Fix docs and make GlossEnv available to users

rhine-gloss/src/FRP/Rhine/Gloss/IO.hs

@@ -8,12 +8,14 @@
 
 -- | Wrapper to write @gloss@ applications in Rhine, using concurrency.
 module FRP.Rhine.Gloss.IO (
-  GlossConcT,
+  GlossEnv (..),
+  GlossConcT (..),
   paintIO,
   clearIO,
   paintAllIO,
   GlossEventClockIO (..),
   GlossSimClockIO (..),
+  makeGlossEnv,
   launchInGlossThread,
   launchGlossThread,
   flowGlossIO,
@@ -119,21 +121,22 @@ instance GetClockProxy GlossSimClockIO
 
 -- * Reactimation
 
-{- | Apply this to supply the 'GlossConcT' effect.
-   Creates a new thread in which @gloss@ is run,
-   and feeds the clocks 'GlossEventClockIO' and 'GlossSimClockIO'.
+-- | Create the concurrent variables to communicate with the @gloss@ backend.
+makeGlossEnv ::
+  (MonadIO m) =>
+  m GlossEnv
+makeGlossEnv = liftIO $ GlossEnv <$> newEmptyMVar <*> newEmptyMVar <*> newIORef Blank <*> newIORef 0
 
-   Usually, this function is applied to the result of 'flow',
-   so you can handle all occurring effects as needed.
-   If you only use @gloss@ in your whole signal network,
-   you can use 'flowGlossIO' instead.
+{- | Helper function for 'launchInGlossThread'.
+
+Creates concurrent variables and launches the @gloss@ backend in a separate thread.
 -}
 launchGlossThread ::
   (MonadIO m) =>
   GlossSettings ->
   m GlossEnv
 launchGlossThread GlossSettings {..} = do
-  vars <- liftIO $ GlossEnv <$> newEmptyMVar <*> newEmptyMVar <*> newIORef Blank <*> newIORef 0
+  vars <- makeGlossEnv
   let
     getPic GlossEnv {picRef} = readIORef picRef
     -- Only try to put so this doesn't hang in case noone is listening for events or ticks