Choose the river count against the terrain that actually exists. The M3 count of
3 was tuned on topography the southern stretch (D-065) and coastal fragmentation
(D-063) have since replaced, and TrunkCount/GiantCount/EndorheicMaxCount = 3 are
LEAN REPORTING CAPS, not a statement about this island.
UNIFIED RANKING. The reference promoted from two lists with two quotas — N sea
trunks, N endorheic giants — which encodes the assumption that reaching the sea
is what makes a drainage a river. This terrain does not satisfy it: 54-78% of
land drains inland across the gallery, 106-121 terminal basins per seed. So
selection is unified — every major drainage ranked by contributing-cell count in
ONE list, top N promoted, and the sea/endorheic split FALLS OUT. A quota would
have promoted small coastal drainages over far larger inland ones purely because
of where they end. Deliberate departure from the reference's structure (D-050
noted, approved in chat). Only SELECTION is unified: the per-terminus tag is
retained per river because rivers/03's routing branches on it, and Trunk/Giant
are untouched.
The metric is the same unit on both sides, and that is now ASSERTED rather
than argued: sea Acc and endorheic BasinInflow are both counts of contributing
land cells on the same D8 field, and every land cell has exactly one
destination, so Σ sea Acc + Σ BasinInflow + unrouted == LandCells exactly. The
tool refuses to rank unless it holds, per seed. It held on all 8.
DrainageAnalysis.cs is NOT modified. The complete candidate set is re-derived
from state it already exposes (Dir/Acc/BasinId/BasinInflow/FullFilled); the
three internal per-basin values that are not exposed are exactly reconstructible
because terminal basins are reverted to the real surface while FullFilled keeps
the fill. Only REPORTING caps were raised, and only so the analysis's own
TraceStem produces a real upland course per promotable candidate.
EndorheicMinDepthM/MinAreaPx were left alone — they decide which depressions
BECOME terminal basins, i.e. they define the routing surface itself, and a count
chosen on a moved surface would be a count for terrain that does not exist.
TWO FINDINGS.
1. THE TERRAIN HAS NO NATURAL COUNT. The knee (largest ratio between
consecutive ranks) lands at rank 19/7/15/5/4/12/3/8 across the eight
gallery seeds at ratios of 1.33-1.57x, with one uncorroborated 2.37x. A
break that wanders across the whole plausible range at that strength is not
a break — on a log axis the candidates fall on a near-straight line.
N is a DESIGN choice, and the diagnostic says so instead of inventing one.
2. THE ISLAND'S MAJOR RIVERS ARE INLAND RIVERS. Six of eight seeds have ZERO
sea-reaching drainages in their top 8; the median at N=16 is one; one seed
has none at 16. On the primary seed the largest sea drainage ranks 11th at
736,088 px against 2,329,573 px for the largest endorheic — 3.2x. (That
outlet is exactly batch 12's recorded top trunk, to the cell.)
A concern I raised and then CLOSED by measuring: MinOutletSeparationPx is a
plain Euclidean test with no notion of which landmass a coastline belongs to, so
on a fragmented archipelago it could suppress an island's only river. Measured:
0-6 cross-landmass suppressions per seed, and — decisively — the largest
suppressed above-floor outlet anywhere is 209,611 px against a smallest ladder
cutoff of 439,592 px, so ZERO suppressed outlets clear any rung on any seed. The
rule provably cannot have altered the ladder. Real but harmless; flagged for
rivers/03, not a blocker. The rule was NOT changed — it belongs to the analysis,
and moving it would move the candidate set the developer is being asked to judge.
Also found: the params are ABSOLUTE pixel counts, so this analysis is only valid
at the size they were tuned for. At 1024 nothing qualifies as endorheic (the
whole endorheic half cannot be exercised) and separation suppresses 15,043 of
15,048 outlets. The tool now refuses loudly to have a non-8192 run read as a
count decision. Flagged for rivers/03: these want to become scale-free fractions
as MinLandComponentFrac already is.
Giant.ProvisionalRoute is never rendered — the "comb" is rivers/03's to replace,
and drawing it would make a count judgment look like a finished network. The
plates draw the real erosion-carved upland stems. Endorheic rivers are marked at
where their stem POOLS, not at the basin's deepest cell: the analysis
distinguishes these deliberately and they sit up to 395 px apart, which drew
every stem detached from its own endpoint until it was fixed.
TASTE GATE: 8/12/16 are presented and nothing is decided. No count is chosen, no
default is set, and neither TerrainGenConfig nor DrainageAnalysis.Params changed.
-> XX_Human/output/rivers/02_promotion.report.md
-> batches/rivers/02_promotion/INDEX.md
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WhkXBQh2tDmcWKpXYcj8vj
Core/Scripts/DrainageAnalysis.cs is the reference's DrainageAnalysis ported verbatim: the
Barnes priority-flood routing fill (8-connected, seeded from the four borders, index
tiebreak, pit fills ONE ULP above the parent so every filled cell keeps a strictly
descending path to its spill; the terrain heightmap itself is never written - the fill lives
in its own array), terminal-basin qualification (depth >= 2 m AND area >= 10,000 px; the rest
are pits filled through), D8 flow directions on the routing surface - FOR ANALYSIS ONLY, the
reverted-as-carving landmine stated in the file - Kahn accumulation, the memoised destination
walk crediting a terminal basin with TOTAL inflow, sea-reaching outlets ranked by drainage
area with the outlet separation, main stems by max accumulation, mountain exits from the
along-stem grade, lean tributaries, lean endorheic terminals, and the promoted giants
(provisional routes computed as the reference did, not drawn - routing is a later task).
WorldScale-denominated; Dir / Acc / Filled / FullFilled / BasinId / BasinInflow exposed so the
caller can prove the invariants.
"The sea" is the OCEAN body from the region layer: RegionLabeling.OceanMask - the 4-connected
water component touching the border, on the CLASSIFY field (the water-side complement of the
land contract). Enclosed lagoons, lake beds and island-fringe pockets are ordinary terrain to
the router.
DrainageTool (4 task-11 seeds at 8192, the eroded fields bit-identical to the 11 dumps)
renders the log-scaled accumulation map and the promoted-candidates overlay (trunks cyan,
endorheic giants orange, lean terminals red; nothing carved) and writes the accumulation
.f32. Oracle, all passing: render AND classify fields bit-identical before/after the analysis
(zero terrain cells written), no water added, full fill >= original everywhere with a
non-ascending path to the border from every cell, ocean mask all below sea and on the border,
dir/acc/candidates identical across two runs.
Endorheic basins are the expected first-class output: on every seed the top giants out-drain
the top trunks - the biggest drainages pool inland because erosion delivers the upland network
only and cannot cross the flats.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013EY3ZTF6NwzF8ukBHQXSK7
