Cleanup preload, add basic frame time checking

src/Loop.hs

@@ -47,43 +47,60 @@ setupLoop
             destroyWindow 
             $ \window -> bracket 
                 (glCreateContext window) 
-                (\con -> GL.finish >> glDeleteContext con)
-                $ \_ -> bracket 
+                ( \con -> GL.finish >> glDeleteContext con)
+                $ \_   -> bracket 
                     initParams 
                     paramCleanup 
-                    $ \setup -> doLoop setup window startWorld sideEffects eventFn worldFn
+                    $ doLoop window startWorld sideEffects eventFn worldFn
 
 doLoop 
-    :: params 
-    -> Window 
+    :: Window 
     -> world
     -> (params -> world -> IO params) 
     -> (world -> Event -> Maybe world) 
     -> (world -> Maybe world) 
+    -> params 
     -> IO ()
 doLoop 
-    setup 
     window 
     startWorld
     worldSideEffects 
     eventFn 
     worldUpdate 
+    startParams 
   = do
-    startLoopTicks <- ticks
-    newParams <- worldSideEffects setup startWorld
+    startTicks <- ticks
+    newParams <- worldSideEffects startParams startWorld
     glSwapWindow window
     events <- pollEvents
     maybeUpdatedWorld <- foldM (applyEventIO eventFn) (Just startWorld) events
     case maybeUpdatedWorld >>= worldUpdate of
         Just updatedWorld -> do 
             performGC
-            endLoopTicks <- ticks -- it might be better to use System.Clock (monotonic)
-            let delay = max 0 (20 + fromIntegral startLoopTicks - fromIntegral endLoopTicks)
+            endTicks <- ticks -- it might be better to use System.Clock (monotonic)
+
+            let delay = max 0 (20 + fromIntegral startTicks - fromIntegral endTicks)
             threadDelay (delay * 1000 )
-            endTime <- ticks
-            doLoop newParams window updatedWorld worldSideEffects eventFn worldUpdate
+
+            doLoop window updatedWorld worldSideEffects eventFn worldUpdate newParams
         Nothing -> return ()
 
+applyEventsIO 
+    :: (world -> Event -> Maybe world)
+    -> world
+    -> [Event]
+    -> IO (Maybe world)
+applyEventsIO fn w es = foldM (applyEventIO fn) (Just w) es
+
+--eventCloseOrResize :: Event -> IO (Maybe Event)
+--eventCloseOrResize e = case eventPayload e of
+--    QuitEvent           -> return Nothing
+--    WindowClosedEvent _ -> return Nothing
+--    WindowSizeChangedEvent (WindowSizeChangedEventData {windowSizeChangedEventSize = V2 x y})
+--                        -> GL.viewport $= (GL.Position 0 0,GL.Size x y) >> return (Just e)
+--    _                   -> return $ Just e
+--
+
 applyEventIO :: (world -> Event -> Maybe world) -> Maybe world -> Event -> IO (Maybe world)
 applyEventIO fn mw e = case eventPayload e of
     QuitEvent           -> return Nothing