-----------------------------------------------------------------------------
-- |
-- Module      :  Graphics.Rendering.OGL.Monad
-- Copyright   :  (c) Neal Alexander 2008
-- License     :  BSD-style (see the file libraries/OpenGL/LICENSE)
-- 
-- Maintainer  :  relapse.dev@gmx.com
-- Stability   :  experimental
-- Portability :  ghc
-- 
-- GL Contexts:
-- 
-- - 'MonadGL' a command that can be used in any OpenGL context.
-- 
-- - 'GL' a basic command that cannot be used between begin\/end.
-- 
-- - 'PrimitiveGL' a primitive command sent during begin\/end context.
-- 

module Graphics.Rendering.OGL.Monad (liftIO, liftGL, runGL, runGLA, GL(..), runPrimitive, PrimitiveGL(..), MonadGL) where 

import Control.Monad
import Control.Applicative
import Control.Monad.Trans
import Control.Arrow

class MonadIO m => MonadGL m

instance MonadGL GL
instance MonadGL PrimitiveGL

newtype GL a = GL (IO a) deriving (Functor, Monad, MonadIO)
newtype PrimitiveGL a = PrimitiveGL (IO a) deriving (Functor, Monad, MonadIO)



runGL :: GL a -> IO a
runGL (GL x) = x

-- | arrow version of runGL
runGLA :: Kleisli GL a a -> Kleisli IO a a
runGLA a = Kleisli $ runGL . runKleisli a



-- | Same as: liftIO . runGL
liftGL :: MonadIO m => GL a -> m a
liftGL = liftIO . runGL


-- | This is used internally and shouldnt be needed by the user.
runPrimitive :: PrimitiveGL a -> IO a
runPrimitive (PrimitiveGL x) = x