Immersive Portals Vulkan

By
hezhixin15

Unofficial Immersive Portals fork for Minecraft 1.21.1 (Fabric) that renders portals on VulkanMod with no OpenGL context.

Unofficial fork of Immersive Portals 6.0.6 for Minecraft 1.21.1 (Fabric) that runs on VulkanMod.

Immersive Portals lets you see through portals and travel between dimensions seamlessly. Upstream draws portal views with OpenGL. VulkanMod does not create an OpenGL context, so upstream cannot render portals at all. This fork adds a Vulkan-compatible rendering path so portals work with VulkanMod.

This project is not affiliated with qouteall, iPortalTeam or the VulkanMod project. Please report problems here, not upstream.

What is different from upstream

Terrain bridge: one VulkanMod terrain context per dimension, with chunk load and unload events routed to it.
Portal rendering without OpenGL: an off-screen framebuffer per portal, composited in a second buffer instead of the stencil buffer, with oblique near-plane clipping instead of glClipPlane.
Translucent layers inside a portal are re-sorted for that portal camera, and the viewport Y flip VulkanMod relies on is handled, which fixes water and translucent layers appearing upside down inside portals.
Indirect draw is kept: each portal pass appends its own draw parameters instead of overwriting a shared per-frame buffer.
Performance: a per-portal image cache (at most two live world renders per frame, the rest reuse the previous image), and conservative occlusion culling that skips a portal fully hidden behind a nearer one.
The OpenGL path is untouched. If you do not use VulkanMod, use the upstream mod.

Requirements

Minecraft 1.21.1 with Fabric Loader
Fabric API
VulkanMod 0.6.7 (the version this was tested on)
Java 21
Not compatible with Sodium, Iris or OptiFine

Installation

Remove any existing Immersive Portals jar from the mods folder. The mod id is still immersive_portals, so the two jars cannot coexist.
Put this jar, Fabric API and VulkanMod into the mods folder.

Known limitations

Only tested on 1.21.1 with VulkanMod 0.6.7.
Cached portal views lag by roughly 0.25 to 0.37 seconds while the camera moves, then become sharp once it stops.
GUI portal views and cross-portal views are not cached.
Every portal rendered live still costs a full world render, so frame rate drops as the number of live portals grows.
The water fix and the occlusion culling were verified structurally; bug reports with logs are welcome.