Add (persistent) volume control

src/Dodge/Config/Data.hs

@@ -0,0 +1,39 @@
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE StrictData #-}
+module Dodge.Config.Data (
+      Configuration (..)
+    , defaultConfig
+    , volume_master
+    , volume_sound
+    , volume_music
+    ) where
+
+import Data.Aeson
+import Foreign.C.Types
+import GHC.Generics
+import qualified GHC.Int
+import qualified SDL
+import System.Directory
+import Control.Lens
+
+data Configuration = Configuration
+  { _volume_master   :: Float
+  , _volume_sound    :: Float
+  , _volume_music    :: Float
+  }
+  deriving (Generic, Show)
+
+makeLenses ''Configuration
+
+instance ToJSON Configuration where
+  toEncoding = genericToEncoding defaultOptions
+
+instance FromJSON Configuration
+
+defaultConfig = Configuration
+    { _volume_master = 1
+    , _volume_sound  = 1
+    , _volume_music  = 1
+    }
+ 

src/Dodge/Config/Update.hs

@@ -1,10 +1,10 @@
 {-|
-IO actions that apply config side effects and save it to disk.
+IO actions that apply config side effects and save configuration settings to disk.
 -}
 module Dodge.Config.Update
     where
 import Dodge.Data
-import Dodge.LoadConfig
+import Dodge.Config.Data
 import Sound
 
 import Data.Aeson (encodeFile)
@@ -12,11 +12,14 @@ import Control.Monad (when)
 
 updateDodgeConfig :: World -> IO ()
 updateDodgeConfig w = case _menuLayers w of
-    (ConfigSaveScreen _: _) -> do
-        putStrLn "Saving config"
+    (ConfigSaveScreen : _) -> do
+        putStrLn "Saving config to data/dodge.config.json"
         encodeFile "data/dodge.config.json" cfig
-    _ -> when (_configNeedsUpdate w) $ do
-        setSoundVolume ( _volume_master cfig * _volume_sound cfig)
-        setMusicVolume ( _volume_master cfig * _volume_music cfig)
+    _ -> when (_configNeedsUpdate w) (setVolume cfig)
   where
     cfig = _config w
+
+setVolume :: Configuration -> IO ()
+setVolume cfig = do
+    setSoundVolume ( _volume_master cfig * _volume_sound cfig)
+    setMusicVolume ( _volume_master cfig * _volume_music cfig)