Render negative-Y sections on 1.18+ worlds - #485
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Sections below y=0 were never meshed: worldrenderer's dirty-section loops hardcoded the pre-1.18 0..256 range, and the worker's section-presence guard indexed chunk.sections by y/16 even though ChunkColumn indexes sections from minY (-64 since 1.18), so negative sections resolved to undefined and were skipped. Any camera below y=0 saw only the clear color. Derive minY/worldHeight from the version's chunk implementation, index worker sections by (y - minY) / 16, and gate models.js face culling on world.minY instead of 0.
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A camera below y=0 renders nothing but the clear color: a bot standing on the surface of any 1.18+ world (surface ~y=-60 in the overworld's lower range, or anywhere in a deepslate cave) shows a uniform sky-blue frame with the surrounding chunks fully loaded. Three spots hardcode the pre-1.18 world range [0, 256): - worldrenderer.js dirty-section loops in addColumn/removeColumn iterate y=0..240, so sections below y=0 are never queued for meshing - worker.js indexes chunk.sections[floor(y/16)], but 1.18+ ChunkColumn indexes from minY (-64): sections[(y - minY) >> 4]; y<0 resolves to sections[-1] = undefined and the section is skipped - models.js culls faces against a hardcoded y<0 instead of the world's minY Derive minY/worldHeight from the version's chunk implementation (defaults 0/256, so pre-1.18 is unchanged), iterate the real range, index worker sections by (y - minY)/16, and gate models.js culling on world.minY. Revives PrismarineJS#485 (closed); no longer stacked on the 26.1 PR.
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Stacked on #484 — merge that first, after which this PR's diff collapses to just the last commit.
Problem
Any camera below y=0 renders nothing but the clear color — e.g. a mineflayer bot standing in a deepslate cave shows a uniform sky-blue frame, even with the surrounding chunks fully loaded.
Cause
worldrenderer.jshardcodes the pre-1.18 world range: the dirty-section loops inaddColumn/removeColumniteratey = 0..240, so sections below y=0 are never queued for meshing.worker.js's section-presence guard indexeschunk.sections[Math.floor(y / 16)], butChunkColumn(1.18+) indexes sections fromminY(-64):sections[(pos.y - this.minY) >> 4]. For y < 16 sections this resolves to the wrong index, and for y < 0 tosections[-1]= undefined, so those sections are skipped. (Above ground it is accidentally harmless — sections are dense and geometry is read via absolute coordinates — but the guard checks the wrong slot.)models.jsculls faces against a hardcodedy < 0instead of the world'sminY.Fix
minY/worldHeightfrom the version's chunk implementation insetVersion(defaults0/256, so pre-1.18 behavior is unchanged) and iterate the real range inaddColumn/removeColumn.(y - (chunk.minY ?? 0)) / 16.minYon the worker'sWorldwrapper and gatemodels.jsface culling onworld.minY ?? 0.Verification
setVersion('26.1')→{ minY: -64, worldHeight: 384 };1.16.5/1.12.2→{ 0, 256 }(new Chunk()constructs fine on old versions)World.addColumn(fromJson): the y=-16 section resolves and the block reads back throughworld.getBlockaddColumnon 26.1 now queues 20 negative-Y section jobs per column (previously 0)