Voxy Iris Reverse-Z Fix
A small client-side compatibility patch for Voxy when used with Iris 1.11.4+ and a shaderpack (e.g. Photon).
Fixes sky textures clipping through distant LOD terrain and broken lighting when using Iris shaders with Voxy
What it fixes
Iris 1.11.4 replaced its old "switch the world to forward-z while shaders are active" with a depth transformer: the world now stays in the native reverse-z layout and pack shaders get translated (depth reads/writes inverted, gbufferProjection undo-rev-z'd, ...).
Voxy versions built before that change still force forward-z whenever a shader pack is active, so:
- Voxy's own depth buffers/projection disagree with the framebuffer Iris renders into.
- vxDepthTexOpaque and vxDepthTexTrans contain forward-z values while Iris inverts them before the pack sees them, so pack code such as Photon's is_lod_terrain() classifies sky pixels as LOD terrain. The result is broken/duplicated sky textures and broken LOD shading.
- Voxy's injected shader patches (voxy_opaque.glsl and voxy_translucent.glsl) read depthtex1 / vxDepthTex* / gl_FragCoord with nobody transforming them.
This mod makes Voxy advertise the native reverse-z state, hands the pack undo-rev-z'd vxProj/vxViewProj matrices and runs the injected patch glsl through Iris' own TransformPatcher.patchDepth().
Requirements
Voxy Iris Reverse-Z Fix Team
