diff --git a/src/main/c/fluidsim.c b/src/main/c/fluidsim.c
index e55a536..a472e33 100644
--- a/src/main/c/fluidsim.c
+++ b/src/main/c/fluidsim.c
@@ -677,16 +677,17 @@ JNIEXPORT void JNICALL Java_electrosphere_FluidSim_simulate(
     //add density
     {
         for(int i = 0; i < numChunks; i++){
-            chunkJRaw = getChunk(i);
-            chunkMask = (*env)->GetIntField(env,chunkJRaw,chunkmaskJId);
-            d = getBuffArr(dJId);
-            d0 = getBuffArr(d0JId);
-            u = getBuffArr(uJId);
-            v = getBuffArr(vJId);
-            w = getBuffArr(wJId);
-            u0 = getBuffArr(u0JId);
-            v0 = getBuffArr(v0JId);
-            w0 = getBuffArr(w0JId);
+            Chunk * currentChunk = chunks[i];
+            chunkJRaw = currentChunk->jchunk;
+            chunkMask = currentChunk->chunkMask;
+            d = currentChunk->jd;
+            d0 = currentChunk->jd0;
+            u = currentChunk->ju;
+            v = currentChunk->jv;
+            w = currentChunk->jw;
+            u0 = currentChunk->ju0;
+            v0 = currentChunk->jv0;
+            w0 = currentChunk->jw0;
             Java_electrosphere_FluidSim_addDensity(env,chunkJRaw,DIM,chunkMask,d,d0,timestep);
         }
     }