Chlorine is a Fabric performance and power-management mod for Minecraft 26.3. It targets CPU-side simulation work, bursty entity effects, and laptop power usage while leaving chunk rendering and renderer internals to specialized mods.

Current release: 1.0.2

The last version made for Minecraft 26.2 was 1.0.0.

• Adaptive simulation distance: monitors a rolling FPS average and lowers simulation distance when performance falls below the configured threshold. It raises the value again after a longer recovery cooldown.
• Entity-distance scaling: can reduce the entity-distance multiplier after simulation distance reaches its configured floor.
• Particle fallback: can reduce the particle setting as a last resort.
• Simulation-distance cap: optionally prevents other tuning systems from raising simulation distance above a fixed ceiling.
• Fast-travel chunk governor: temporarily lowers simulation distance while moving quickly, such as with an Elytra or Riptide trident, then restores it after a cooldown.

Chlorine intentionally changes simulation distance, not render distance. Render-distance changes can rebuild the entire chunk render graph and cause a large hitch; simulation distance instead targets server ticking, entity updates, random ticks, and block updates.

• Distant classic-mob AI throttle: staggers goal-selector AI for mobs such as zombies and skeletons when no player is nearby. Physics and nearby mobs are not throttled.
• Distant Brain-mob throttle: applies the same idea directly to Brain.tick() for villagers, piglins, hoglins, allays, frogs, and other Brain-driven mobs.
• Item merging: periodically combines compatible nearby item entities around online players.
• XP orb merging: combines nearby experience orbs. The implementation verifies the internal value update before discarding an orb and disables itself for the session if that operation cannot be verified.
• Server tick diagnostics: optionally logs a warning when average server tick time exceeds the configured threshold. This is observability only; it does not alter server behavior.

• Unfocused-window power saver: caps FPS while the game window is unfocused or minimized and can hide clouds during that period.
• Sound budget: limits how many new sounds may start in one client tick, smoothing bursts from farms, combat, or other events.
• Sound pre-cull: drops very quiet distance-attenuated sounds before they reach the audio engine.
• Particle budget: limits particle creation per client tick to smooth fireworks, explosions, potion clouds, and similar bursts.
• Beacon and portal throttles: skips distant beacon beams and Nether portal ambient particles when enabled.
• Low-end auto-tune: once per launch, detects constrained memory or CPU availability and applies lighter vanilla visual defaults.

All features are independently configurable and can be disabled without removing the mod.

• Minecraft 26.3
• Fabric Loader 0.19.5 or newer
• Fabric API
• Java 25 or newer
• Cloth Config API (required)

Mod Menu is optional. When installed, it adds Chlorine's Config button to the mod list. Chlorine is designed to coexist with Sodium, Lithium, FerriteCore, EntityCulling, ImmediatelyFast, and Iris; none of those mods is required.

1. Install Fabric Loader for Minecraft 26.3.
2. Install Fabric API and Cloth Config API.
3. Place chlorine-1.0.2.jar in the instance's mods directory.
4. Optionally install Mod Menu for the in-game configuration screen.

The configuration file is created at:

config/chlorine.json

Changes made through the Cloth Config screen are written to the same file.

The in-game screen groups settings into:

• Simulation Distance Cap
• Adaptive Scaler
• Power Saver
• Mob AI Throttle
• Item Merging
• XP Orb Merging
• Sound Budget
• Particle Budget
• Low-End Auto-Tune
• Beacon & Portal Throttle
• Chunk Gen Governor
• Sound Pre-Cull
• Tick Diagnostics

Important interactions:

• The adaptive scaler, chunk governor, and simulation-distance cap all operate on the client simulation-distance option.
• Chlorine allows the client simulation-distance option to go down to 1 chunk. The adaptive scaler, chunk governor, and cap can all use that floor.
• Changing simulation distance manually while playing updates the adaptive scaler's restore target.
• Lowering AI throttle intervals improves responsiveness but reduces the possible CPU savings. Start with the defaults and adjust gradually.

This repository includes the Gradle wrapper. Use:

./gradlew build

On Windows:

.\gradlew.bat build

The build requires Java 25 and internet access for Minecraft, Fabric, and library dependencies. Output jars are written to:

build/libs/

The GitHub Actions workflow in .github/workflows/build.yml builds with Temurin Java 25 and Gradle 9.5.1, then uploads the jars as workflow artifacts.

src/main/java/com/chlorine/
  Chlorine.java                 Common Fabric entrypoint
  ChlorineConfig.java           JSON configuration and defaults
  ItemMerger.java               Nearby item-entity merging
  XpOrbMerger.java              Defensive XP-orb merging
  ServerTickDiagnostics.java    Server tick-health logging
  mixin/                        Common AI mixins

src/client/java/com/chlorine/client/
  ChlorineClient.java            Client entrypoint and tick orchestration
  PerformanceScaler.java         FPS-driven simulation tuning
  PowerSaver.java                Unfocused-window power saving
  ChunkGenGovernor.java          Fast-travel tuning
  SimDistanceCap.java            Simulation-distance ceiling
  LowEndAutoTune.java            One-time low-end defaults
  ChlorineConfigScreenBuilder.java
                                  Cloth Config screen

src/client/java/com/chlorine/mixin/client/
                                  Client sound, particle, beacon, and portal hooks

The mod uses Fabric lifecycle events for periodic work and narrowly scoped Mixin injections for Minecraft internals. It does not replace the renderer, rewrite chunk storage, or add blocks, items, entities, or world-generation content.

• Performance results depend on the world, entity count, hardware, and other installed mods. The defaults are conservative but are not universal benchmarks.
• Throttling distant AI intentionally trades some background simulation frequency for lower CPU usage.
• LightmapThrottleMixin is parked in disabled-mixins/ and is not part of the build because the targeted lighting class changed in the 26.x rewrite.
• XP orb merging fails safe: if the orb value field cannot be read or written, the feature disables itself for that session instead of risking XP loss.

This project is FULLY AI generated. Except the README, that I did. But EVERY OTHER PART of this mod was made with AI, using Claude, Chatgpt Codex, and Github Copilot. Uh, this may come a suprise to some people (if there are any downloading this mod) but it still works. I personally test every single version and have the ideas to implement them. Now, this isnt a promise, but I want to learn how to code myself, and 2.0.0 (unless stated so) will be the version which I code it. Hopefully 😭 k byee.

All Rights Reserved. See LICENSE.