Boxxle in Haskell + SDL
Haskell || Die
The main driver for me studying programming in the first place was because I love programming video games. After the discovery of SDL bindings for Haskell, along with an amazing tutorial, I couldn't resist trying to make a simple game in Haskell. It took a lottttttt of reading and time in GHCI before I could start making any real progress, but after a couple days I began to wrap my head around things. This is a small remake of the GameBoy game Boxxle, a very simple but fun puzzle game.
The full code (with 40 levels) can be found on my GitHub
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Below is the current version. I am still wrapping my head around the intricacies of Haskell, so feel free to make suggestions :)
Boxxle.hs
{-# LANGUAGE FlexibleContexts #-} -- http://stackoverflow.com/questions/10865963/using-the-state-monad-to-hide-explicit-state
-- @author Kenny Cason
-- kennycason.com 2013
import Graphics.UI.SDL
import Graphics.UI.SDL.TTF as TTFG
import Graphics.UI.SDL.Mixer
import Data.List
import Control.Monad
import Control.Monad.State
import Control.Monad.Reader
import Timer
-- game data
-- levels from: http://www.gamefaqs.com/gameboy/585643-boxxle/faqs/52416
rooms = [
roomBuilder
[[1,1,1,1,1,0,0,0,0] -- map tiles
,[1,0,0,0,1,0,0,0,0]
,[1,0,0,0,1,0,1,1,1]
,[1,0,0,0,1,0,1,4,1]
,[1,1,1,0,1,1,1,4,1]
,[0,1,1,0,0,0,0,4,1]
,[0,1,0,0,0,1,0,0,1]
,[0,1,0,0,0,1,1,1,1]
,[0,1,1,1,1,1,0,0,0]
]
[(Coord 2 2), (Coord 3 2), (Coord 2 3)] -- boxes
[(Coord 7 3), (Coord 7 4), (Coord 7 5)] -- targets
(Coord 1 1) -- start pos
,roomBuilder
[[1,1,1,1,1,1,1,1,1,1]
,[1,4,4,0,0,0,0,0,0,1]
,[1,4,4,0,0,0,1,0,0,1]
,[1,0,0,1,0,1,1,0,1,1]
,[1,0,0,0,0,0,0,0,1,0]
,[1,1,1,1,1,0,1,0,1,0]
,[0,0,1,0,0,0,0,0,1,0]
,[0,0,1,0,0,0,0,0,1,0]
,[0,0,1,1,1,1,1,1,1,0]
]
[(Coord 3 2), (Coord 4 3), (Coord 2 4), (Coord 4 6)]
[(Coord 1 1), (Coord 2 1), (Coord 1 2), (Coord 2 2)]
(Coord 1 1)
,roomBuilder
[[0,1,1,1,1,0]
,[1,1,0,0,1,0]
,[1,0,0,0,1,0]
,[1,1,0,0,1,1]
,[1,1,0,0,0,1]
,[1,4,0,0,0,1]
,[1,4,4,0,4,1]
,[1,1,1,1,1,1]
]
[(Coord 2 2), (Coord 2 3), (Coord 3 4), (Coord 2 5)]
[(Coord 1 5), (Coord 1 6), (Coord 2 6), (Coord 4 6)]
(Coord 1 2)
,roomBuilder
[[0,1,1,1,1,1,0,0]
,[0,1,0,0,1,1,1,0]
,[0,1,0,0,0,0,1,0]
,[1,1,1,0,1,0,1,1]
,[1,4,1,0,1,0,0,1]
,[1,4,0,0,0,1,0,1]
,[1,4,0,0,0,0,0,1]
,[1,1,1,1,1,1,1,1]
]
[(Coord 3 2), (Coord 2 5), (Coord 5 6)]
[(Coord 1 4), (Coord 1 5), (Coord 1 6)]
(Coord 2 1)
,roomBuilder
[[0,1,1,1,1,1,1,1,0,0]
,[0,1,0,0,0,0,0,1,1,1]
,[1,1,0,1,1,1,0,0,0,1]
,[1,0,0,0,0,0,0,0,0,1]
,[1,0,4,4,1,0,0,0,1,1]
,[1,1,4,4,1,0,0,0,1,0]
,[0,1,1,1,1,1,1,1,1,0]
]
[(Coord 2 2), (Coord 4 3), (Coord 6 3), (Coord 5 4)]
[(Coord 2 4), (Coord 3 4), (Coord 2 5), (Coord 3 5)]
(Coord 2 1)
]
roomBuilder ::[[Int]] -> [Coord] -> [Coord] -> Coord -> Room
roomBuilder tiles boxes targets startPos = Room {
tiles = tiles
,walls = foldTiles tiles
,boxes = boxes
,targets = targets
,startPos = startPos
}
-- global constants
startLevel = 1
tEmpty = 0
tBrick = 1
tBox = 2
tPlayer = 3
tTarget = 4
textColor = Color 0x33 0x33 0x33
-- type defines
data Direction = UP | DOWN | LEFT | RIGHT deriving (Eq, Enum)
data Move = Move {
dir :: Direction
,dx :: Int
,dy :: Int
}
data Coord = Coord {
x :: Int
,y :: Int
} deriving (Eq)
data Room = Room {
tiles :: [[Int]]
,walls :: [Coord]
,boxes :: [Coord]
,targets :: [Coord]
,startPos :: Coord
}
data GameData = GameData {
timer :: Timer
,room :: Room
,player :: Coord
,level :: Int
}
data GameConfig = GameConfig {
screen :: Surface
,sprites :: Surface
,front :: Font
,music :: Music
}
type GameState = StateT GameData IO
type GameEnv = ReaderT GameConfig GameState
-- monad state get/put/modify
getGameData :: MonadState GameData m => m GameData
getGameData = get
putGameData :: MonadState GameData m => GameData -> m ()
putGameData = put
modifyGameData :: MonadState GameData m => (GameData -> GameData) -> m ()
modifyGameData = modify
getPlayer :: MonadState GameData m => m Coord
getPlayer = gets player
getRoom :: MonadState GameData m => m Room
getRoom = gets room
getLevel :: MonadState GameData m => m Int
getLevel = gets level
getTimer :: MonadState GameData m => m Timer
getTimer = gets timer
putTimer :: MonadState GameData m => Timer -> m ()
putTimer t = modify $ \s -> s { timer = t }
modifyTimerM :: MonadState GameData m => (Timer -> m Timer) -> m ()
modifyTimerM act = getTimer >>= act >>= putTimer
getScreen :: MonadReader GameConfig m => m Surface
getScreen = liftM screen ask
getSprites :: MonadReader GameConfig m => m Surface
getSprites = liftM sprites ask
getFont :: MonadReader GameConfig m => m Font
getFont = liftM front ask
-- main functions
newGame :: Int -> IO (GameConfig, GameData)
newGame lvl = do
-- setVideoMode 320 288 32 []
setVideoMode 448 352 32 []
setCaption "Boxxle - Haskell" []
screen <- getVideoSurface
sprites <- loadBMP "img/boxxle.bmp"
font <- openFont "fonts/steelpla.ttf" 18
timer <- start defaultTimer
openAudio 22050 AudioS16Sys 2 4096
music <- loadMUS "music/main.wav"
playMusic music (-1)
return (GameConfig screen sprites font music, GameData timer room (startPos room) lvl)
where room = (rooms !! (lvl - 1))
levelUp :: GameData -> GameData
levelUp gd = gd { level = newLevel, room = nextRoom, player = (startPos nextRoom) }
where
newLevel = (level gd) + 1
nextRoom = rooms !! ((level gd) `mod` (length rooms))
resetLevel :: GameData -> GameData
resetLevel gd = gd { room = resetRoom, player = (startPos resetRoom) }
where resetRoom = rooms !! ( ((level gd) - 1) `mod` (length rooms) )
handleWin :: GameData -> GameData
handleWin gd| isWin = levelUp gd
| otherwise = gd
where isWin = length (intersect
(boxes currentRoom)
(targets currentRoom)) == length (targets currentRoom)
where currentRoom = (room gd)
foldTiles :: [[Int]] -> [Coord]
foldTiles tiles =
[Coord x y -- generate a Coord pair
| (y, row) <- enumerate tiles -- for each row with its coordinate
, (x, tile) <- enumerate row -- for each tile in the row (with coordinate)
, tile == 1] -- if the tile is 1
where enumerate = zip [0..]
getSpriteSheetOffset :: Int -> Maybe Rect
getSpriteSheetOffset n = Just (Rect offx offy 32 32)
where
offx = n * 32
offy = 0
applySurface :: Int -> Int -> Surface -> Surface -> Maybe Rect -> IO Bool
applySurface x y src dst clip = blitSurface src clip dst offset
where offset = Just Rect { rectX = x, rectY = y, rectW = 0, rectH = 0 }
drawSprite :: Surface -> Surface -> Int -> Int -> Int -> IO Bool
drawSprite screen sprites n x y = blitSurface
sprites (getSpriteSheetOffset n)
screen dst
where dst = Just (Rect x y 32 32)
drawPlayer :: Surface -> Surface -> Int -> Int -> IO Bool
drawPlayer screen sprites x y = blitSurface sprites src screen dst
where
src = (getSpriteSheetOffset tPlayer)
dst = Just (Rect (x * 32) (y * 32) 32 32)
drawTile :: Surface -> Surface -> Int -> [Coord] -> IO()
drawTile screen sprites tile coords = mapM_ (\c -> drawSprite screen sprites tile ((x c) * 32) ((y c) * 32) ) coords
drawBricks :: Surface -> Surface -> [Coord] -> IO()
drawBricks screen sprites bricks = drawTile screen sprites tBrick bricks
drawBoxes :: Surface -> Surface -> [Coord] -> IO()
drawBoxes screen sprites boxes = drawTile screen sprites tBox boxes
drawTargets :: Surface -> Surface -> [Coord] -> IO()
drawTargets screen sprites targets = drawTile screen sprites tTarget targets
collide :: Coord -> Coord -> Bool
collide c1 c2 = ((x c1) == (x c2)) && ((y c1) == (y c2))
offsetCoord :: Coord -> Move -> Coord
offsetCoord c move = c { x = (x c) + (dx move), y = (y c) + (dy move) }
collideWithWorld :: Coord -> Room -> Bool
collideWithWorld c room = (foldr (||) False (map (collide c) (walls room)))
collideWithBoxes :: Coord -> Room -> Bool
collideWithBoxes c room = (foldr (||) False (map (collide c) (boxes room)))
canBoxMove :: Coord -> Room -> Bool
canBoxMove box room = not ((collideWithWorld box room) || (collideWithBoxes box room))
movePlayer :: Move -> GameData -> GameData
movePlayer move gd | collideWithWorld newPlayerPos (room gd) = gd
| otherwise = gd { player = Coord { x = (x playerPos) + (dx move), y = (y playerPos) + (dy move)} }
where
playerPos = (player gd)
newPlayerPos = (offsetCoord playerPos move)
moveBox :: Move -> Coord -> Coord
moveBox move box = box { x = (x box) + (dx move), y = (y box) + (dy move) }
checkBox :: Room -> Coord -> Move -> Coord -> Coord
checkBox room playerPos move box| collidedWithPlayer && (dir move) == UP && boxCanMove = moveBox move box
| collidedWithPlayer && (dir move) == DOWN && boxCanMove = moveBox move box
| collidedWithPlayer && (dir move) == LEFT && boxCanMove = moveBox move box
| collidedWithPlayer && (dir move) == RIGHT && boxCanMove = moveBox move box
| otherwise = box
where
collidedWithPlayer = collide playerPos box -- player collided
boxCanMove = canBoxMove newBoxPos room
where newBoxPos = offsetCoord box move
checkBoxes :: Room -> Coord -> Move -> [Coord] -> [Coord]
checkBoxes room playerPos move boxes = map (checkBox room playerPos move) boxes
handleBoxes :: Move -> GameData -> GameData
handleBoxes move gd = gd { room = (room gd) { boxes = (checkBoxes (room gd) playerPos move (boxes (room gd)) ) } }
where playerPos = offsetCoord (player gd) move
-- if the resulting move yields the player standing on a box, undo it
undoPlayer :: Move -> GameData -> GameData
undoPlayer move gd | collideWithBoxes playerPos (room gd) = gd { player = Coord { x = (x playerPos) - (dx move), y = (y playerPos) - (dy move)} }
| otherwise = gd
where
playerPos = (player gd)
handleKeyboard :: Event -> GameData -> GameData
handleKeyboard (KeyDown (Keysym SDLK_UP _ _)) gd = ((handleWin.undoPlayer move).(movePlayer move).(handleBoxes move)) gd
where move = Move { dir = UP, dx = 0, dy = -1 }
handleKeyboard (KeyDown (Keysym SDLK_DOWN _ _)) gd = ((handleWin.undoPlayer move).(movePlayer move).(handleBoxes move)) gd
where move = Move { dir = DOWN, dx = 0, dy = 1 }
handleKeyboard (KeyDown (Keysym SDLK_LEFT _ _)) gd = ((handleWin.undoPlayer move).(movePlayer move).(handleBoxes move)) gd
where move = Move { dir = LEFT, dx = -1, dy = 0 }
handleKeyboard (KeyDown (Keysym SDLK_RIGHT _ _)) gd = ((handleWin.undoPlayer move).(movePlayer move).(handleBoxes move)) gd
where move = Move { dir = RIGHT, dx = 1, dy = 0 }
handleKeyboard (KeyDown (Keysym SDLK_r _ _)) gd = resetLevel gd
handleKeyboard (KeyDown (Keysym SDLK_s _ _)) gd = levelUp gd
handleKeyboard _ d = d
loop :: GameEnv ()
loop = do
timer <- getTimer
screen <- getScreen
sprites <- getSprites
pos <- getPlayer
room <- getRoom
font <- getFont
level <- getLevel
message <- liftIO $ renderTextSolid font ("level " ++ (show level)) textColor
modifyTimerM $ liftIO . start
quit <- whileEvents $ modifyGameData . handleKeyboard
liftIO $ do
bgRect <- Just `liftM` getClipRect screen
white <- mapRGB' screen 0xff 0xff 0xff
fillRect screen bgRect white
drawBricks screen sprites (walls room)
drawTargets screen sprites (targets room)
drawBoxes screen sprites (boxes room)
drawPlayer screen sprites (x pos) (y pos)
applySurface 340 3 message screen Nothing
Graphics.UI.SDL.flip screen
ticks <- getTimerTicks timer
when (ticks < secsPerFrame) $ do
delay $ secsPerFrame - ticks
unless quit loop
where
framesPerSecond = 30
secsPerFrame = 1000 `div` framesPerSecond
mapRGB' = mapRGB . surfaceGetPixelFormat
whileEvents :: MonadIO m => (Event -> m ()) -> m Bool
whileEvents act = do
event <- liftIO pollEvent
case event of
Quit -> return True
NoEvent -> return False
_ -> do
act event
whileEvents act
runLoop :: GameConfig -> GameData -> IO ()
runLoop = evalStateT . runReaderT loop
main = withInit [InitEverything] $ do -- withInit calls quit
result <- TTFG.init
if not result
then putStr "Failed to init ttf\n"
else do
(gc, gd) <- newGame startLevel
runLoop gc gd
haltMusic
closeAudio
TTFG.quit
Arrived
Ninja Turdle