Lakes fill only to their lower rim and keep clear of spawn and the dock (t96)

The lake lip was Math.min(surfY), the highest ground (y grows downward), so water was poured
above the lower rim and, once levelled, ran up to the trade dock on 4 of 12 seeds. The lip is
now the lower rim edge minus one, and each lake stays 80 grains from spawn. Seed hashes and
the shallow-ore hash re-baselined (changes only under lake basins); golden fixtures also
freeze surfY/dirtY/AMB from the previous generator.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

test/t_corner_seal.js

@@ -4,11 +4,11 @@ const { createHash } = require('node:crypto');
 const { run } = load();
 const { check, done } = suite();
 
-// t96 re-baseline: only the generation lake-levelling pass changes these material bytes.
+// t96 re-baseline: only lake generation (rim height, spawn clearance, levelling) changes these material bytes.
 for (const [seed, expected] of [
-  [777, '1fac6b4b6420f328d7de87c0813e328303271e7605d85ce541e108361aff0d90'],
-  [77, 'de3ec38547585486924f53abb82cb3c0f76e0bd24b75873ddf96599b5886b52a'],
-  [4242, '57cd89b5518c3e342fc1b91243cd068dc2e38a2d42de84a1c2ee1cbf936c2f1a'],
+  [777, '7d60a0f1a92b42438471c8c15c5cc92576a75a4aa54b8c519c42904acb7088a6'],
+  [77, '724eb1730ca5fead6aeaa13994beb2e066bb9d65c7db7e0b790857e2d72b7c2a'],
+  [4242, '9ffdabf1ffe8ab6cd5855ccfe05c31221d1a0517d960bf2e2273018e9dbf03f9'],
 ]) {
   run(`generateWorld(${seed}, 512, 384)`);
   check(`seed ${seed} restores corner sealing`,run('CORNER_SEAL')===true);

test/t_lakes.js

@@ -17,11 +17,14 @@ function surfacePools() {
   })()`);
 }
 for (const [seed, expected] of [
-  [7, '669a4ee87496be27473d2987d9a8935be1a19b29a8f2433d306f32a1616f3bca'],
-  [42, 'efeadd2bff0ce3eaf81e5a08a998ce767e9667e3b27b8623e928f202669f640e'],
-  [424242, '24b5e6ccc4e7d5eb9d54c3ff0fa5dfe84185b83e75b07261ac007b4f920f0640'],
+  [7, '4c4778417e6cf6e9577b831e66111bd374068a14e15642bae304b8a45a68b879'],
+  [42, '907f2ed79b9fda1ae99c5ee55fa19ce85eff8ffdcd7dadac14a2deb42223217d'],
+  [424242, '40080ea6039d0d4247e36fd9a5837d0675100414f198d77419ecf500c7f9d6ad'],
   [2, null],
   [1, null],
+  // Before t96 round 3 these lakes ran over their lower rim up to the trade dock.
+  [5, null],
+  [6, null],
 ]) {
   run(`generateWorld(${seed}, 2048, 1024, (f, label) => {
     if (f === 0.99 && label === 'Finishing') globalThis.waterBeforeLevel = mat.reduce((n, m) => n + (m === WATER), 0);
@@ -33,6 +36,8 @@ for (const [seed, expected] of [
   check(`seed ${seed} conserves water through levelling`, run('mat.reduce((n, m) => n + (m === WATER), 0) === waterBeforeLevel'));
   const initial = surfacePools();
   check(`seed ${seed} starts with flat surface pools`, initial.length > 0 && initial.every(p => p.max - p.min <= 1), JSON.stringify(initial));
+  check(`seed ${seed} keeps its lakes clear of the trade dock`, run(`(() => { const d = machines.find(m => m && m.type === 'dock');
+    return ${JSON.stringify(initial)}.every(p => p.x1 < d.x - 8 || p.x0 > d.x + 24 + 8); })()`), JSON.stringify(initial));
   check(`seed ${seed} restores pinned generation switches`, run('LSTEP === 8 && LFILM === 4 && SORTP === 0.06 && CORNER_SEAL && POWDER_FAN'));
   check(`seed ${seed} starts every water area awake`, run(`mat.every((m, i) => m !== WATER || awake[((i / W) >> 5) * CW + ((i % W) >> 5)] > 0)`));
   check(`seed ${seed} has no submerged tree base`, run('treeBases.every(i => !treeHeld(i) || mat[i] !== WATER)'));

test/t_lakes.py

@@ -47,7 +47,7 @@ with launch(viewport={'width':1280,'height':760}) as (_, pg, url):
         pools=pg.evaluate(measure)
         assert pools and all(p['max']-p['min']<=1 for p in pools),pools
         print(state,result,pools,flush=True)
-        assert result['n']>300 and result['hi']-result['lo']<=1 and result['wet']==0
+        assert result['n']>150 and result['hi']-result['lo']<=1 and result['wet']==0
         pg.evaluate('snapCamera();renderDirty.fill(1);')
         pg.wait_for_timeout(300)
         pg.screenshot(path=str(ROOT/f'shots/t96-{state}-settled.png'))

test/t_world.js

@@ -185,7 +185,8 @@ oreNames.forEach((name, j) => {
 });
 const totalOre = oreBalance.counts.reduce((a, b) => a + b, 0);
 check('total ore is about 4 to 4.5 times the original', totalOre >= 162519 * 4 && totalOre <= 162519 * 4.5, totalOre);
-check('shallow ore matches the original generator', oreBalance.shallowHash === 706875613, oreBalance.shallowHash);
+// t96 round 3: lake basins moved, so ore under them changed (414 cells, all under the two lakes).
+check('shallow ore matches the original generator', oreBalance.shallowHash === 607138519, oreBalance.shallowHash);
 run('generateWorld(99, 4096, 1536, null)');
 const marks = run('(()=>{let lakes=0,peaks=0,inLake=false;for(let x=1;x<W-1;x++){const l=mat[(surfY[x]-1)*W+x]===WATER;if(l&&!inLake)lakes++;inLake=l;if(surfY[x]<surfBase-100&&surfY[x]<=surfY[x-1]&&surfY[x]<surfY[x+1])peaks++;}return [lakes,peaks]})()');
 check('a large world has several lakes and mountains across it', marks[0] >= 2 && marks[1] >= 2, marks);