Iris for Forge

Iris 1.7.2 - Forge port for Minecraft 1.20.1

An unofficial port of Iris 1.7.2 to MinecraftForge 1.20.1. Client-side only. Built and tested against Forge 47.4.10, with a shader pack loaded in a live world.

Requires a Sodium for Forge

Iris needs Sodium. Use the LGPL Forge port of Sodium 0.5.11 published alongside this file. It will not work with Embeddium or with any other Sodium fork: Iris mixes directly into Sodium's own classes, and those mixins are written against 0.5.11.

Why 1.7.2 and not something newer

1.7.2 is the last Iris built against a Sodium that is still LGPL (0.5.10). From Iris 1.7.3 onwards, Sodium moves to the PolyForm Shield licence, which does not allow this port to exist. The gap between 0.5.10 and the 0.5.11 used here is a single bug fix.

What the port had to change

Forge threads its own model data through the whole block rendering path, which shifts method signatures and local variables everywhere Iris hooks in. Its Mixin is also older than Fabric's and refuses several injection points inside constructors. Roughly twenty such differences were resolved; the full list is in the source archive's README.

MixinExtras is bundled and relocated, because Forge 1.20.1 does not provide it (NeoForge does).

Licence and source code

Iris is LGPL v3, and this port keeps that licence. The complete modified source is available on request through this project's comments, and a public repository link will be added here as soon as it is up.

Compatibility

Minecraft 1.20.1, MinecraftForge 47.x, Java 17. No network access: this port removes Iris's update checker entirely, so the mod downloads nothing and contacts no server.

Known cosmetic warnings

Shader packs written for newer Minecraft versions may log a few Unknown variable lines for uniforms Iris 1.7.2 does not know (BIOME_PALE_GARDEN, endFlashIntensity, ...). These are harmless and behave exactly the same on Fabric.

All credit for the rendering work goes to the Iris team. This port only adapts it to another mod loader.