Mixer.hs

module Mixer (
	initMixer,
	playSE,
	playBGM,
	stopBGM
) where

import Graphics.UI.SDL.Mixer
import Data.IORef (IORef, newIORef, readIORef, writeIORef)
import System.IO.Unsafe (unsafePerformIO)

freq, channel, samples :: Int
format :: AudioFormat

freq = 22050
format = AudioS16Sys
channel = 2
samples = 4096

initMixer :: IO ()
initMixer = do
	openAudio freq format channel samples

playSE :: Maybe Chunk -> IO ()
playSE Nothing = return ()
playSE (Just ad) = flip catch (\_ -> return ()) $ do
	playChannel (-1) ad 0
	return ()

playingBGM :: IORef (Maybe Music)
playingBGM = unsafePerformIO $ newIORef Nothing

stopBGM :: IO ()
stopBGM = do
	m <- readIORef playingBGM
	case m of
		Nothing -> return ()
		Just mus -> do
			freeMusic mus
			writeIORef playingBGM Nothing

playBGM :: String -> IO ()
playBGM bgmfn = do
	stopBGM
	maybeMusic <- tryLoadMUS bgmfn
	case maybeMusic of
		Just music -> do
			playMusic music (-1)
			writeIORef playingBGM $ Just music
		Nothing -> return ()