Aeronautics Iris Fix

What it does

Create Aeronautics’ hot air balloon envelopes render incorrectly when an Iris shaderpack is active — a duplicate “ghost” copy of the envelope appears at a fixed spot on screen, and the balloon interior can wash out to opaque white.

This mod fixes both. Envelopes render correctly with shaders and real-time shadows on, and the levitite shimmer effect is preserved.

Why it happens

The levitite envelope effect draws extra “ghost layers” of geometry that a tessellation shader displaces into a shimmer. Veil only issues a GL_PATCHES draw when its own shader program is currently bound — under Iris, Iris binds its own gbuffer program instead, so that check fails and the draw silently falls back to plain quads with no tessellation stage. The ghost layers still get drawn, but the code meant to displace them never runs, so they appear as flat undisplaced duplicates.

Aeronautics already has a correct fallback for “tessellation is unusable” — it just has no way to know that the GPU supporting tessellation isn’t the same as tessellation surviving the Iris pipeline. This mod routes that case through Aeronautics’ own existing fallback path.

Requirements

• Minecraft 1.21.1 — NeoForge
• Create Aeronautics 1.3.0+
• Iris

Client-side only. Inert when no shaderpack is active — everything renders exactly as vanilla Aeronautics does with shaders off.