Multi-core simulation: grain movement and heat across a worker pool (t88 phase 3)

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

test/t_threads.js

@@ -0,0 +1,75 @@
+// Shared allocation, checkerboard independence, and real worker-count determinism.
+const assert = require('assert');
+const { load, flatWorld } = require('./harness');
+const { run } = load();
+flatWorld(run, 131, 129, 110);
+assert(run('[mat,temp,life,flags,stamp,part,mach,digp,noiseB,bgm,airS,netId,isPow,occ,awake,hot,hotLvl,renderDirty,powderArea,cleatMask,cleatChunks,roofDirty,blockP,blockV,slopePhase,fog,AMB,roofY].every(a=>a.buffer instanceof SharedArrayBuffer)'));
+console.log('PASS world arrays use shared memory');
+const crypto = require('crypto');
+const { enableThreads } = require('./harness');
+flatWorld(run, 192, 96, 31);
+run(`setCell(30*W+32,WATER,20,0);setCell(31*W+130,EMPTY,20,0);
+  tick++;tickStamp++;var draws=0,savedRnd=rnd;rnd=()=>{draws++;return .99};
+  var searchWork=inlineChunkWork();runChunks([1],0,searchWork);`);
+assert(run('searchWork.events.some(e=>e[1]==="liquid")'), 'fixture must defer a long search');
+run('mergeChunkWork([searchWork]);rnd=savedRnd;');
+assert.strictEqual(run('draws'),1,'resuming a liquid search must not reroll its movement chance');
+assert.strictEqual(run('mat[30*W+40]'),run('WATER'),'the resumed search finds the distant drop');
+console.log('PASS long liquid search resumes without rerolling movement');
+function setup() {
+  flatWorld(run, 387, 257, 214);
+  run(`{RS=123;WS=456;resetWeather();weather.next=1e15;seen.fill(0);ledger={};EV.length=0;for(const k of Object.keys(stats))stats[k]=0;
+    resetEconomy();nextPowerBuild=0;bot.x=185;bot.y=120;
+    const random=mulberry32(99), materials=[SAND,COAL,WATER,MAGMA,MCU,SNOW,LWOOD,STEAM,SMOKE];
+    for(let y=40;y<210;y++)for(let x=8;x<W-8;x++) {
+      if(random()<.68)continue;
+      const m=materials[(random()*materials.length)|0];
+      setCell(y*W+x,m,m===MAGMA?1450:m===MCU?1200:m===STEAM?110:20,0);
+    }
+    addMachine('wheel',40,35,0);
+    for(let x=0;x<W;x++)setCell(31*W+x,STONE,20,F_NAT);
+    setCell(31*W+W-10,EMPTY,20,0);
+    for(let x=32;x<W-10;x+=64)setCell(30*W+x,WATER,20,0);
+    for(let bx=12;bx<40;bx++)placeBlock(BP_FILTER,128,bx,48,true,{m:[SAND],inv:0});
+    for(let x=80;x<210;x++)setCell(120*W+x,COAL,1000,F_BURN);
+    hot.fill(6);hotLvl.fill(2);awake.fill(3);updateRoof();}
+  `);
+}
+function hash() {
+  const h = crypto.createHash('sha256');
+  for (const a of run('[mat,temp,life,flags,stamp,part,mach,digp,bgm,isPow,netId,awake,hot,hotLvl,powderArea,roofDirty,seen,renderDirty]'))
+    h.update(Buffer.from(a.buffer,a.byteOffset,a.byteLength));
+  h.update(run('JSON.stringify({RS,stats,EV,flyers,brokenMachines,pcells:[...pcells],powerDirty,weather,machines})'));
+  return h.digest('hex');
+}
+(async () => {
+  let expected;
+  for (const n of [0,1,2,8,8,2,1,0]) {
+    setup(); const stop = n ? await enableThreads(run,n) : null;
+    try {
+      run('for(let k=0;k<320;k++)simTick();');
+      const actual=hash();
+      if(!expected)expected=actual;
+      assert.strictEqual(actual,expected,`world and effects differ with ${n} workers`);
+      console.log(`PASS identical world and side effects with ${n} workers (${actual.slice(0,16)})`);
+    } finally { if(stop)await stop(); }
+  }
+  setup();
+  run('const forwardChunks=runChunks;runChunks=(chunks,pass,work)=>forwardChunks(chunks.slice().reverse(),pass,work);for(let k=0;k<320;k++)simTick();runChunks=forwardChunks;');
+  assert.strictEqual(hash(),expected,'chunk order within a colour must not matter');
+  console.log('PASS reversing chunks within every pass preserves all bytes and effects');
+  const {execFileSync}=require('child_process');
+  const fallback=execFileSync(process.execPath,['-e',`
+    global.SharedArrayBuffer=undefined;
+    const {load,flatWorld}=require(${JSON.stringify(require.resolve('./harness'))});
+    const {run}=load();flatWorld(run,64,64,50);
+    if(!run('mat.buffer instanceof ArrayBuffer'))throw Error('fallback allocation');
+    run('setCell(20*W+20,SAND,20,0);for(let k=0;k<60;k++)simTick();');
+    process.stdout.write(JSON.stringify(run('Array.from(mat)')));
+  `],{encoding:'utf8'});
+  flatWorld(run,64,64,50);
+  run('setCell(20*W+20,SAND,20,0);for(let k=0;k<60;k++)simTick();');
+  assert.strictEqual(JSON.stringify(run('Array.from(mat)')),fallback);
+  console.log('PASS Node ArrayBuffer fallback matches shared inline movement');
+  console.log('ALL PASS');
+})().catch(e=>{console.error(e);process.exitCode=1;});