{-# LANGUAGE ViewPatterns, LambdaCase #-}
import System.PortAudio
import Control.Applicative
import Control.Concurrent
import Control.Monad
import Foreign.C.String
import Foreign.C.Types
import Foreign hiding (void)
import Linear (V2(..))
import qualified Data.Vector as V
import qualified Data.Vector.Storable.Mutable as MV
import System.Environment
import System.Exit
period :: Int
period = 128
table :: V.Vector Float
table = V.fromList [sin t | i <- [0..period - 1], let t = fromIntegral i / fromIntegral period * 2 * pi]
callback :: MVar Int -> Status -> input -> MV.IOVector (V2 Float) -> IO StreamCallbackResult
callback phase _ _ o = do
i0 <- takeMVar phase
go i0 0
putMVar phase $ i0 + n
return Continue
where
n = MV.length o
go :: Int -> Int -> IO ()
go i0 i
| i == n = return ()
| otherwise = do
let v = table V.! ((i0 + i) `mod` period)
MV.write o i (V2 v v)
go i0 (i + 1)
main :: IO ()
main = getArgs >>= \case
((read -> rate) : (read -> buf) : _) -> withPortAudio $ do
(_, dev : _) <- getDevices
phase <- newMVar 0
let output = streamParameters dev 0
withStream rate buf noConnection output mempty (callback phase)
$ threadDelay $ 1000 * 1000
_ -> usageExit
usageExit :: IO ()
usageExit = do
pname <- getProgName
putStrLn $ "\nUsage: " ++ pname ++ " <sample rate> <buffer size>\n"
exitSuccess