Rafael Cunha de Almeida <almeida...@gmail.com> writes:
> My main function goes like this:
> (...)
> rotX <- newIORef (0.0::GLfloat)
> rotY <- newIORef (0.0::GLfloat)
> pos <- newIORef (0.0::GLfloat, 0.0, 0.0)
>
> displayCallback $= display (map f range) rotX rotY pos
>
> keyboardMouseCallback $= Just (keyboardMouse rotX rotY pos)
> (...)
>
> ...
>
> In a state-based language I would place display and keyboardMouse in one
> module and let them communcate to each other like they want. In haskell,
> I'm not quite sure how to do it except by that parameter passing style.
You could try something like this: (and apologies in advance for any
typoes)
------------------------------------------------------------------------
import Control.Concurrent.MVar
data MyState = MyState {
rotX :: GLFloat
, rotY :: GLFloat
, pos :: (GLFloat,GLFloat)
}
myDisplayCallback :: MVar MyState -> IO ()
myDisplayCallback =
flip modifyMVar_ $ \(MyState rx ry p) -> do
(newRx, newRy, newP) <- yourCodeGoesHere
return $ MyState newRx newRy newP
main = do
mvar <- newMVar $ MyState 0 0 (0,0)
displayCallback $= myDisplayCallback mvar
...
------------------------------------------------------------------------
Cheers,
G.
--
Gregory Collins <g...@gregorycollins.net>
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