Screw tubes carry bars, one whole bar at a time

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

src/sim/conveyors.js

@@ -106,6 +106,7 @@ function tubeSpread(c, x, y, sx, sy, intake = false) {
 // An empty screw cell draws in loose material from behind it or from its sides
 // (not from the cell it pushes into), so a tube end sitting in a pile feeds itself.
 function tubeIntake(i, p, dx, dy) {
+  if (occ[i]) return;
   const x = i % W, y = (i / W) | 0;
   const cands = [[-dx, -dy], [dy, dx], [-dy, -dx]];
   const start = (tick + i) % 3;

src/sim/items.js

@@ -32,41 +32,107 @@ function spawnBar(m, x, y, vx, vy, T) {
   return e;
 }
 function removeEnt(e) { entMark(e, 0); const k = ents.indexOf(e); if (k >= 0) ents.splice(k, 1); }
+// No transient tube state: even a loaded bar derives its ride from its eight cells.
+function entTubeAt(x, y) {
+  if (x < 0 || y < 0 || x + BAR_W > W || y + BAR_H > H) return 0;
+  for (let yy = y; yy < y + BAR_H; yy++) for (let xx = x; xx < x + BAR_W; xx++) {
+    const p = part[yy * W + xx]; if (p < P_TU || p > P_TR) return 0;
+  }
+  return part[(y + 1) * W + x + 1];
+}
+function entTubeFree(x, y, tubeOnly = false) {
+  if (x < 0 || y < 0 || x + BAR_W > W || y + BAR_H > H) return false;
+  for (let yy = y; yy < y + BAR_H; yy++) for (let xx = x; xx < x + BAR_W; xx++) {
+    const j = yy * W + xx, p = part[j], tube = p >= P_TU && p <= P_TR;
+    // gas and liquid don't stop a bar, in a tube or in the open
+    if (occ[j] || (mat[j] !== EMPTY && PH[mat[j]] !== PH_GAS && PH[mat[j]] !== PH_LIQUID) || (tubeOnly ? !tube : !tube && entSolidCell(j))) return false;
+  }
+  return true;
+}
+// Check the swept rectangle too: a snap must never jump through a grain or another bar.
+function entTubeMove(e, x, y, tubeOnly = false) {
+  if (!entTubeFree(x, y, tubeOnly)) return false;
+  for (let yy = Math.min(e.iy, y); yy <= Math.max(e.iy, y); yy++)
+    for (let xx = Math.min(e.ix, x); xx <= Math.max(e.ix, x); xx++) if (!entTubeFree(xx, yy)) return false;
+  e.x = e.ix = x; e.y = e.iy = y; e.vx = e.vy = 0; return true;
+}
+function entTubeEnter(e, dx, dy) {
+  for (let k = 0; k < (dx ? BAR_H : BAR_W); k++) {
+    const xx = e.ix + (dx > 0 ? BAR_W : dx < 0 ? -1 : k), yy = e.iy + (dy > 0 ? BAR_H : dy < 0 ? -1 : k);
+    if (xx < 0 || yy < 0 || xx >= W || yy >= H) continue;
+    const p = part[yy * W + xx]; if (p < P_TU || p > P_TR || (!dx && TDX[p]) || dx * TDX[p] + dy * TDY[p] < 0) continue;
+    // Vertical screws require the full width; horizontal screws use the nearest two-row lane.
+    const x = (xx & ~3), y = Math.max(yy & ~3, Math.min((yy & ~3) + 2, e.iy));
+    if (entTubeMove(e, x, TDX[p] || dy ? y : e.iy, true)) return true;
+  }
+  return false;
+}
+function entTubeTick(e, p) {
+  e.vx = e.vy = 0; e.x = e.ix; e.y = e.iy;
+  const ci = (e.iy + 1) * W + e.ix + 1;
+  if ((tick & 1) || netSat(ci) <= 0 || rnd() > netSat(ci)) return;
+  const dx = TDX[p], dy = TDY[p];
+  let x = e.ix + dx, y = e.iy + dy, next = 0, ax = 0, ay = 0;
+  for (let k = 0; k < (dx ? BAR_H : BAR_W); k++) {
+    const xx = e.ix + (dx > 0 ? BAR_W : dx < 0 ? -1 : k), yy = e.iy + (dy > 0 ? BAR_H : dy < 0 ? -1 : k);
+    if (xx < 0 || yy < 0 || xx >= W || yy >= H) return;
+    const q = part[yy * W + xx];
+    if (q >= P_TU && q <= P_TR && q !== p) { next = q; ax = xx; ay = yy; break; }
+  }
+  if (next) {
+    if (TDX[next] === -dx && TDY[next] === -dy) return;
+    x = ax & ~3; y = Math.max(ay & ~3, Math.min((ay & ~3) + 2, e.iy));
+    if (entTubeMove(e, x, y, true)) stats.moved++;
+    return;
+  }
+  if (entTubeAt(x, y)) { if (entTubeMove(e, x, y, true)) stats.moved++; return; }
+  // Clear the mouth in one move so the next tick can derive ordinary falling from position.
+  x = e.ix + dx * BAR_W; y = e.iy + dy * BAR_H;
+  if (!entTubeFree(x, y) || entTubeAt(x, y)) return;
+  for (let yy = y; yy < y + BAR_H; yy++) for (let xx = x; xx < x + BAR_W; xx++) if (part[yy * W + xx]) return;
+  if (entTubeMove(e, x, y)) { e.vx = dx ? dx * 0.5 : (rnd() - 0.5) * 0.4; e.vy = dy * 0.6; stats.moved++; }
+}
 function entTick() {
   for (let k = ents.length - 1; k >= 0; k--) {
     const e = ents[k];
     entMark(e, 0);
     entCurM = e.m;
     const ix = e.ix, iy = e.iy;
-    // what is underneath?
-    let belt = 0, bsat = 0, support = iy + BAR_H >= H;
-    if (!support) {
-      const yb = iy + BAR_H;
-      for (let dx = 0; dx < BAR_W; dx++) {
-        const x = ix + dx; if (x < 0 || x >= W) continue;
-        const j = yb * W + x, m = mat[j];
-        if (m === BELTL || m === BELTR) { const s = netSat(j); if (s > bsat) { bsat = s; belt = m === BELTR ? 1 : -1; } }
-        else if (part[j] === P_FILTER && !filterPassAt(e.m, j) && (yb & 3) === 0) { bsat = 1; belt = blockV[(yb >> 2) * BW + (x >> 2)] & 128 ? 1 : -1; }
-        if (entSolidCell(j)) support = true;
+    const tube = entTubeAt(ix, iy);
+    if (tube) entTubeTick(e, tube);
+    else {
+      // what is underneath?
+      let belt = 0, bsat = 0, support = iy + BAR_H >= H;
+      if (!support) {
+        const yb = iy + BAR_H;
+        for (let dx = 0; dx < BAR_W; dx++) {
+          const x = ix + dx; if (x < 0 || x >= W) continue;
+          const j = yb * W + x, m = mat[j];
+          if (m === BELTL || m === BELTR) { const s = netSat(j); if (s > bsat) { bsat = s; belt = m === BELTR ? 1 : -1; } }
+          else if (part[j] === P_FILTER && !filterPassAt(e.m, j) && (yb & 3) === 0) { bsat = 1; belt = blockV[(yb >> 2) * BW + (x >> 2)] & 128 ? 1 : -1; }
+          if (entSolidCell(j)) support = true;
+        }
       }
+      const ci = Math.min(H - 1, iy + 1) * W + Math.min(W - 1, ix + 1);
+      const inLiq = PH[mat[ci]] === PH_LIQUID;
+      if (support) { if (e.vy > 0) e.vy = 0; e.vx = belt ? belt * 0.5 * bsat : e.vx * 0.55; }
+      else { e.vy = Math.min(inLiq ? 0.35 : 1.3, e.vy + 0.07); e.vx *= inLiq ? 0.8 : 0.985; }
+      if (belt && bsat > 0) stats.moved += 0.05;
+      e.x += e.vx; e.y += e.vy;
+      // step toward the new rounded position one cell at a time
+      let tx = Math.round(e.x), ty = Math.round(e.y), cx = ix, cy = iy;
+      while (cx !== tx) { const s = Math.sign(tx - cx); if (entFreeAt(cx + s, cy)) cx += s; else if (belt && entTubeEnter(e, s, 0)) { cx = e.ix; cy = e.iy; e.x = cx; e.y = cy; break; } else { e.vx = 0; e.x = cx; break; } }
+      while (cy !== ty) { const s = Math.sign(ty - cy); if (entTubeAt(cx, cy)) break; if (entFreeAt(cx, cy + s)) cy += s; else if (entTubeEnter(e, 0, s)) { cx = e.ix; cy = e.iy; break; } else { e.vy = 0; e.y = cy; break; } }
+      if (support && !belt && entTubeEnter(e, 0, 1)) { cx = e.ix; cy = e.iy; }
+      if (!entTubeAt(cx, cy) && !entFreeAt(cx, cy)) {
+        // something moved into us (a grain fell in): try to step up out of it
+        let freed = false;
+        for (let u = 1; u < 6; u++) if (entFreeAt(cx, cy - u)) { cy -= u; e.y = cy; freed = true; break; }
+        if (!freed) e.y = cy;
+      }
+      e.ix = cx; e.iy = cy;
     }
-    const ci = Math.min(H - 1, iy + 1) * W + Math.min(W - 1, ix + 1);
-    const inLiq = PH[mat[ci]] === PH_LIQUID;
-    if (support) { if (e.vy > 0) e.vy = 0; e.vx = belt ? belt * 0.5 * bsat : e.vx * 0.55; }
-    else { e.vy = Math.min(inLiq ? 0.35 : 1.3, e.vy + 0.07); e.vx *= inLiq ? 0.8 : 0.985; }
-    if (belt && bsat > 0) stats.moved += 0.05;
-    e.x += e.vx; e.y += e.vy;
-    // step toward the new rounded position one cell at a time
-    let tx = Math.round(e.x), ty = Math.round(e.y), cx = ix, cy = iy;
-    while (cx !== tx) { const s = Math.sign(tx - cx); if (entFreeAt(cx + s, cy)) cx += s; else { e.vx = 0; e.x = cx; break; } }
-    while (cy !== ty) { const s = Math.sign(ty - cy); if (entFreeAt(cx, cy + s)) cy += s; else { e.vy = 0; e.y = cy; break; } }
-    if (!entFreeAt(cx, cy)) {
-      // something moved into us (a grain fell in): try to step up out of it
-      let freed = false;
-      for (let u = 1; u < 6; u++) if (entFreeAt(cx, cy - u)) { cy -= u; e.y = cy; freed = true; break; }
-      if (!freed) e.y = cy;
-    }
-    e.ix = cx; e.iy = cy;
+    const cx = e.ix, cy = e.iy;
     // heat: the bar tends toward the temperature around it
     const T = temp[Math.min(H - 1, cy + 1) * W + Math.min(W - 1, cx + 1)];
     e.T += (T - e.T) * 0.04;

src/sim/machine-tick.js

@@ -113,7 +113,7 @@ function machinesTick() {
     const list = tubeLists[p], dx = TDX[p], dy = TDY[p], dj = dy * W + dx, flat = dy === 0;
     for (let k = 0; k < list.length; k++) {
       const i = list[k];
-      if (part[i] !== p) continue;
+      if (part[i] !== p || occ[i]) continue;
       const m = mat[i];
       if (m === EMPTY || PH[m] !== PH_POWDER) { if (m === EMPTY || PH[m] !== PH_SOLID) tubeIntake(i, p, dx, dy); continue; }
       if (stamp[i] === tickStamp) continue;

src/sim/pieces.js

@@ -42,7 +42,7 @@ const PIECES = [
   { id: 'belt', code: BP_BELT, name: 'Belt', kind: 'block', cost: [[CASH, 12]], dirs: ['left', 'right'],
     desc: 'Carries loose grains and bars resting on top of it, left or right, in a layer up to a block deep. Water and other liquids drain through it.' },
   { id: 'tube', code: BP_TUBE, name: 'Screw tube', kind: 'block', cost: [[CASH, 25]], dirs: ['up', 'right', 'down', 'left'],
-    desc: 'A turning screw that draws in loose material and pushes it along, four grains wide. Water and other liquids run straight through it; the screw never carries them. Stack them pointing up to lift ore out of a mine, and turn the top one sideways to unload. Copper softens around 1000°C.' },
+    desc: 'A turning screw that draws in loose grains and whole bars and pushes them along, four grains wide. Water and other liquids run straight through it; the screw never carries them. Stack them pointing up to lift ore out of a mine, and turn the top one sideways to unload. Copper softens around 1000°C.' },
   { id: 'filter', code: BP_FILTER, name: 'Filter', kind: 'block', cost: [[CASH, 40]], dirs: ['left', 'right'], filter: true,
     desc: 'A stretch of belt with a mesh in it. Put it in a line of belts and it joins them as one belt. Pick materials and a mode: drop them through and carry everything else along, or carry them and drop the rest. Liquids drain through.' },
   { id: 'shaft', code: BP_SHAFT, name: 'Shaft', kind: 'block', cost: [[LWOOD, 8]], hidden: POWER_FREE,

src/ui/notebook.js

@@ -195,6 +195,7 @@ function controlsHtml() {
   3. Build (3) a chamber of stone wall blocks with a one-block vent in the roof, a floor of clay Grates, and an Ingot mold right under the grates. The notebook's Blueprints tab has this as a starter design.<br>
   4. Tick coal and copper ore in your bag and pick Ticked mix (Q/E, or click it at the bottom of the bag). Fly inside (the bot passes through what you build) and right click to blow an even mix onto the grates: about 50 of each. (Ore first and coal on top works too; coal buried under ore will not light.) Light a coal grain on top with the Igniter.<br>
   5. When the ingot sets, bars drop out of the bottom of the mold onto whatever is under it. Leave one open block under it: a belt below that carries them off, or vacuum them up. Leftover metal stays for the next firing. Ingot molds empty themselves: bars, junk and scrap drop below, slag is thrown away and the grate above is raked. Removing any mold returns its set metal to your bag: whole bars as bars, the rest as scrap.<br>
+  Screw tubes carry grains and whole bars: feed bars in from a belt, turn corners and unload at the mouth.<br>
   6. Blow the bars into the trade dock: they sell the moment they drop through its grate, and bars pay far more than ore. Watch the Market page for orders that pay double. Money buys belts, screw tubes and fans; pay down the claim there too.<br>
   7. From there: deeper ores (tin, zinc, silver, gold), alloys, fans for hotter fires, iron and steel.</p>
 `;