About This Fork
This is a compatibility fork of Immersive Portals for NeoForge by qouteall/iPortalTeam, fixing three issues that break the mod on current Sodium, Iris, and Distant Horizons versions on NeoForge 1.21.1:
- Sodium 0.8.x compatibility — `OcclusionCuller.Visitor` was promoted to a top-level interface, and `Viewport.isBoxVisible` was split into two methods with a different signature. Without this fix, the game crashes on world join with Sodium 0.8.x installed.
- Portal occlusion with shaders active — with Iris and a shaderpack enabled, portals would render *through* occluding geometry (or silently fall back to a degraded compatibility mode). Root cause was a depth-buffer format mismatch between this mod's internal framebuffers and Iris's actual render target format.
- Distant Horizons stutter — severe frame-time spikes (900ms+) when a portal was visible with Distant Horizons installed, caused by DH doing synchronous LOD terrain generation for the portal's alternate-world view every frame. This fork skips that work specifically during portal rendering, with no effect on normal LOD rendering.
Full technical writeup and diffs: Upstream PR #71. Submitted upstream first — this CurseForge listing exists because that repo has had no commits in over a year and several correct, complete PRs sitting unreviewed, so a build people can download seemed worth having in the meantime (and me and my server are using it ourselves).
Licensed Apache 2.0, same as the original. All credit for the mod itself goes to qouteall and the iPortalTeam contributors — this fork only touches the Sodium/Iris/Distant Horizons compatibility layer.
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Original Mod Description
(from the original project)
Immersive Portals is a Minecraft mod that provides see-through portals and seamless teleportation. It also can create "Non-Euclidean" space effects.
This mod changes a lot of underlying Minecraft mechanics. It allows the client to load multiple dimensions at the same time and synchronize remote world information (blocks/entities) to the client. It can render portal-in-portals. The portal can transform player scale and gravity direction.

