diff --git a/index.js b/index.js
index feff417..1067a69 100644
--- a/index.js
+++ b/index.js
@@ -377,8 +377,6 @@ async function main() {
         return;
     }
 
-    const worldGl = await initWorldGl(gl);
-
     const params = {
         projMatrix: se3.perspective(Math.PI / 3, canvas.clientWidth / canvas.clientHeight, 0.1, 100.0),
         camera: {
@@ -392,7 +390,7 @@ async function main() {
         flying: false,
         isOnGround: false,
         world: makeWorld(),
-        worldGl,
+        worldGl: await initWorldGl(gl),
     }
 
     document.querySelector('#lightx').oninput = e => {
diff --git a/world.js b/world.js
index 4ec2777..9bc25f2 100644
--- a/world.js
+++ b/world.js
@@ -98,7 +98,7 @@ export function blockLookup(world, x, y, z) {
     if (chunk === undefined) {
         return {
             type: BlockType.STONE,
-            x, y, z,
+            centerPosition: [x, y, z],
         };
     }
 
@@ -108,9 +108,11 @@ export function blockLookup(world, x, y, z) {
 
     return {
         type: chunk.data[256 * (16*i + j) + k],
-        x: j,
-        y: k,
-        z: i,
+        centerPosition: [
+            Math.floor(midx),
+            k,
+            Math.floor(midz),
+        ],
     };
 }