Hand-written test bodies in step_canvas.rs did not match rustfmt. Caught by
the pre-push gate, which is exactly its job — team-patterns.md's note that
fmt auto-fixes and clippy is a quick lead patch, rather than something agents
should pre-emptively duplicate.
No behaviour change.
Co-Authored-By: Claude <noreply@anthropic.com>
Global took its cell counts from `global_cell_counts()` — one gridunit per
region — and discarded the requested extent entirely. On GJ380c that produced
a 191x95 canvas built from a heightmap stored at 512x256: roughly seven times
the available cells thrown away before anything was drawn. The count also
shrank as REGION_M grew, so tuning the scale ladder silently degraded the
opener, which is why the top of the ladder got worse rather than better as
the ladder itself was refined.
Global now fits the largest 2:1 canvas inside the requested extent. It cannot
take its ASPECT from the viewport — the canvas is equirectangular whole-body,
360 degrees of longitude by 180 of latitude, and must stay 2:1 or the cells
stop being square and the map shears — so the existing letterbox absorbs the
remainder. A hostile extent is still clamped; sizing to the request is not
trusting the request.
Global also joins the deep display ratio, making the band uniform. At 5 px
per gridunit a 1920 px window asked for 384 cells across a body whose
heightmap holds 512x256 — discarding stored detail to save work already done.
At 2 px it asks for 960, which is heightmap-native: nothing thrown away,
nothing invented, and the same screen area filled either way.
A body with no radius is not a sphere (asteroid belt, oort cloud) and has no
equirectangular surface to fit. Those degrade to the region grid — a visibly
degenerate 1x1 canvas — rather than a plausible-looking lie at whatever size
the viewport happened to ask for.
project.yaml 0.4.3 -> 0.4.4 invalidates the persisted step-canvas disk cache.
District/Quarter/Block/Chunk kept identical 960x540 cell counts through the
extent inversion, so their cache keys are byte-identical while a District
canvas now covers 3.6 km of ground instead of 1,966 km — a warm cache would
silently serve pre-inversion canvases.
Global still rides the orbital derive, so it carries no courses yet; that is
the next step and is deliberately separate, being a cost question over the
whole body rather than a sizing one.
Pair session with Jeroen, 2026-07-26.
Co-Authored-By: Claude <noreply@anthropic.com>
A rung used to fix the gridunit SPACING, with the canvas extent falling out
of spacing x cell count. That is why the top of the ladder was unusable: at
REGION_M spacing a viewport-sized canvas spanned ~251,658 km — six times
around a rocky body — so the Region rung capped to the body and redrew the
Global picture pixel-for-pixel. "Global and region look the same" was not a
rendering bug; it was this relation, stated in metres.
Inverted: a rung fixes the EXTENT and the spacing falls out of the canvas
size. The shorter viewport axis spans exactly one cell of the rung's level,
so a widescreen window shows more ground on the long axis rather than less
on the short one. Every rung now shows the ground its name promises —
Region 262x466 km, District 4.1x7.3 km — and the canvas cell count is
viewport-driven and identical at every rung, so derive cost no longer varies
with depth and resize is free.
Consequences that fell out of the inversion rather than being chosen:
- Region leaves the orbital derive set. It was envelope-only because at
251,658 km nothing finer made sense; at 262 km it is a genuine provincial
map and takes the full courses-aware derive. Region having no rivers at
all was much of why the top of the ladder read flat. It also joins the
deep display ratio for the same reason.
- The S2 station-spacing floor is deleted, not retuned. It guarded an
O(1/spacing) blowup that the inversion makes structurally impossible (the
canvas cell count is now constant across rungs, so stations-per-course is
bounded however deep you scroll). Kept, it would do active harm in the
opposite direction: a 2,048 m pitch across a 3.6 km District canvas places
two stations and draws every river as a straight line. Station placement
gets its own generator pass.
- cap_extent_to_body is superseded and now a documented no-op. A canvas can
no longer over-request a body by construction. The residual question —
whether a rung's cell exceeds the whole body — is liveness, not capping,
and is_rung_live_on_body() answers it by omitting the rung. Empirically it
never fires on inhabited content: all six rungs are live on all 271
populated bodies with a radius.
- snap_to_gridunit no longer truncates its multiplier to int. Post-inversion
the deep rungs run sub-metre (Chunk ~0.12 m at a 1080 px short axis), where
int(spacing) floors to zero and would collapse every request centre onto
the origin.
Both sides derive spacing from the same three inputs (rung, echoed cell
extent, body radius) rather than one telling the other, so there is nothing
to keep in sync beyond the constant table itself. Body radius already
reaches the viewer via enter(); no wire change.
Pair session with Jeroen, 2026-07-26. D-243/D-255 amendments to be backfiled.
Co-Authored-By: Claude <noreply@anthropic.com>
Hoshe's review finding: the build_step_canvas row-space convention block
still described region_centre_latitude_deg as pole-anchored/bugged and
said 'T-1186 stays open' — both false after this PR's own first commit.
Rewritten to reflect the fixed state; the deliberate signed-convention
rationale and the layer_proxy deferral (still true, still T-1181's scope)
are preserved.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Lake edges rendered as hard step-edges while ocean coasts got multi-tone
transition bands: every coastal-transition morphology gate keys on
ocean_fraction_q, definitionally 0 inside a lake basin (hypothesis (b)
of the ticket; (a) disproven first — a shoreline-crossing sweep at
2048/512/128m plus a 10m fine sweep all land on the same continuous
crossing, so positional refinement was never broken). New
DistrictProfile.lake_margin_q (0-100 settled-hydrology depth band, from
the same bilinear filled/elevation pair the lake test already samples;
ceiling calibrated just above the observed p90 depth on GJ338Bd's 5,043
flooded cells), threaded through both derive paths onto
EncodedStepCanvas (serde-default for shape tolerance) and down the
client: protocol decode, terrain-layer plane, colorize shades Lake cells
by depth band instead of elev_q (bedrock-under-water, the wrong signal).
project.yaml 0.4.0 -> 0.4.1: the new wire field must invalidate the
client disk cache via its version tag (T-1183's D-192 mechanism).
Acceptance gates green with the new field (lossless round-trip,
cache-hit==cache-miss, every rung).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Hoshe finding 1: StepCanvasRequest.extent is no longer wire-trusted —
clamp_step_canvas_extent enforces the D-255(b) canvas budget at the
request boundary (per-axis cap 3840 defeating u32::MAX before any
multiplication, then an aspect-preserving total-cell ceiling at the
measured 3840x2160 = 8,294,400-cell workshop budget), mirroring the
legacy carrier's clamp_window_n_v2 discipline; the Global rung ignores
the wire extent entirely. StepCanvasResponse gains the extent echo
field so a client can detect the clamp (the DistrictWindowLayer.n
precedent — a pre-existing gap closed in passing, recorded on the
ticket for T-1182). Seven new tests including an end-to-end u32::MAX
request proving actual allocation respects the cap.
Hoshe finding 2: submit_step_canvas coalescing now has the same two
regression tests its submit_window sibling always had (same-key
collapses to one pending item, different-key does not), exercising
step_canvas_supersede_key.
Targeted suites green: 1928 lib, acceptance gate 5/5, bridge_tcp 22/22,
window_derivation_golden 6/6 byte-green.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Two needless mutable borrows in the serve system, one spurious
markdown list marker from a doc-comment line wrap (a leading '- '
turned the whole T-1186 convention note into a lazy continuation), and
a named row/col pair replacing the identity-op grid index in the
settlement-id tie test.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The D-225-discharging wire migration per D-255(c): a new
server/src/atlas/step_canvas.rs subsystem (six-rung StepCanvasRung
ladder — Global variable-extent rung 0 through Chunk 64m — the
StepCanvasRequest/StepCanvasResponse tagged envelope extending the
proven ShapeProbe discriminated-shape pattern, PNG-per-field dense +
MessagePack-native sparse encoding per the T-1179 measured table, and
both server cache tiers: the structurally keep-always GlobalTierCache
and the dual-axis StepCanvasCache with storage TTLs per rung and
SIM_STATE_TTL clock-bucket staleness per the D-227 amendment (1)
formula). Wired through bridge/{mod,tcp,local}.rs (sixth demux shape,
send_step_canvas_response mirroring the five existing senders),
gen_queue.rs (DeriveStepCanvas work item with per-connection-per-rung
coalescing, reusing the shared TerrainAnalysisCache), and plugin.rs
(serve/complete systems, lazy D-206 rung-0 population).
Acceptance gate (mandatory per D-227 amendment (3)):
tests/step_canvas_acceptance_gate.rs — cache-hit == cache-miss
byte-identical for every rung, lossless encode round-trips, cache
round-trips vs fresh derive, distinct-center sanity. 5/5 pass.
Station-spacing cap ADOPTED: course stations floored to District
spacing (2,048 m) at finer rungs — the S2-measured +38-87% chunk/block
course cost had zero display benefit at the same station density
(COURSE_STATION_SPACING_FLOOR_M).
Documented honest gaps, not shortcuts: settlement_id is a proximity
approximation (no footprint polygons exist yet); glaciation/flooded_q
sim-state planes are wire-shape-ready D-253 stubs; rung-0 uses signed
equator-anchored rows (the canonical D-256 core convention — T-1186's
wrong-latitude behavior applies unchanged and unfixed here, by
instruction).
Legacy district_window carrier byte-unchanged: window_derivation_golden
6/6 byte-identical, all district_window suites pass unmodified. Full
suite at implementation time: 2127 passed across 45 binaries.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
jpmschweitzerandClaude