eventually new features for developers who create shader packs. The codebase is intended to stay well-organized so contributors can work with it comfortably. Iris has public releases for recent Minecraft versions and works with most popular shader packs. It is not considered finished software. Some OptiFine features are not yet fully replicated, and performance improvements continue to be made. Developers who make shader packs are also gaining new tools as the project matures. All code in the repository is released under the GNU LGPLv3 license, which allows anyone to read, share, and modify it within those terms. One dependency, glsl-transformer, carries an Affero GPL license that may affect redistribution. The project is supported by a community team handling support and moderation, along with open contributions from developers through pull requests.