Cooled magma is ordinary rock: visible in the smooth look and drillable

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

docs/DESIGN.md

@@ -517,6 +517,10 @@ above, including:
   and warned about before it happens (a glow near the limit). A heat-resistant screw comes later
   as an upgrade. Prompted by a long vertical screw that seemed to leak for no reason while it
   carried hot rubble.
+- **Melts that cool loose are ordinary rock (2026-10-27).** Magma poured from the bag became an
+  invisible, undrillable basalt the game treated as built. Now any melt except metal and glass
+  cools into natural rock wherever it came from, and any solid no block, mold or machine owns can
+  be drilled, so nothing can get permanently stuck in the world.
 
 ## Ideas not built yet
 

docs/agent-log.md

@@ -4,6 +4,19 @@ What agents have done, newest first. Add an entry for every piece of work: the d
 note or request it was for, what changed, the files touched, the tests run, and anything left
 open or not verified. Keep each entry short; the git history has the details.
 
+## 2026-10-27: cooled magma visible and drillable (Claude Code)
+
+- Owner report: bag magma in a brick box left invisible basalt that couldn't be picked up,
+  drilled or built on; melted screws left similar bits. Cause: melts froze into non-natural
+  rock unless the liquid was natural, the drill only breaks natural rock, and the smooth look's
+  terrain field skipped non-natural solids.
+- `src/sim/heat.js`: non-metal, non-glass melts freeze into natural rock; bag water into natural
+  ice. `src/sim/drill.js`: `crumbly` no longer needs F_NAT; `builtCell` protects slope corner cells.
+  `src/render/world.js`: the terrain field covers any terrain-class solid without a block or
+  machine. Note: the bot still passes through old stuck basalt until it is drilled (it only
+  collides with natural solids).
+- Tests: 7 checks in `test/t_drill.js`; `python3 test/run_all.py --browser` all passed.
+
 ## 2026-10-27: t67 phase 4, "doesn't connect" marks (Claude Code)
 
 - `nearMiss(bx, by, end, planned)` in `src/sim/joins.js`: an end with no join that would join

src/render/world.js

@@ -291,7 +291,7 @@ function drawWorld() {
             ((y - ((wb / BW) | 0) * BS + 8) << 16) | ((x - wb % BW * BS + 8) << 8);
         }
         top = cl << 24;
-        fpx[row + bx] = (tb ? 0xff000000 : 0) | (cl === 5 ? 0xff0000 : 0) | (cl === 3 ? 0xff00 : 0) | (cl === 1 && !builtForLight(i, x, y) ? 0xff : 0);
+        fpx[row + bx] = (tb ? 0xff000000 : 0) | (cl === 5 ? 0xff0000 : 0) | (cl === 3 ? 0xff00 : 0) | (cl === 1 && !blockP[(y >> 2) * BW + (x >> 2)] && !mach[i] ? 0xff : 0); // terrain: any solid nothing owns, natural or not
       }
       if (fv < 255) {
         const k = fv / 255; r *= k; g *= k; b *= k;

src/sim/drill.js

@@ -28,7 +28,7 @@ function pulseRay(ox, oy, ang, Wd, f) {
 }
 // Is a solid cell something the player built (or a part of a machine or mold)? Pulses leave those alone.
 function builtCell(i, x, y) {
-  return PARTMAT[mat[i]] || part[i] || mach[i] || blockP[((y / BS) | 0) * BW + ((x / BS) | 0)] !== 0 || (!(flags[i] & F_NAT) && moldAt(x, y) !== null);
+  return PARTMAT[mat[i]] || part[i] || mach[i] || blockP[((y / BS) | 0) * BW + ((x / BS) | 0)] !== 0 || slopeSealOwner(i) >= 0 || (!(flags[i] & F_NAT) && moldAt(x, y) !== null);
 }
 // One press-and-hold step: fires a pulse when one is due. Returns { fired, status }.
 function toolPulse(ax, ay, width, tune) {
@@ -86,7 +86,8 @@ function crumbleAround(x, y) {
     for (const j of got) shatterCell(j, j % W, (j / W) | 0, mat[j]);
   }
 }
-function crumbly(i) { const m = mat[i]; return PH[m] === PH_SOLID && (flags[i] & F_NAT) !== 0 && YLD[m] !== 0 && HARD[m] <= BIT_TIERS[player.bitTier].hard && !builtCell(i, i % W, (i / W) | 0); }
+// Any solid nothing owns can be drilled: natural rock, and rock or metal that set loose in the world.
+function crumbly(i) { const m = mat[i]; return PH[m] === PH_SOLID && YLD[m] !== 0 && HARD[m] <= BIT_TIERS[player.bitTier].hard && !builtCell(i, i % W, (i / W) | 0); }
 function shatterCell(i, x, y, m) {
   const to = YLD[m];
   setCell(i, to, temp[i], 0);

src/sim/heat.js

@@ -130,7 +130,7 @@ function react(i, x, y, m) {
       if (rnd() < 0.02 - t * 0.004) {
         const below = y < H - 1 ? PH[mat[i + W]] : PH_SOLID;
         const to = below === PH_EMPTY || below === PH_GAS ? SNOW : ICE;
-        mat[i] = to; life[i] = 0; flags[i] = fl & F_NAT; wakeXY(x, y); discover(to, x, y, WATER, 'freeze', 0);
+        mat[i] = to; life[i] = 0; flags[i] = to === ICE ? F_NAT : fl & F_NAT; wakeXY(x, y); discover(to, x, y, WATER, 'freeze', 0);
       }
       return;
     }
@@ -143,7 +143,8 @@ function react(i, x, y, m) {
         if (L <= 0) {
           const to = FRZTO[m];
           mat[i] = to; life[i] = 0; temp[i] = fz - 1;
-          flags[i] = (fl & F_NAT) | (CASTMETAL[m] ? F_CAST : 0); // natural magma freezes into natural rock
+          // metal and glass set into castings; any other melt cools into ordinary rock you can drill, wherever it came from
+          flags[i] = CASTMETAL[m] ? (fl & F_NAT) | F_CAST : PH[to] === PH_SOLID ? F_NAT : fl & F_NAT;
           wakeXY(x, y); discover(to, x, y, m, 'freeze', fz);
         } else { life[i] = L; temp[i] = fz; }
         return;

test/t_drill.js

@@ -139,4 +139,36 @@ run('for (let y = 80; y < 100; y++) for (let x = 120; x < 122; x++) bgm[y * W +
 hold(121, 92, 1, 0, 3);
 check('a tree trunk in the path is cut into wood chunks', count(run, run('LWOOD')) > 0, count(run, run('LWOOD')));
 
+// Melts that cool loose in the world (magma from the bag, metal spilled outside a mold) are
+// ordinary solids the drill can break; built walls, slope corner cells and molds stay protected.
+flatWorld(run, 160, 128, 120);
+const melt = run(`(() => {
+  player.bitTier = BIT_TIERS.length - 1; bot.x = 60; bot.y = 60;
+  for (let y = 80; y < 88; y++) for (let x = 60; x < 72; x++) setCell(y * W + x, MAGMA, 1250, 0);
+  for (let k = 0; k < 2400; k++) simTick();
+  for (let x = 90; x < 96; x++) setCell(110 * W + x, COPPER, 20, F_CAST); // metal that set outside a mold
+  let bas = 0, nat = 0, cu = 0, drillable = 0, cuDrill = 0;
+  for (let i = 0; i < N; i++) {
+    if (mat[i] === BASALT) { bas++; if (flags[i] & F_NAT) nat++; if (crumbly(i)) drillable++; }
+    if (mat[i] === COPPER) { cu++; if (crumbly(i)) cuDrill++; }
+  }
+  return { bas, nat, drillable, cu, cuDrill };
+})()`);
+check('magma from the bag cools into natural basalt', melt.bas > 0 && melt.nat === melt.bas, JSON.stringify(melt));
+check('that basalt can be drilled', melt.drillable === melt.bas, JSON.stringify(melt));
+check('copper that set outside a mold can be drilled for scrap', melt.cu > 0 && melt.cuDrill === melt.cu, JSON.stringify(melt));
+check('basalt already stuck without the natural mark can be drilled too',
+  run('(() => { setCell(20 * W + 20, BASALT, 20, 0); player.bitTier = BIT_TIERS.length - 1; return crumbly(20 * W + 20); })()'));
+check('built walls and slope corner cells stay safe from the drill', run(`(() => {
+  placeBlock(BP_WALL, RSTONE, 5, 5, true); placeBlock(BP_SLOPE_BL, RSTONE, 8, 5, true);
+  const wallCell = 5 * BS * W + 5 * BS + 1; let seal = -1;
+  for (let i = 0; i < N; i++) if (slopeSealOwner(i) >= 0 && PH[mat[i]] === PH_SOLID) { seal = i; break; }
+  return !crumbly(wallCell) && (seal < 0 || !crumbly(seal));
+})()`));
+check('a mold and what sets inside it stay safe from the drill', run(`(() => {
+  bag[RSTONE] = 400; bagTotal = 400; const err = placeMoldAt('ingot', 30, 10, RSTONE);
+  const mo = molds[molds.length - 1]; if (err || !mo) return false;
+  for (const i of moldCellsAt(mo.kind, mo.x, mo.y).walls) if (crumbly(i)) return false;
+  return true;
+})()`));
 done();