Fog of war: underground is black until the bot has seen it (t8)

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

src/sim/fog.js

@@ -0,0 +1,35 @@
+// Exploration only: never changes grains or the random stream.
+const FOG = 2;
+let fog, FW, FH;
+function fogAlloc() { FW = Math.ceil(W / FOG); FH = Math.ceil(H / FOG); fog = new Uint8Array(FW * FH); }
+function fogMark(x, y, v) {
+  if (x < 0 || y < 0 || x >= W || y >= H) return;
+  const i = Math.floor(y / FOG) * FW + Math.floor(x / FOG);
+  if (v > fog[i]) fog[i] = v;
+}
+function fogSeen(x, y) {
+  if (x < 0 || y < 0 || x >= W || y >= H) return 255;
+  return fog[Math.floor(y / FOG) * FW + Math.floor(x / FOG)];
+}
+function fogInit() {
+  for (let x = 0; x < W; x++) for (let y = 0; y < Math.min(H, surfY[x] + 8); y++) fogMark(x, y, y <= surfY[x] ? 255 : (surfY[x] + 8 - y) * 255 / 8);
+}
+function fogLook(cx, cy) {
+  for (let a = 0; a < 256; a++) {
+    const dx = Math.cos(a * Math.PI / 128), dy = Math.sin(a * Math.PI / 128);
+    let hit = -1;
+    for (let d = 0; d < 48; d++) {
+      const x = Math.floor(cx + dx * d), y = Math.floor(cy + dy * d);
+      if (x < 0 || y < 0 || x >= W || y >= H) break;
+      const ph = PH[mat[y * W + x]];
+      if (hit < 0 && (ph === PH_SOLID || ph === PH_POWDER)) hit = d;
+      const v = Math.min(255, (48 - d) * 255 / 8, hit < 0 ? 255 : (4 - d + hit) * 255 / 4);
+      if (v <= 0) break;
+      fogMark(x, y, v);
+    }
+  }
+}
+function fogRevealAround(x, y, r) {
+  for (let yy = Math.max(0, Math.floor(y - r)); yy <= Math.min(H - 1, y + r); yy++) for (let xx = Math.max(0, Math.floor(x - r)); xx <= Math.min(W - 1, x + r); xx++) if ((xx - x) ** 2 + (yy - y) ** 2 <= r * r) fogMark(xx, yy, 255);
+}
+function fogRevealAll() { fog.fill(255); }

src/sim/save.js

@@ -25,7 +25,7 @@ function serializeWorld() {
     pipes: (() => { if (pipesDirty) rebuildPipes(); return pipeNets.filter(pn => pn.n > 0).map(pn => [pn.blocks[0], pn.m, pn.n, Math.round(pn.T)]); })(),
     cols: { surfY: Array.from(surfY), dirtY: Array.from(dirtY), graniteY: Array.from(graniteY), basaltY: Array.from(basaltY), magmaY: Array.from(magmaY) },
   };
-  return { meta, buffers: { mat: mat.slice(), temp: t16, life: life.slice(), flags: flags.slice(), part: part.slice(), blockP: blockP.slice(), blockV: blockV.slice(), bgm: bgm.slice() } };
+  return { meta, buffers: { fog: fog.slice(), mat: mat.slice(), temp: t16, life: life.slice(), flags: flags.slice(), part: part.slice(), blockP: blockP.slice(), blockV: blockV.slice(), bgm: bgm.slice() } };
 }
 function deserializeWorld(meta, buffers) {
   if (meta.v !== SAVE_VERSION) throw new Error('This world was saved by an older version of the game and cannot be loaded.');
@@ -108,5 +108,13 @@ function deserializeWorld(meta, buffers) {
   if (!meta.specks) clearHardSpecks(true); // older saves: tidy away tiny specks of too-hard rock once
   rebuildPipes();
   for (const [b, m, n, T] of meta.pipes || []) { const id = pipeNetAt[b]; if (id >= 0) { const pn = pipeNets[id]; pn.m = m; pn.n = Math.min(n, pn.cap); pn.T = T; } }
+  if (buffers.fog && buffers.fog.length === fog.length) fog.set(buffers.fog);
+  else {
+    fogInit();
+    for (let b = 0; b < NB; b++) if (blockP[b]) fogRevealAround((b % BW) * BS + BS / 2, ((b / BW) | 0) * BS + BS / 2, 12);
+    for (const m of machines) if (m) for (let y = m.y; y < m.y + m.h; y += BS) for (let x = m.x; x < m.x + m.w; x += BS) fogRevealAround(x, y, 12);
+    for (const mo of molds) for (const i of moldCellsAt(mo.kind, mo.x, mo.y).walls) fogRevealAround(i % W, (i / W) | 0, 12);
+  }
+  fogLook(bot.x + bot.w / 2, bot.y + bot.h / 2);
   EV.length = 0;
 }

src/sim/tick.js

@@ -22,4 +22,5 @@ function simTick() {
   if (tick % 60 === 17) { marketTick(); ordersTick(); }
   if (tick % 30 === 11 && saplings.length) saplingTick();
   ghostTick();
+  if (tick % 4 === 0) fogLook(bot.x + bot.w / 2, bot.y + bot.h / 2);
 }

src/sim/world.js

@@ -39,6 +39,7 @@ function discover(m, x, y, from, how, T) {
 
 function alloc(w, h) {
   W = w; H = h; N = w * h;
+  fogAlloc();
   CW = Math.ceil(w / 32); CH = Math.ceil(h / 32); NCH = CW * CH;
   mat = new Uint8Array(N); temp = new Float32Array(N); life = new Uint8Array(N); flags = new Uint8Array(N);
   stamp = new Uint8Array(N); part = new Uint8Array(N); mach = new Uint16Array(N); digp = new Uint8Array(N);

src/sim/worldgen.js

@@ -311,5 +311,6 @@ function generateWorld(seedIn, w, h, onProgress) {
   seen = new Uint8Array(NMAT); ledger = {};
   stats.dug = stats.moved = stats.placed = stats.ignitions = stats.cast = stats.bars = 0;
   EV.length = 0;
+  fogInit(); fogLook(bot.x + bot.w / 2, bot.y + bot.h / 2);
   if (onProgress) onProgress(1);
 }