a little optimization

src/Affection/Particle.hs

@@ -117,21 +117,25 @@ updateParticleSystem
   -> Affection us ParticleSystem
 updateParticleSystem sys sec upd draw = do
   x <- catMaybes <$> mapM (updateParticle sec upd) (partStorList $ partSysParts sys)
+  -- liftIO $ traceIO $ show $ length x
   -- x <- catMaybes <$> foldM (updateParticle sec upd) [] (reverse $ psParts sys)
-  when (not $ null x) $ do
-    -- liftIO $ G.gegl_node_link_many $ map particleStackCont (partStorList $ partSysParts sys)
-    -- liftIO $ traceIO "linking last node to output"
-    liftIO $ G.gegl_node_link (particleStackCont $ head x) (partSysNode sys)
-  mapM_ (draw (partSysBuffer sys) (partSysNode sys)) x
-  return $ sys
-    { partSysParts = (partSysParts sys)
-      { partStorList = x
-      , partStorLatest =
-          if null x
-          then Nothing
-          else partStorLatest (partSysParts sys)
-      }
-    }
+  if (not $ null x)
+    then do
+      -- liftIO $ G.gegl_node_link_many $ map particleStackCont (partStorList $ partSysParts sys)
+      -- liftIO $ traceIO "linking last node to output"
+      liftIO $ G.gegl_node_link (particleStackCont $ head x) (partSysNode sys)
+      mapM_ (draw (partSysBuffer sys) (partSysNode sys)) x
+      return $ sys
+        { partSysParts = (partSysParts sys)
+          { partStorList = x
+          , partStorLatest =
+              if null x
+              then Nothing
+              else partStorLatest (partSysParts sys)
+          }
+        }
+    else
+      return sys
 
 -- | Function for inserting a new 'Particle' into its 'PartileSystem'
 insertParticle