OptiCores is a client-side Minecraft performance mod for Fabric 1.21.1. The project focuses on reducing unnecessary rendering work and smoothing frame time without modifying Minecraft's gameplay simulation.
Minecraft client
-> immutable frame snapshot
-> bounded async visibility worker
-> generation-checked result
-> render-thread publication
-> Sodium/Iris render pipeline
- Distance, predictive, temporal, frustum, and conservative occlusion stages.
- Occlusion tests are capped and cached.
- Worker threads never access live world, entity, or chunk objects.
- Adaptive CPU work budget based on hardware tier and current pressure.
- Chunk priority includes distance, camera direction, and movement direction.
- VBO upload and chunk meshing timings are measured rather than guessed.
- Required uploads are never dropped by OptiCores.
- Frame-time feedback with hysteresis prevents rapid quality oscillation.
- Bottleneck classification distinguishes CPU/chunk pressure from likely GPU-bound frames without forcing GPU synchronization.
- Shadow-distance and LOD pressure can be reduced when frame time is persistently high.
Optional integrations are isolated from the core where practical. Simulation-changing entity, AI, lighting, and particle tick optimizations are intentionally not enabled.
Use /opticore benchmark in a test world. Compare Vanilla, Sodium, and Sodium + OptiCores using the same camera path and scene. Record average FPS, 1% low FPS, 0.1% low FPS, frame time, tick time, meshing time, and upload time.
- Minecraft: 1.21.1
- Fabric Loader: 0.16.5+
- Java: 21+
Build locally with ./gradlew build. The repository is designed for runtime verification against the exact Fabric/Yarn/Sodium/Iris versions used for release.