frpsdl.hs

{-# LANGUAGE RankNTypes #-}
import Reactive.Banana
import Reactive.Banana.Frameworks
import qualified Graphics.UI.SDL as SDL
import qualified Graphics.UI.SDL.Image as Image

main = do
  SDL.init [SDL.InitEverything]
  SDL.rawSetCaption (Just "foobar") Nothing
  SDL.setVideoMode 640 480 32 []
  img <- Image.load "foo.png"
  let networkDescription :: forall t. Frameworks t => Moment t ()
      networkDescription = do
        bMouse <- fromPoll $ SDL.getMouseState >>= \(x, y, _) -> return (x, y)
        eMouse <- changes bMouse
        reactimate $ fmap (render img) eMouse
  network <- compile networkDescription
  actuate network
  loop
  where
    loop = do
      event <- SDL.pollEvent
      case event of
        SDL.Quit -> return ()
        _ -> loop

render :: SDL.Surface -> (Int, Int) -> IO ()
render img (x, y) = do
  surf <- SDL.getVideoSurface
  SDL.blitSurface img (Just (SDL.Rect (x-25) (y-25) 50 50)) surf Nothing
  return ()

foo.png: http://imgur.com/2fawij8