Jeroen: 'still not filling the screen... maybe we should calculate the depth
that needs to be invented based on the canvas size somehow.' That is the fix.
The old flow picked cells from the viewport, let the SERVER impose Global's
2:1 aspect, then fitted the returned extent into the drawable area with an
INTEGER pixels-per-gridunit ratio. When that extent did not divide the area
evenly, floor() dropped a whole step — and at ratio 2 the only step below is
1, i.e. half size. Worse, because the client fitted an extent it had not
chosen, the result could fill NEITHER axis.
Inverted: global_fill_extent() chooses the cell count FROM the ratio, already
shaped 2:1, so cells * RATIO is the drawn size by construction and lands
exactly on the binding axis. Verified across window shapes — 1920x1080 fills
width, 2560x1080 fills height, 2560x1440 width, 3440x1440 height, 1280x720
width. Exactly one axis fills at every shape, which is the most a 2:1
equirectangular canvas can do in an arbitrary viewport; the other letterboxes.
Global keeps its 2:1 aspect because it is 360 degrees of longitude by 180 of
latitude — the aspect cannot follow the viewport without shearing the map.
Tests pin the invariant directly: 2:1 preserved, never overflowing the
drawable area, and never leaving slack on BOTH axes.
Client suite 1832 / 1806 passed / 0 failed / 26 skipped.
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>
DISPLAY_RATIO_DEEP 1.0 -> 2.0, so a viewport-fit request at District/
Quarter/Block/Chunk asks for ~4x fewer gridunits (1920x1080: ~2.07M
cells -> ~518K) and the server-side derive cost falls with it. Texel-
exactness is preserved — the ratio stays a whole number of screen px
per gridunit, so every source texel still lands on whole pixels; only
the block size changes. Non-integer ratios are not an option here:
they reintroduce exactly the sub-pixel blur D-255's texel-exactness
exists to prevent.
Judged live by Jeroen against the 1x1 build (pair session): the deep
rungs read as crisp larger pixels rather than blur, and the speedup is
substantial. Looks were the gate.
Both transport tests that pinned the old literal now assert the
RELATIONSHIP instead — deep rungs share the constant, viewport-fit
divides by it — plus a new guard that the ratio stays whole, so the
value remains tunable without editing tests that are not about it.
Co-Authored-By: Claude <noreply@anthropic.com>
The fractional fit branch is deleted, resolving both review findings at
the root: tyre showed its comments cited D-255 for an exception the
record does not contain (the language came from the lead's ticket text,
not governance), and hoshe showed it returned sub-1x for a canvas
exceeding the viewport on one axis. Replacement: fit_scale_ratio()
chooses the largest integer pixels-per-gridunit R fitting both
legend-reserved axes, floored at 1 (over-viewport draws native and
crops like every fixed rung) — the fine-grained integer lattice (GJ1c
1080p -> 9px/gu = 1593x792, ~98% width; 4K -> 20) that makes the
fractional hatch unnecessary. center_offset() floors to whole pixels
(half-pixel centering would blur the texel grid). Doc comments cite the
real sanction (D-255 amendment 2026-07-25, this branch). Legend column
constant is now canonical in transport, read directly by the legend
(was an independently-typed literal); its test asserts real geometry.
New regression test proves _global_body_extent clears on body switch
and never caps another body's requests.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The two client fixes for the Atlas frames Jeroen flagged. Region rung no
longer requests more planet than exists: cap_extent_to_body() caps the
viewport-fit extent at the body's own region grid (the Global canvas
extent echo — cols=regions_per_equator, rows=cols/2), matched by gridunit
SPACING not rung name, applied before the request/cache key is built;
cold-start scroll-before-Global-echo requests uncapped and lets the
server clamp (documented). Kills both the side-by-side continent repeat
and the past-the-pole stripe smear.
Global opener now fit-scales and centers through one shared letterbox
mechanism (center_offset/integer_fit_scale/fit_scale, 75%-coverage
integer-vs-fractional decision, NEAREST already forced on orbital rungs
per D-255's escape hatch) also used for the Region cap's letterbox
remainder. Legend column reserved before fitting — pinned to the legend's
own width by a cross-constant test, never overlapping the canvas.
Also fixes a latent crash: NOTIFICATION_RESIZED fires mid-_ready() before
children exist; null guard in the resize path.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The two-layer client rebuild per D-255(a)(b)(e), replacing the
_canvas.scale continuous-zoom model with one viewer, one path, all six
rungs:
- step_canvas_protocol.gd: StepCanvasRequest/Response codec against
the T-1181 wire contract — incl. the discovered png_bytes subtlety
(rmp_serde without serde_bytes emits a msgpack int-array, not bin;
decode repacks via PackedByteArray before load_png_from_buffer) and
the extent-echo rule (read the server-clamped extent, never assume
the requested one).
- step_canvas/ component: transport (six-rung ladder, cursor-anchored
scroll steps, edge-scroll/WASD pan with re-request on edge crossing,
hard reset-to-Global), RTT terrain layer (Image.set_pixel colorize
per the c1 measured ruling, texture.update reuse on step-cross,
NEAREST coarse / LINEAR fine per rung), unscaled screen-space
annotation sibling (courses + settlement markers at literal px),
in-memory LRU cache (Tier 1; T-1183 layers the disk tiers beneath),
request lifecycle (pending retry, staleness gate, extent echo).
- Full _canvas.scale retirement in the same change: the zoom-scaled
canvas model, the _zs compensation family, select_rung /
MAX_COVERAGE_M / compute_tile_grid, the orbital-mosaic-vs-window
two-path split, _view_zoom/_canonical_fit_zoom — 10 source files
deleted; their 14 test suites deleted with them (T-1157 dead-goldens
rule; replacement visual-capture coverage is re-scoped T-1157).
- Surviving surfaces kept per the ticket: atlas_window_cache.gd's LRU
shape (the ticket's named file atlas_window_tile_set.gd was the
retiring orchestrator; the real LRU shape lives in
atlas_window_cache.gd — cited in step_canvas_cache.gd), overlay
colors, legend/overlay-bar chrome, AtlasViewer descend geometry.
Determinism boundary per D-255(e): the client interpolates only within
the closed server-supplied input set. 7 new gdUnit suites (164 cases)
incl. a real extent-echo bug caught by its own test during
implementation. Full client suite green (exit 0) with the live-gated
suites running against a worktree server build.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
jpmschweitzerandClaude