Screw tubes use all their lanes: grains spread sideways inside a tube

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

src/sim/conveyors.js

@@ -91,6 +91,18 @@ function filterRun(b) {
 
 // A cell a grain can be pushed into: empty, or liquid or gas that simply trades places with it
 function roomFor(j) { const t = mat[j]; return t === EMPTY || PH[t] === PH_GAS || PH[t] === PH_LIQUID; }
+// Cross one tube block, far lanes first; corners retain their liquid/gas swaps.
+function tubeSpread(c, x, y, sx, sy, intake = false) {
+  const p = part[c], bx = x >> 2, by = y >> 2;
+  for (;;) {
+    const nx = x + sx, ny = y + sy;
+    if (nx < 0 || ny < 0 || nx >= W || ny >= H || (nx >> 2) !== bx || (ny >> 2) !== by) break;
+    const j = ny * W + nx;
+    if (part[j] !== p || occ[j] || (intake ? mat[j] !== EMPTY || stamp[j] === tickStamp : !roomFor(j))) break;
+    move(c, j, x, y, nx, ny); c = j; x = nx; y = ny;
+  }
+  return c;
+}
 // 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) {
@@ -109,6 +121,7 @@ function tubeIntake(i, p, dx, dy) {
     if (pj >= P_TU && pj <= P_TR) continue; // other tube cells move their own contents
     if (pj === P_GRATE || pj === P_FILTER) continue;
     move(j, i, nx, ny, x, y);
+    if (ox !== -dx || oy !== -dy) tubeSpread(i, x, y, -ox, -oy, true);
     return;
   }
 }