 
   vec4 finalColor = vec4(0, 0, 0, 0);
 
-  for (uint a = 1; a < maxage; a++)  // all fragments
-  // for (uint a = 1; a <= maxage; a++)  // all fragments
-  {
-
+  for (uint age = 1; age < maxage; age++)  // all fragments
+  {
     vec4 fragmentColor = vec4(0.0f, 0.0f, 0.0f, 0.0f);
-    if (a == 1)
-    {
-      current_fragment_read_status = fetchFragment(ij, a, current_fragment);
+    if (age == 1)
+    {
+      current_fragment_read_status = fetchFragment(ij, age, current_fragment);
       segment_startpos_eye = current_fragment.eyePos.xyz;
     }
     else

    }

    // break; // just the first fragment
  }

  if (maxage == 1)
  {

    activeobjectcount = bitCount(activeobjects);

    // fetch next Fragment
    next_fragment_read_status = fetchFragment(ij, age + 1, next_fragment);
    if (next_fragment_read_status)
    {
      endpos_eye = next_fragment.eyePos.xyz;
