Pulsar Lighting Engine

This is a mod exclusively for Cleanroom. It requires Java 25 and Cleanroom 0.6.10 or later.

Pulsar is an asynchronous lighting engine built for Cleanroom. It reimplements Starlight-style algorithms for Cleanroom and runs lighting calculations on separate threads.

Requirements

• Cleanroom 0.6.10-alpha or newer

Features

• Runs server-side light propagation on separate threads.
• Batches large groups of block changes instead of processing lighting separately for every edit.
• Caches light data in each chunk's NBT to avoid unnecessary full relights.
• Keeps Vanilla's block-light and sky-light data synchronized, so removing Pulsar does not corrupt your world.
• Includes various lighting bug fixes and quality-of-life improvements.
• Adds natural lighting to Thaumcraft crystals.
• Fully compatible with rendering mods such as Celeritas, Actinium, and Nothirium.

Fixed Bugs

• MC-92
• MC-1531 — smooth lighting across painting tile boundaries.
• MC-3329
• MC-80966
• MC-104532
• MC-116690
• MC-117067
• MC-117094
• MC-249343

Supported Mods

• Celeritas: fixes lighting bugs involving stairs and slabs.
• Fluidlogged API
• Depths Update: supports dimensions extending below Y=0 or above Y=255.
• JSON Paintings: fixes smooth-lighting bugs affecting paintings.

Incompatible

• Alfheim
• Phosphor for Forge
• Hesperus
• Other Starlight backports or mods that replace or rewrite the lighting engine
• The standard edition of The Aether II, which bundles Phosphor. Use The Aether II: Phosphor Not Included instead.

Unsupported or Untested

• CubicChunks
• OptiFine

Performance

Pulsar 0.5.0 Benchmarks

Block Placement and Removal

Sky Opening and Closing

Server Load During Continuous Editing

These values measure main-thread MSPT. Async worker CPU time is not included.

Flat Terrain Generation

Travel in a Flat World

Credits

• Starlight by Spottedleaf: the algorithms on which Pulsar is based.
• SuperNova by GTNewHorizons: an RGB lighting engine inspired by Starlight.
• Alfheim by Red Studio: a reference for directional neighbor brightness, liquid and emissive-block rendering, and light-only chunk packet handling.
• CleanroomModTemplate, TokenEnvoy, and CleanroomVersioning by CleanroomMC.

AI Disclosure

Pulsar uses LLM assistance in the following areas:

• Some code: primarily understanding and implementing algorithms.
• Translation and writing: translating into other languages and generating documentation.

License

Pulsar is licensed under the LGPL-3.0.