feat: threads

app/level.ts

@@ -39,6 +39,13 @@ export type Chunk = {
   rock: Mesh
   /** Flowers (color-atlas texture); drawn double-sided, so kept separate. */
   flowers: Mesh
+  /** Cheap low-poly impostors of the same trees/boulders, drawn instead of the
+   *  full meshes once the chunk is past `config.lodDistance` (renderScene). Same
+   *  textures as bark/leaf/needle/rock. Bushes/flowers have no far version. */
+  barkFar: Mesh
+  leafFar: Mesh
+  needleFar: Mesh
+  rockFar: Mesh
 }
 
 /** The playground: a flat-floored room dropped into the center of a big open
@@ -215,17 +222,26 @@ function buildChunks(trees: Tree[], boulders: Boulder[], bushes: Bush[], flowers
       const needle = mesh()
       const rock = mesh()
       const flowerMesh = mesh()
+      const barkFar = mesh()
+      const leafFar = mesh()
+      const needleFar = mesh()
+      const rockFar = mesh()
       Terrain.patch(TERRAIN, grass, x0, z0, x1, z1, TERRAIN_SUBDIV, TERRAIN_SUBDIV, GROUND_UV)
       for (const tree of trees) {
         if (inCell(tree.position, x0, z0, x1, z1)) {
-          Tree.build(tree, bark, tree.kind === "oak" ? leaf : needle)
+          const foliage = tree.kind === "oak" ? leaf : needle
+          const foliageFar = tree.kind === "oak" ? leafFar : needleFar
+          Tree.build(tree, bark, foliage)
+          Tree.build(tree, barkFar, foliageFar, "impostor")
         }
       }
       for (const boulder of boulders) {
         if (inCell(boulder.position, x0, z0, x1, z1)) {
           Boulder.build(boulder, rock)
+          Boulder.build(boulder, rockFar, "impostor")
         }
       }
+      // Bushes share the near leaf mesh; they just drop out past lodDistance.
       for (const bush of bushes) {
         if (inCell(bush.position, x0, z0, x1, z1)) {
           Bush.build(bush, leaf)
@@ -240,7 +256,7 @@ function buildChunks(trees: Tree[], boulders: Boulder[], bushes: Bush[], flowers
       if (b === null) {
         continue
       }
-      chunks.push({ ...b, grass, bark, leaf, needle, rock, flowers: flowerMesh })
+      chunks.push({ ...b, grass, bark, leaf, needle, rock, flowers: flowerMesh, barkFar, leafFar, needleFar, rockFar })
     }
   }
   return chunks