Extends ChunkAdapter with readSections() (reads non-empty 16x16x16
sections via the chunk's ExtendedBlockStorage array, skipping fully-air
ones for free) and DeltaSink with onChunkDirty(), additive to Phase 1's
column-based readChunk()/onDelta — 2D column tracking is unchanged.
BackendConnection grows sendSections(), base64-encoding each section's
4096-entry char[] (char, not short, since short would overflow for any
blockId >= 2048 — see SectionData's javadoc) into the wire protocol's new
"sections" message, mirrored in MCMapper-Backend's matching commit.
MCMapperMod now tracks dirty chunks (not just dirty columns) and, on the
same flush tick as column deltas, re-reads and resends full section data
for any chunk touched since the last flush — same "current state, not a
diff" approach as columns, at chunk instead of column granularity.
Verified against a live MCMapper-Backend instance: a known half-solid
section sent through this exact code path round-trips to a mesh with
exactly 24 vertices / 36 indices at the backend's mesh-serving endpoint,
matching the worker's greedy-mesher unit tests for a uniform section.
octoturge
2b7e0e090d