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beezm 537bd3e048 chat2/08: southern stretch, EXPLORATION — the fragmentation knob space, diagnosed then laddered
Diagnostic first (SouthernStretchTool, ISLA_DIAG_ONLY; scratch/southern_diagnosis.md). Along
the central south profile the mask blend climbs 0.018 per 0.01 N, edge noise adds 0.03-0.06,
and the southern sinker is zero until 0.75 N then adds 0.024 per 0.01 N before the 2.5 power;
the coast sits at 0.76-0.82 N, ~0.06 N north of where the blend alone would end. The stretch
compresses the southward distance the mask sees inside a fixed feathered latitude band,
y' = yB + (y - yB)/(1 + s*ramp), texture (base noise, edge noise, latitude) untouched, so the
extended mass keeps the elevation of the rows it came from. With the sinker reading the REAL y
it cancels the stretch outright: median coast saturates at 0.83-0.84 from s = 1 to 16 and the
south stays 1-10 tiny nubs on both seeds. The lever is therefore two things - extend reach AND
hold the sinker back - and this pass couples them 1:1 (StretchSinker = true; the real-y mode is
kept as the config's other setting). Ladder chosen from the sweep, non-linear: 0.5, 1, 2, 3, 5
(peninsula / onset / few big pieces / big pieces consolidating / over-stretched sheet); 8 and 16
are indistinguishable from 5.

Topography: cells above the band take the untouched code path (fy == y), so the classify field
north of the band is bit-identical by construction. SouthernStretch.cs holds the band constants
(start 0.70 N, feather 0.05 N - fixed for the batch) and the ramp. TerrainGenConfig: SouthStretch
(the swept axis, 0 = off), SouthBandStartFrac, SouthBandFeatherFrac, StretchSinker.

Oracle, all passing: a1/a3 stretch OFF bit-identical; a3b stretch 5 north of the band
bit-identical to the task-03 dump (2.93 M cells), a4b the same at 8192 against the
terrain-curve-v1 gallery dump (46.97 M cells north of the band, 20.1 M differ below - the
relaxation); per field north bit-locked classify and render vs stretch 0 (p, p2), northern
island set invariant (q), centre is land, tag/coastline, classify == raw; ids and heights
deterministic. Batch: BatchRoot(8, "southern_stretch_explore") - 5 levels x 2 seeds
(1063685222, 999999937 - the two 07 seeds with the most mainland south of the band), lean render
(regions overlay + relief + .f32), the hemisphere-split count/size table. Region labeling on,
offshore / shelf / speck revert off: the pure fragmentation signal.

The read at 4096: s 0.5 peninsula (coast +0.04 N); s 1 onset (999999937 6 -> 12 southern islands,
11 substantial); s 2 few big pieces (35k / 86k-cell fragments); s 3-5 a solid sheet to the trench
whose southern edge is the trench wall - a ruler-straight coast - and whose island count falls as
pieces re-merge. Gravel never dominates. Graduation held, per the task.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013EY3ZTF6NwzF8ukBHQXSK7
2026-08-22 05:54:12 -04:00
Client Phase 0: clean project skeleton for the v2 rewrite 2026-08-19 20:21:12 -04:00
Core chat2/07: the region-labeling layer — label all land, tag by construction, tunable speck revert 2026-08-22 03:50:33 -04:00
Server Phase 0: clean project skeleton for the v2 rewrite 2026-08-19 20:21:12 -04:00
Tools chat2/08: southern stretch, EXPLORATION — the fragmentation knob space, diagnosed then laddered 2026-08-22 05:54:12 -04:00
.gitattributes Phase 0: clean project skeleton for the v2 rewrite 2026-08-19 20:21:12 -04:00
.gitignore Phase 0: clean project skeleton for the v2 rewrite 2026-08-19 20:21:12 -04:00
islaApocalypse-v2.csproj Phase 0: clean project skeleton for the v2 rewrite 2026-08-19 20:21:12 -04:00
islaApocalypse-v2.sln Phase 0: clean project skeleton for the v2 rewrite 2026-08-19 20:21:12 -04:00
project.godot Move the user:// isolation warning out of project.godot 2026-08-19 21:31:12 -04:00
README.md Phase 2a: the faithful redistribution curve, re-measured against v2's own output 2026-08-20 01:38:10 -04:00

Isla Apocalypse — v2

The rewrite (D-049). A post-apocalyptic survival voxel game: one island, generated once offline, loaded by everyone.

Status: Phase 2 — shaping. Phase 0 laid the contracts and the tooling rails; Phase 1 ported the crown-jewel noise and pass 1 (the island's raw shape); chat2/01 added pass 2a — the height redistribution curve and shelf detail, re-calibrated against this repo's own output, with the two-height-field split and an automatic oracle.

Still no erosion, rivers, water bodies, crater carve, coast shelf, offshore islets, biomes, roads or mesher.


⚠ Two repos. Never one.

Repo Role
~/celerNexus/islaApocalypse-v2/ (this) The rewrite. Every line of new code is written here.
~/celerNexus/islaApocalypse/ READ-ONLY. The pre-rewrite prototype, archived at ab78883, tag pre-rewrite-reference. Ported FROM; never written to.
~/celerNexus/islaApocalypse-vault-v0.1/ The design vault — the source of truth for WHAT and WHY. The vault leads.

The old codebase is a spent quarry (D-050): mined, never tracked, never synced, never canon'd. Writing rewrite code into it would corrupt the very thing being ported from.

⚠ Runtime data isolation — do not weaken

This project pins its user:// directory away from the old prototype's, which holds the preserved reference seeds, blueprints and batches:

user:// → ~/.local/share/islaApocalypse-v2/          ← this project
          ~/.local/share/godot/app_userdata/islaApocalypse/   ← ⛔ the OLD prototype. Never touch.

Pinned two ways in project.godot — a distinct application/config/name and use_custom_user_dir + custom_user_dir_name. Both must stay.

⚠ Do not document this with a comment in project.godot — it will not survive.

Godot rewrites project.godot on import and STRIPS ALL COMMENTS, replacing the header with its own boilerplate. (Measured: a warning block written there was gone after the next --import. The settings survived; only the explanation was deleted.) So the warning lives here, and the guarantee is enforced by the probe below — which exits non-zero on a clash and therefore works in a pre-flight check, not just by eye.

After any change to the [application] block, re-run the probe:

Godot_v4.7.2-stable_mono_linux.x86_64 --headless \
  --path ~/celerNexus/islaApocalypse-v2 res://Tools/Scenes/UserDirProbe.tscn

Layout

Core/     math + data only, ENGINE-FREE   — depends on nothing above it
Server/   authoritative logic             — may use Core          (empty: not yet its phase)
Client/   rendering                       — may use Core          (empty: not yet its phase)
Tools/    the offline generator           — ⚠ may NOT use Client

Each layer has a README.md stating its role and its boundary. Read the one for the layer you are about to write in — they carry the reasons, not just the rules.

The contracts this phase establishes

  • ★★ The column model (D-053) — the world as a 2D grid of columns, each a stack of (material, thickness) runs. Air is the top run; there is no air-vs-solid height branch.Core/Scripts/Column.cs
  • The material schemas (D-054) — terrain and building, two schemas bridged by a transformation seam that is deliberately empty. Identity is a registry key, never an ordinal. Mesh style is per-origin, never a material property. → Core/Scripts/MaterialRegistry.cs
  • The scaling discipline — nothing uses a raw pixel number. → Core/Scripts/GenerationScale.cs
  • The vertical yardstick — ONE metres-per-raw-unit number, not three constants and twenty literals as the prototype had. → Core/Scripts/WorldScale.cs
  • The elevation profile — the 7-band redistribution curve, identity at and below sea, its knots measured rather than chosen. → Core/Scripts/HeightCurve.cs
  • The two-height-field split (D-046) — heightClassify is raw and is the oracle; height is curved and is what gets drawn. → Tools/Scripts/Pass2Result.cs
  • Tooling safety — every path env-overridable, deletion refused by code. → Core/Scripts/ToolingPaths.cs, Core/Scripts/FileSafety.cs

Build

dotnet build
Godot_v4.7.2-stable_mono_linux.x86_64 --headless --import --path .

Godot 4.7.2 (mono) · .NET 8 (net8.0) · Godot.NET.Sdk/4.7.2

The reference repo is Godot 4.7.1. This repo deliberately targets 4.7.2 — clean rewrite, current tooling. 4.7.1 is the port source, not a constraint on new code.

<RollForward>Major</RollForward> in the .csproj is load-bearing.

The target is net8.0 but this machine carries only a .NET 10 runtime. Without that property the generated runtimeconfig.json rolls forward by MINOR only and every run fails with "You must install .NET 8". This bites at run time, not build time — the build succeeds either way — so re-check the emitted runtimeconfig.json after any .csproj change.

What this phase is NOT

No mesher, no stratigraphy, no biomes, no water, no rivers, no erosion. The pipeline is 2D-maps-first (D-056): stages 15 are flat maps, gotten completely right before a single 3D vertex exists. Building the mesher before the data is right is the specific trap this rewrite exists to undo.

And the curve is a BASELINE, not a verdict. It is ported faithfully and calibrated honestly so that later reshaping has a control to be judged against. Whether this elevation profile — 60 % of land in the bottom 14 m, 4 % above the plateau — is the one the world wants is an open question the histograms exist to inform, not one this port has answered.