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Fix latent client-side encode_binary bounds min+size/min+max bug (nonzero position)

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Found during review of the persistence-plumbing branch: _build_metadata_section
wrote raw bounds.size into the wire's 2nd float triple, but the wire format
(and _parse_metadata_section) treats that triple as max_pos, computing
size = max - min. AABB(Vector3.ZERO, size) masks this since size == max when
position is 0 -- exactly what every existing test used. Any chunk at a real,
nonzero world position would silently corrupt on its own client-local
encode/decode round-trip. Same bug class as the backend's min+size/min+max
mismatch fixed in chunk_codec.py (eb39e43), just on the client side this
time. Added a regression case to smoke_test_chunk_codec_interop.gd using a
real nonzero chunk position (96,-32,0) -- 33/33 passing. Full sibling smoke
suite re-verified clean afterward.
This commit is contained in:
daddy
2026-09-14 23:00:17 +00:00
parent fd88cef32f
commit 65995f30a6
2 changed files with 38 additions and 3 deletions
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scripts/chunk_data_decoder.gd
+13 -3
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@@ -492,12 +492,22 @@ static func _build_metadata_section(payload: ChunkPayload) -> PackedByteArray:
data.append_array(_write_int32(payload.coord.x))
data.append_array(_write_int32(payload.coord.y))
data.append_array(_write_int32(payload.coord.z))
# Wire format is min + max (world.md §3, and _parse_metadata_section
# below reads the 2nd triple as max_pos and computes size = max - min)
# -- writing raw `.size` here instead of `.position + .size` was a
# latent bug that only escaped every test because AABB(Vector3.ZERO, ...)
# happens to make size == max when position is exactly zero. Any chunk
# at a real, nonzero world position (i.e. every real chunk except the
# one at the origin) would round-trip through encode_binary/decode_binary
# with a corrupted size. Same bug class as the backend's min+size/
# min+max mismatch fixed in chunk_codec.py (commit eb39e43).
var bounds_max: Vector3 = payload.bounds.position + payload.bounds.size
data.append_array(_write_float32(payload.bounds.position.x))
data.append_array(_write_float32(payload.bounds.position.y))
data.append_array(_write_float32(payload.bounds.position.z))
data.append_array(_write_float32(payload.bounds.size.x))
data.append_array(_write_float32(payload.bounds.size.y))
data.append_array(_write_float32(payload.bounds.size.z))
data.append_array(_write_float32(bounds_max.x))
data.append_array(_write_float32(bounds_max.y))
data.append_array(_write_float32(bounds_max.z))
# Every other section builder wraps its body with `_wrap_section`
# (section_id + uint32 length prefix) -- this one didn't, so
# `encode_binary()` spliced the raw metadata bytes directly into the