Audio.hs

   1 module Audio where
   2
   3 import Prelude hiding (lookup)
   4 import Graphics.UI.SDL.Mixer
   5 import Data.IntMap
   6 import Control.Monad
   7
   8
   9 data Audio = Audio {
  10   sounds :: IntMap Chunk
  11 }
  12
  13 maxChan = 32
  14
  15 startAudio :: IO Audio
  16 startAudio = do
  17   openAudio defaultFrequency AudioS16LSB 2 2048
  18   allocateChannels maxChan
  19   --load sound files
  20   --setup music streams
  21   return Audio { sounds = empty }
  22
  23 endAudio :: IO ()
  24 endAudio = do
  25   closeAudio
  26
  27 whenJust :: (Monad m) => Maybe a -> (a -> m b) -> m ()
  28 whenJust Nothing _ = return ()
  29 whenJust (Just x) f = f x >> return ()
  30
  31 playSound :: Int -> Audio -> IO ()
  32 playSound id audio = do
  33   let chunk = lookup id (sounds audio)
  34   whenJust chunk (\x -> tryPlayChannel (-1) x 0)
  35   return ()
  36
  37 fadeAll :: Audio -> IO ()
  38 fadeAll audio = do
  39   fadeOutChannel (-1) 200
  40   return ()
  41