1.21.11 Renderer

A Fabric client mod for Minecraft 1.20.4 that backports rendering improvements from 1.21.11.

Requirements

• Minecraft 1.20.4
• Fabric Loader 0.19.3 or later
• Fabric API 0.97.3+1.20.4

What it does

GPU backend (blaze3d)

Ports the 1.21.11 blaze3d rendering stack into 1.20.4. This includes the new GpuDevice/RenderPass/CommandEncoder abstraction, pipeline-based shader system, and the RenderPipeline / CompiledRenderPipeline classes. The backend is initialised after the OpenGL context is ready and replaces the relevant parts of 1.20.4's rendering path via Mixin.

Frame pacing

Caps the frame rate at the monitor's refresh rate when the in-game FPS limit is set to "Unlimited". Vanilla 1.20.4 renders without any throttle at that setting, causing the GPU to run at 100% producing frames the display can never show. On a 144 Hz monitor this reduces GPU load significantly with no visible difference.

Fog rendering

Replaces 1.20.4's BackgroundRenderer.render() call in WorldRenderer with the 1.21.11 fog pipeline, which includes improved fog modifiers for different dimension and environment types.

Chunk build scheduling

Replaces 1.20.4's dual-queue chunk rebuild system with a proximity-aware scheduler that prioritises chunks closest to the camera, matching 1.21.11 behaviour.

Leash-aware frustum culling

Fixes a visual glitch where a leashed mob at the edge of the screen is culled while its holder is still visible, causing the leash rope to render without one endpoint. The fix checks the holder's bounding box as well as the union of both boxes before culling, matching 1.21.11's EntityRenderer.shouldRender() logic.

Blocking pose item transform

Fixes the gap between the player's arm and a held item when blocking with a non-shield item (sword, axe, etc.). Vanilla 1.20.4 only applies the equip offset in the BLOCK use action case, leaving the item in its default position while the arm rotates. The fix applies the same rotation correction that 1.21.11 introduced to align the item flush with the raised arm.