diff --git a/world.js b/world.js
index 5cae85c..4ec2777 100644
--- a/world.js
+++ b/world.js
@@ -114,23 +114,20 @@ export function blockLookup(world, x, y, z) {
     };
 }
 
-function makeChunkBuffer(gl, data, z0, x0, lookup) {
-    const sideNeighbors = (bi, i, j, k) => {
-        if (i === 0 || j === 0 || i === 15 || j === 15) {
-            return [
-                { block: lookup(i - 1, j, k), dir: '-z', faceCenter: [x0 + j, k, z0 + i - 0.5] },
-                { block: lookup(i + 1, j, k), dir: '+z', faceCenter: [x0 + j, k, z0 + i + 0.5] },
-                { block: lookup(i, j - 1, k), dir: '-x', faceCenter: [x0 + j - 0.5, k, z0 + i] },
-                { block: lookup(i, j + 1, k), dir: '+x', faceCenter: [x0 + j + 0.5, k, z0 + i] },
-            ];
+function makeChunkBuffer(gl, data, z0, x0, blockLookup) {
+    const lookup = (i, j, k) => {
+        if (i < 0 || j < 0 || i > 15 || j > 15) {
+            return blockLookup(i, j, k);
         }
-        return [
-            { block: data[bi - 256 * 16], dir: '-z', faceCenter: [x0 + j, k, z0 + i - 0.5] },
-            { block: data[bi + 256 * 16], dir: '+z', faceCenter: [x0 + j, k, z0 + i + 0.5] },
-            { block: data[bi - 256], dir: '-x', faceCenter: [x0 + j - 0.5, k, z0 + i] },
-            { block: data[bi + 256], dir: '+x', faceCenter: [x0 + j + 0.5, k, z0 + i] },
-        ];
+        return data[256*(16*i + j) + k];
     };
+    const sideNeighbors = (i, j, k) =>
+        [
+            { block: lookup(i - 1, j, k), dir: '-z', faceCenter: [x0 + j, k, z0 + i - 0.5] },
+            { block: lookup(i + 1, j, k), dir: '+z', faceCenter: [x0 + j, k, z0 + i + 0.5] },
+            { block: lookup(i, j - 1, k), dir: '-x', faceCenter: [x0 + j - 0.5, k, z0 + i] },
+            { block: lookup(i, j + 1, k), dir: '+x', faceCenter: [x0 + j + 0.5, k, z0 + i] },
+        ];
 
     const faces = [];
 
@@ -159,7 +156,7 @@ function makeChunkBuffer(gl, data, z0, x0, lookup) {
                     }
                 })();
 
-                for (let {block, dir, faceCenter} of sideNeighbors(bi, i, j, k)) {
+                for (let {block, dir, faceCenter} of sideNeighbors(i, j, k)) {
                     if (block === BlockType.AIR) {
                         faces.push(makeFace(dir, sideTexture, faceCenter));
                     }