<pre><code>
   9 initGL :: IO ()
 10 initGL = do
 11             shadeModel $= Smooth
 12             clearColor $= Color4 0 180 255 0
 13             clearDepth $= 1
 14             depthFunc $= Just Lequal
 15             hint PerspectiveCorrection $= Nicest
 16
 17 drawFrame :: WindowRefreshCallback
 18 drawFrame = return ()
 19
 20 keyPressed :: KeyCallback
 21 keyPressed _ _ = return ()
 22
 23 close :: WindowCloseCallback
 24 close = return True
 25
 26 targetFPS :: Int
 27 targetFPS = 60
 28
 29 main :: IO ()
 30 main = do
 31           True <- initialize
 32           True <- openWindow $ defaultDisplayOptions
 33                                   { displayOptions_width = 800
 34                                   , displayOptions_height = 600
 35                                   , displayOptions_displayMode = Window
 36                                   , displayOptions_windowIsResizable = False
 37                                   }
 38           setWindowTitle "Eria"
 39           setWindowRefreshCallback drawFrame
 40           setKeyCallback keyPressed
 41           setWindowCloseCallback close
 42
 43           initGL
 44
 45           forever $ do drawFrame
 46                        swapBuffers
 47                        threadDelay $ 1000000 `div` targetFPS
</code></pre>