Pulsar

A high-performance lighting engine mod for Minecraft 1.12.2, built on Starlight's BFS propagation algorithm.

Warning

This mod is still in the early stages of development. As no precise benchmarks or tests have been carried out, we cannot guarantee its effectiveness.

Overview

Pulsar replaces Minecraft’s default lighting engine with a modern BFS-based implementation derived from Starlight. It is intended for use with CleanroomLoader.

Bringing the power of Starlight to 1.12.2.

What It Does

• Replaces vanilla's slow, iterative light propagation with Starlight-equivalent BFS
• Uses SWMR (Single Writer Multi Reader) nibble arrays for thread-safe concurrent lighting
• Runs light computation on dedicated worker threads with time-budgeted drain loops
• Writes results back to vanilla blockLight/skyLight nibbles — fully transparent to other mods

What It Doesn't Do

• No RGB / colored lighting (scalar only — same visual output as vanilla)
• No custom rendering pipeline — works through vanilla Chunk.getLightFor(), so renderers like Celeritas read correct values automatically

Requirements

• CleanroomLoader

Credits

• Claude — During development, Claude’s ideas came to our rescue on numerous occasions.

• Starlight by Spottedleaf — the architecture and core algorithms (BFS propagation, SWMR nibble arrays, deferred lighting) are derived from Starlight's design.

• SuperNova by GTNH — the RGB colored lighting engine for 1.7.10. Pulsar is a scalar-only port of SuperNova's Starlight-derived BFS engine, with all RGB / color features removed. The majority of Pulsar's light engine, mixin targets and chunk-send strategy are 1:1 conversions of SuperNova's sources.

• Hodgepodge by GTNH — Pulsar's MixinChunk.pulsar$alwaysPopulated (the chunk-send gate bypass) is the 1.12.2 equivalent of Hodgepodge's MixinChunk_SendWithoutPopulation, and MixinWorldEntitySpawner mirrors Hodgepodge's MixinSpawnerAnimals_optimizeSpawning "skip mob spawning in chunks with pending light" behaviour. Hodgepodge's sources were consulted directly while porting both.

• Alfheim by Desoroxxx — Pulsar's BFS queue dedup layer (PulsarEngine.DEDUP_MASK + LongOpenHashSet-gated appendToIncreaseQueue / appendToDecreaseQueue) is modelled on Alfheim's DeduplicatedLongQueue, the Phosphor-derived trick that collapses duplicate (coord, level) enqueues before they reach the drain loop.

• GTNHLib by the GTNH team — SuperNova's 1.7.10 build depends on GTNHLib for its annotation-driven config, coordinate utilities, blockpos backport and gtnhmixins declarative mixin loader. Pulsar does not link against GTNHLib (1.12.2 ships modern equivalents via Forge / mixinbooter), but the design of Pulsar's config and coremod entry point is informed by how SuperNova uses GTNHLib.

• CleanroomModTemplate by the CleanroomMC

License

LGPL-3.0