New-world lakes start level; no trees in water (t96)

src/sim/worldgen.js

@@ -190,12 +190,14 @@ function* worldSteps(seedIn, w, h) {
   }
   yield [0.72, 'Snow and trees'];
   // trees
+  const trees = [];
   for (let x = 12; x < w - 12;) {
     const sy = surfY[x];
     const ok = mat[sy * w + x] === GRASS && mat[sy * w + x + 1] === GRASS && !noTree[x] && Math.abs(x - spawnX) > 6 && !(x > spawnX + 14 && x < spawnX + 72); // none where the dock goes
     if (ok && rng() < 0.7) {
+      const tree = { x, y: sy - 1, cells: [] }; trees.push(tree);
       const th = 9 + Math.floor(rng() * 8);
-      const setW = (xx, yy) => { if (xx < 0 || yy < 1 || xx >= w) return; const i = yy * w + xx; if (mat[i] === EMPTY) bgm[i] = WOOD; };
+      const setW = (xx, yy) => { if (xx < 0 || yy < 1 || xx >= w) return; const i = yy * w + xx; if (mat[i] === EMPTY) { bgm[i] = WOOD; tree.cells.push(i, WOOD); } };
       for (let k = 1; k <= th; k++) for (let dx = 0; dx < 2; dx++) setW(x + dx, sy - k);
       // two branches
       for (const side of [-1, 1]) { const by = sy - th + 3 + Math.floor(rng() * 3); for (let k = 1; k <= 3; k++) setW(x + (side < 0 ? -k : 1 + k), by - (k >> 1)); }
@@ -206,7 +208,7 @@ function* worldSteps(seedIn, w, h) {
         for (let yy = Math.floor(cy - r); yy <= cy + r; yy++) for (let xx = Math.floor(cx - r); xx <= cx + r; xx++) {
           if (xx < 0 || yy < 1 || xx >= w) continue;
           const ex = (xx - cx) / r, ey = (yy - cy) / (r * 0.85);
-          if (ex * ex + ey * ey <= 1 && hash2(xx, yy, worldSeed + 7) % 9 !== 0) { const i = yy * w + xx; if (mat[i] === EMPTY && !bgm[i]) bgm[i] = LEAVES; }
+          if (ex * ex + ey * ey <= 1 && hash2(xx, yy, worldSeed + 7) % 9 !== 0) { const i = yy * w + xx; if (mat[i] === EMPTY && !bgm[i]) { bgm[i] = LEAVES; tree.cells.push(i, LEAVES); } }
         }
       }
       x += 16 + Math.floor(rng() * 20);
@@ -258,9 +260,24 @@ function* worldSteps(seedIn, w, h) {
   // re-ambient after settling, then start clean
   for (let i = 0; i < N; i++) { const m = mat[i]; if (m !== MAGMA) temp[i] = AMB[(i / w) | 0]; life[i] = PH[m] === PH_LIQUID && FRZ[m] ? 255 : 0; }
   tick = 0;
+  // Settling can carry lakes past noTree; leave their connected low banks treeless too.
+  bgm.fill(0);
+  for (const tree of trees) {
+    let wet = false;
+    for (let root = tree.x; root <= tree.x + 1 && !wet; root++) for (const d of [-1, 1]) {
+      for (let x = root; x >= 0 && x < w; x += d) {
+        const m = mat[tree.y * w + x];
+        if (m === WATER) { wet = true; break; }
+        if (m !== EMPTY && PH[m] !== PH_GAS) break;
+      }
+    }
+    if (!wet) for (let k = 0; k < tree.cells.length; k += 2) bgm[tree.cells[k]] = tree.cells[k + 1];
+  }
   findTreeBases();
   placeDock(spawnX + 34);
   hot.fill(0); awake.fill(0); updateRoof();
+  // Keep the generated grains intact, but let unfinished lakes level from the first tick.
+  for (let i = 0; i < N; i++) if (mat[i] === WATER) wakeIdx(i);
   resetEconomy(); resetWeather();
   weather.base = worldWater();
   bot.x = spawnX - 2; bot.y = surfY[spawnX] - 14; bot.vx = 0; bot.vy = 0;