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|
module Game.Map
( Map (..),
Object (..),
objects,
load,
render,
isBlocked,
)
where
import Control.Monad
import Data.Maybe (mapMaybe)
import qualified Game.Utils as U
import qualified SDL
import Text.JSON
import Text.JSON.Types
data Tileset = Tileset
{ cols :: Int,
width :: Int,
height :: Int,
firstGid :: Int
}
deriving (Show)
data Layer
= TileLayer
{name :: String, tiles :: [Int]}
| ObjectLayer
{name :: String, objects :: [Object]}
deriving (Show)
-- | The object types in the map.
data Object
= PlayerEntity Int Int
| BatteryEntity Int Int
deriving (Show)
data JsonMapData = JsonMapData
{ width :: Int,
height :: Int,
tileset :: Tileset,
layers :: [Layer]
}
deriving (Show)
instance JSON Tileset where
showJSON = undefined
readJSON (JSArray [JSObject obj]) = do
Tileset
<$> valFromObj "columns" obj
<*> valFromObj "tilewidth" obj
<*> valFromObj "tileheight" obj
<*> valFromObj "firstgid" obj
readJSON _ = mzero
instance JSON Layer where
showJSON = undefined
readJSON (JSObject obj) =
case get_field obj "type" of
Just "tilelayer" ->
TileLayer <$> valFromObj "name" obj <*> valFromObj "data" obj
Just "objectgroup" ->
ObjectLayer <$> valFromObj "name" obj <*> valFromObj "objects" obj
_ -> Error "unsupported layer type"
readJSON _ = mzero
instance JSON Object where
showJSON = undefined
readJSON (JSObject obj) =
case get_field obj "name" of
Just "Player" ->
PlayerEntity <$> valFromObj "x" obj <*> valFromObj "y" obj
Just "Battery" ->
BatteryEntity <$> valFromObj "x" obj <*> valFromObj "y" obj
Just (JSString (JSONString s)) -> Error $ "unsupported entity " ++ show s
e -> Error $ "unsupported entity in " ++ show e
readJSON _ = mzero
instance JSON JsonMapData where
showJSON = undefined
readJSON (JSObject obj) =
JsonMapData
<$> valFromObj "width" obj
<*> valFromObj "height" obj
<*> valFromObj "tilesets" obj
<*> valFromObj "layers" obj
readJSON _ = mzero
data MapData = MapData
{ width :: Int,
height :: Int,
tileset :: Tileset,
tileLayers :: [[Int]],
blocked :: [Int],
objects :: [Object]
}
deriving (Show)
data Map = Map MapData SDL.Texture
-- | Loads a map from a JSON file.
load :: String -> SDL.Texture -> IO Map
load filename tex = do
d <- readFile filename
case decode d :: Result JsonMapData of
Ok s -> do
let tileLayers = mapMaybe (filterTileLayer (\l -> l.name /= "Blocked")) s.layers
blockedLayers = mapMaybe (filterTileLayer (\l -> l.name == "Blocked")) s.layers
blockedLayer <- case blockedLayers of
[l] -> pure l
xs -> error $ "A single \"Blocked\" layer expected, " ++ show (length xs) ++ " found"
pure $
Map
MapData
{ width = s.width,
height = s.height,
tileset = s.tileset,
tileLayers = tileLayers,
blocked = blockedLayer,
objects = concat $ mapMaybe filterObjectLayer s.layers
}
tex
Error e -> error e
where
filterTileLayer :: (Layer -> Bool) -> Layer -> Maybe [Int]
filterTileLayer f l = case l of
TileLayer _ tiles -> if f l then Just tiles else Nothing
_ -> Nothing
filterObjectLayer :: Layer -> Maybe [Object]
filterObjectLayer l = case l of
ObjectLayer _ objs -> Just objs
_ -> Nothing
-- | Check for collision detection vs "Blocked" TileLayer.
-- x and y in pixels.
isBlocked :: Map -> Int -> Int -> Bool
isBlocked (Map (MapData mapWidth _ ts _ blocked _) _) x y =
blocked !! ((x `div` ts.width) + (y `div` ts.height) * mapWidth) >= ts.firstGid
-- | Return the objects in a map.
objects :: Map -> [Object]
objects (Map md _) = md.objects
-- | Renders a map.
render :: SDL.Renderer -> Map -> IO ()
render renderer (Map mapData tex) = do
mapM_
( \layer ->
mapM_
( \(x, y) ->
renderTile x y $ layer !! (x + (y * mapData.width))
)
index
)
mapData.tileLayers
where
index = [(x, y) | x <- [0 .. mapData.width - 1], y <- [0 .. mapData.height - 1]]
columns = mapData.tileset.cols
firstgid = mapData.tileset.firstGid
tileWidth = mapData.tileset.width
tileHeight = mapData.tileset.height
renderTile :: Int -> Int -> Int -> IO ()
renderTile x y tile
| tile < firstgid = pure ()
| otherwise = do
let tx = (tile - firstgid) `rem` columns
ty = (tile - firstgid) `div` columns
src = U.rect (tx * tileWidth) (ty * tileHeight) tileWidth tileHeight
dst = U.rect (x * tileWidth) (y * tileHeight) tileWidth tileHeight
SDL.copy renderer tex (Just src) (Just dst)
|
