Thunderhead 2.0 — Lightning & Thunder

Minecraft 1.21.1, Java 21, Fabric or NeoForge.

Thunderhead replaces lightning with procedural channels, shared return-stroke timing, distributed thunder and optional server-driven storm activity. It uses bounded physical approximations designed for Minecraft, rather than claiming a complete plasma or atmospheric simulation.

• One channel per flash. A weak leader and a fast return front use the same topology as subsequent impulses. Brightness is integrated over frame intervals instead of relying on a single sample.
• Four discharge categories: negative and positive cloud-to-ground, intracloud and intercloud. Cloud events do not create ground-impact particles or damage.
• Stable realistic geometry. Lower detail retains vertices from a canonical backbone; endpoints remain fixed and forks attach to retained vertices.
• Thunder along the channel. Up to eight spatial sources follow the flash's pulse plan. Arrival uses distance / 343 m/s and the listener's current position. Optional local shelter attenuation selects a muffled profile behind obstacles.
• Surface illumination. A private depth snapshot reconstructs visible surfaces and approximate normals. Up to four channel samples illuminate them with bounded screen-space occlusion checks.
• Server storm cells. Small charge reservoirs drift, build activity and decay during Minecraft thunderstorms. An optional versioned protocol shares event IDs, seeds, kinds, endpoints and start times, with bounded deduplication and late-arrival handling.
• Ground conduction. Additional near-miss damage can depend on connected surface materials and whether the target contacts the ground. A short side-flash approximation is separately opt-in. Vanilla's own damage region is excluded by bounding-box intersection.
• Accessibility and budgets. Reduced flashing preserves saved preferences, removes the pulse train, suppresses vanilla sky flashes and limits new visual flashes across the storm. Sound, particles, geometry and network queues have explicit caps.

Install exactly one jar for your loader:

• Fabric Loader 0.16.14+ and Fabric API for Minecraft 1.21.1.
• NeoForge 21.1.x; development verification uses 21.1.248.

Client only: vanilla server lightning receives local visuals and audio. The mod does not change server gameplay or invent a synchronized server storm.

Client and server: optional storm synchronization and server gameplay settings are available. Extra storm-generated ground strikes are off by default. Cloud activity does not modify blocks. Operators can enable additional real strikes explicitly.

Ball lightning remains an experimental gameplay feature and is off for new server configurations. Existing explicit settings are preserved.

The normal channel renderer uses its own programs and framebuffer, then composites into the finished scene. This preserves the mod's pulse appearance without requiring edits to a shader pack. True vanilla bolts retain their vanilla entity renderer if the mod's custom programs are unavailable under a pack.

Surface lighting is an approximation from the available depth. It cannot recover off-screen occluders, a pack's cloud density, or its reflection and exposure buffers. Full volumetric cloud lighting and pack-native reflections are not promised. Transparent water, alternate depth pipelines and other GPUs need combination-specific testing.

An experimental native-material route was tested and removed: Complementary replaced supplied channel brightness/color and introduced depth artifacts. It is not part of the supported 2.0 path.

See the compatibility matrix for exact tested combinations and limitations. No finite test matrix proves compatibility with every existing or future shader pack.

Use /tempestfx settings, ModMenu on Fabric, or NeoForge's config button.

• Realistic is selected for new client configs: restrained impacts, a coherent flash and channel-based thunder.
• Cinematic preserves enhanced impact rings, stronger decorative effects and audio-driven distant walls. Existing configs keep this presentation unless changed.
• Explicit /tempestfx roll previews work in both profiles and appear ahead of the player. Distant bolts must be enabled; reduced flashing suppresses these visual cues.
• Settings mark unavailable effects and explain their profile or dependency requirements in tooltips. See the mechanism audit.
• Quality presets adjust geometry, particle/effect budgets and surface-lighting cost. They are independent of presentation and accessibility.
• Disable shelter attenuation if an acoustic mod already handles obstruction.

Files are config/tempestfx.json and config/tempestfx-server.json. /tempestfx reload reloads the client config and the integrated server's config. Dedicated-server config is read on server start.

Important server settings:

The extra-strike target search examines at most 289 already-loaded columns near its candidate, favoring exposed height and lightning rods. This local search is an approximation; ordinary vanilla targeting and its lightning-rod behavior are unchanged. Damage and ignition remain server decisions. Cosmetic vanilla bolts do not receive additional gameplay damage.

/tempestfx settings
/tempestfx reload
/tempestfx strike 40 --seed 12345
/tempestfx type negative_ground 12345
/tempestfx type positive_ground 12345
/tempestfx type intracloud 12345
/tempestfx type intercloud 12345
/tempestfx stress 20
/tempestfx summon
/tempestfx ball
/thunderstorm status
/thunderstorm strike 152 71 197

strike, type and stress under /tempestfx are visual tests. summon, ball and /thunderstorm strike create real entities; server commands require operator permission. Server strike targets must already be loaded.

Build instructions, architecture, API, physical approximations, implementation/verification journal.

buildAll tests the shared implementation and builds both loader jars. Test captures use disposable saves; source media in the neighboring project is not modified. No external shader assets are bundled.

Made by GestSe. Code and original bundled assets: MIT. See asset provenance.