diff --git a/main/Scene.cc b/main/Scene.cc
index 58c2d69..b19cdf6 100644
--- a/main/Scene.cc
+++ b/main/Scene.cc
@@ -186,8 +186,9 @@ void Scene::taskLoop()
         int task_id = m_distrib.getTask();
         if (task_id < 0)
             break;
-        int i = task_id / m_width;
-        int j = task_id % m_width;
+        int pixel = task_id * UNIT_TASK_SIZE;
+        int i = pixel / m_width;
+        int j = pixel % m_width;
         for (int t = 0; t < UNIT_TASK_SIZE; t++)
         {
             renderPixel(j, i, &data[3 * t]);