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{-# LANGUAGE CPP #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE MultiWayIf #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE PatternSynonyms #-}
module Lazyfoo.Lesson13 (main) where
import Control.Monad
import Data.Monoid
import Data.Word
import Foreign.C.Types
import SDL.Vect
import SDL (($=))
import qualified SDL
import Paths_sdl2 (getDataFileName)
#if !MIN_VERSION_base(4,8,0)
import Data.Foldable
#endif
screenWidth, screenHeight :: CInt
(screenWidth, screenHeight) = (640, 480)
data Texture = Texture SDL.Texture (V2 CInt)
loadTexture :: SDL.Renderer -> FilePath -> IO Texture
loadTexture r filePath = do
surface <- getDataFileName filePath >>= SDL.loadBMP
size <- SDL.surfaceDimensions surface
let key = V4 0 maxBound maxBound maxBound
SDL.surfaceColorKey surface $= Just key
t <- SDL.createTextureFromSurface r surface
SDL.freeSurface surface
return (Texture t size)
renderTexture :: SDL.Renderer -> Texture -> Point V2 CInt -> Maybe (SDL.Rectangle CInt) -> IO ()
renderTexture r (Texture t size) xy clip =
let dstSize = maybe size (\(SDL.Rectangle _ size') -> size') clip
in SDL.copy r t clip (Just (SDL.Rectangle xy dstSize))
setTextureAlpha :: Texture -> Word8 -> IO ()
setTextureAlpha (Texture t _) rgb = SDL.textureAlphaMod t $= rgb
setTextureBlendMode :: Texture -> SDL.BlendMode -> IO ()
setTextureBlendMode (Texture t _) bm = SDL.textureBlendMode t $= bm
main :: IO ()
main = do
SDL.initialize [SDL.InitVideo]
SDL.HintRenderScaleQuality $= SDL.ScaleLinear
do renderQuality <- SDL.get SDL.HintRenderScaleQuality
when (renderQuality /= SDL.ScaleLinear) $
putStrLn "Warning: Linear texture filtering not enabled!"
window <-
SDL.createWindow
"SDL Tutorial"
SDL.defaultWindow {SDL.windowInitialSize = V2 screenWidth screenHeight}
SDL.showWindow window
renderer <-
SDL.createRenderer
window
(-1)
SDL.RendererConfig
{ SDL.rendererType = SDL.UnacceleratedRenderer
, SDL.rendererTargetTexture = False
}
SDL.rendererDrawColor renderer $= V4 maxBound maxBound maxBound maxBound
modulatedTexture <- loadTexture renderer "examples/lazyfoo/fadeout.bmp"
setTextureBlendMode modulatedTexture SDL.BlendAlphaBlend
backgroundTexture <- loadTexture renderer "examples/lazyfoo/fadein.bmp"
let loop alpha = do
events <- SDL.pollEvents
let (Any quit, Sum alphaAdjustment) =
foldMap (\case
SDL.QuitEvent -> (Any True, mempty)
SDL.KeyboardEvent e ->
(\x -> (mempty, x)) $
if | SDL.keyboardEventKeyMotion e == SDL.Pressed ->
case SDL.keysymScancode (SDL.keyboardEventKeysym e) of
SDL.ScancodeW -> Sum 32
SDL.ScancodeS -> Sum (-32)
_ -> mempty
| otherwise -> mempty
_ -> mempty) $
map SDL.eventPayload events
SDL.rendererDrawColor renderer $= V4 maxBound maxBound maxBound maxBound
SDL.clear renderer
renderTexture renderer backgroundTexture 0 Nothing
let alpha' = max 0 (min 255 (alpha + alphaAdjustment))
setTextureAlpha modulatedTexture (fromIntegral alpha')
renderTexture renderer modulatedTexture 0 Nothing
SDL.present renderer
unless quit (loop alpha')
loop (255 :: Int) -- We use 'Int' to avoid integer overflow
SDL.destroyRenderer renderer
SDL.destroyWindow window
SDL.quit
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