OpalLight —— Colored Light API

Overview

OpalLight provides a universal colored light API for Minecraft. Unlike common full-screen shader approaches, OpalLight uses per-block, voxel-level RGB light propagation——colors travel through blocks via BFS, attenuate with distance, mix across RGB channels, and take the strongest value within each channel. This means colored lighting renders correctly around corners and through complex geometry, rather than being a screen-space post-effect.

The key advantage: automatically compatible with the vast majority of Iris Shaders with zero user configuration. Also fully supports the VulkanMod renderer.

Core Features

Powerful Colored Light API

Data-driven + event-driven: Register colored light sources via JSON data files, or programmatically through the ModificationEvent.
StatePropertiesPredicate support: Different block states of the same block can emit different colors.
Zero-invasion integration: Any block from any mod can emit colored light——just register data or listen to the event.

True Color Propagation

Voxel-level BFS light propagation, with linear attenuation over Manhattan distance.
Per-channel multi-source merging: different channels mix naturally while equal channels use the strongest value, so removing a source remains exact.
Correct lighting regardless of terrain complexity——corners, crevices, and caves all light accurately.

Broad Compatibility

Iris Shaders: Automatically compatible with the vast majority of shader packs. No manual compatibility selection needed.
VulkanMod: Native support for the Vulkan renderer.
Custom shaders use Core Profile GLSL 150, standards-compliant to avoid rendering conflicts.

Example: Colored Lanterns

Seven colored lanterns are included as API usage demonstrations:

Lantern	Recipe
Red / Orange / Yellow / Green / Cyan / Blue / Purple Lantern	Vanilla lantern + matching dye (shapeless)

Each lantern is registered through OpalLight's API, showing how blocks are associated with RGB colors.

Showcase

Vanilla

Complementary

BSL

Photon

Mellow

VulkanMod

For Developers

// Listen to ModificationEvent to register colored light for any block
@SubscribeEvent
public static void onLightModification(LightDataLoader.ModificationEvent event) {
    event.getDataByBlock().put(
        MyBlocks.GLOWING_CRYSTAL,
        List.of(new LightDataLoader.OpalData(new OpalColor(0.2f, 0.8f, 1.0f), Optional.empty()))
    );
}

Or drop a JSON file under assets/<modid>/opal_data/ for zero-code integration.

Compatibility

Project	Status
Iris Shaders	Auto-compatible with most shader packs
VulkanMod	Fully supported
NeoForge 1.21.1	Native platform
Other mods' light-emitting blocks	Compatible via API registration

Opal Light