not loading already loaded chunks

src/game/world/mod.rs

@@ -57,8 +57,12 @@ impl World {
     *   Sends chunk position to the ChunkLoader
     */
     pub fn load_chunk(&mut self, pos: Vector3<i32>) {
-        self.loader.load(pos);
-        self.busy += 1;
+        if let Some(chunk) = self.chunks.get_mut(&pos) {
+            chunk.dirty = true;
+        } else {
+            self.loader.load(pos);
+            self.busy += 1;
+        }
     }
 
     /*