-module Sim ( initSimSpace, testSim, physStep, validDirects ) where
+module Sim (
+ Simulation, simSpace,
+ ChunkType, ChunkData, chunkType,
+ initSimSpace, testSim, physStep, updateWaterChunk, validDirects, simToString
+) where
+import Debug.Trace
import Data.Vector ((!), (//))
import qualified Data.Vector as V
--- Simulation simSpace simW simH
-data Simulation = Simulation (V.Vector ChunkData) Int Int deriving (Show)
+data Simulation = Simulation
+ { simSpace :: V.Vector ChunkData
+ , simW :: Int
+ , simH :: Int
+ } deriving (Show)
-data ChunkType = Empty
+data ChunkType = Air
| Water
- | Wall deriving (Show)
+ | Wall deriving (Show, Enum)
-data ChunkData = ChunkData ChunkType deriving (Show)
+data ChunkData = ChunkData
+ { chunkType :: ChunkType
+ } deriving (Show)
-- vec accessors
-simGet (Simulation s w _) x y = s ! (y*w+x)
-simSet (Simulation s w h) c x y = Simulation (s // [(y*w+x,c)]) w h
+simGet Simulation{simSpace=s,simW=w} x y = s ! (y*w+x)
+simSet sim@Simulation{simSpace=s,simW=w,simH=h} c x y = sim { simSpace = (s // [(y*w+x,c)]) }
+simGetChunkType sim x y = chunkType $ simGet sim x y
-initSimSpace x y = Simulation (V.replicate (y*x) (ChunkData Empty)) x y
+initSimSpace x y = Simulation
+ { simSpace = V.replicate (y*x) ChunkData { chunkType=Air }
+ , simW = x
+ , simH = y
+ }
-testSim = simSet (initSimSpace 10 10) (ChunkData Water) 5 0
+testSim = simSet (initSimSpace 3 3) (ChunkData Water) 1 1
-physStep sim@(Simulation _ w h) = _physStep [(x, y) | x <- [0..w-1], y <- [0..h-1]] (initSimSpace w h) sim
-_physStep grid acc sim@(Simulation s w h) =
+physStep sim@Simulation{simW=w,simH=h} = _physStep [(x, y) | x <- [0..w-1], y <- [0..h-1]] sim sim
+-- _physStep grid acc sim@Simulation{simSpace=s,simW=w,simH=h} | trace ("" ++ show acc) False = undefined
+_physStep grid acc sim@Simulation{simSpace=s,simW=w,simH=h} =
if null grid then acc
else _physStep (tail grid) next sim
where x = fst $ head grid
y = snd $ head grid
- next = sim
+ valid = validDirects x y w h
+ next = case simGetChunkType sim x y of
+ Water -> updateWaterChunk x y valid acc
+ _ -> acc
+
+-- takes in list of valid chunks, as well as the sim to modify
+updateWaterChunk x y valid sim =
+ -- if the chunk below is free, fall straight down
+ if elem (0,-1) valid && fromEnum (simGetChunkType sim x (y-1)) == fromEnum Air
+ then
+ let moved = simSet sim ChunkData { chunkType=Air } x y
+ in simSet moved ChunkData { chunkType=Water } x (y-1)
+ else if elem (-1,-1) valid && fromEnum (simGetChunkType sim (x-1) (y-1)) == fromEnum Air
+ then
+ let moved = simSet sim ChunkData { chunkType=Air } x y
+ in simSet moved ChunkData { chunkType=Water } (x-1) (y-1)
+ else if elem (1,-1) valid && fromEnum (simGetChunkType sim (x+1) (y-1)) == fromEnum Air
+ then
+ let moved = simSet sim ChunkData { chunkType=Air } x y
+ in simSet moved ChunkData { chunkType=Water } (x+1) (y-1)
+ -- stay put
+ else sim
-- gets chunks around a given chunk that are inside grid
validDirects x y w h = filter
(\q -> 0 <= (fst q) && (fst q) < w && (snd q) <= 0 && (snd q) < h)
- [(a,b) | a <- [x-1..x+1], b <- [y-1..y+1], not (a==x && b==y)]
+ [(a-x,b-y) | a <- [x-1..x+1], b <- [y-1..y+1], not (a==x && b==y)]
+
+simToString :: Simulation -> [Char]
+simToString sim@Simulation{simW=w} =
+ let simStr = V.toList $ V.map chunkToChar $ simSpace sim
+ in insert w '\n' simStr
+
+-- from https://stackoverflow.com/questions/12659562/insert-specific-element-y-after-every-n-elements-in-a-list
+insert :: Int -> a -> [a] -> [a]
+insert n y xs = countdown n xs where
+ countdown 0 xs = y:countdown n xs
+ countdown _ [] = []
+ countdown m (x:xs) = x:countdown (m-1) xs
+chunkToChar :: ChunkData -> Char
+chunkToChar c =
+ case chunkType c of
+ Water -> '~'
+ Air -> '.'
+ _ -> '?'
