-module Sim ( ChunkData, initSimSpace, defaultChunkData ) where
+module Sim ( initSimSpace, testSim, physStep, updateWaterChunk, validDirects ) where
+import Debug.Trace
+import Data.Vector ((!), (//))
import qualified Data.Vector as V
-data ChunkData = ChunkData
- { velocity :: (Float, Float)
- , density :: Float
+data Simulation = Simulation
+ { simSpace :: V.Vector ChunkData
+ , simW :: Int
+ , simH :: Int
} deriving (Show)
-defaultChunkData = ChunkData
- { velocity = (0,0)
- , density = 0
+data ChunkType = Air
+ | Water
+ | Wall deriving (Show, Enum)
+
+data ChunkData = ChunkData
+ { chunkType :: ChunkType
+ } deriving (Show)
+
+-- vec accessors
+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
+ { simSpace = V.replicate (y*x) ChunkData { chunkType=Air }
+ , simW = x
+ , simH = y
}
-initSimSpace :: Int -> Int -> V.Vector ChunkData
-initSimSpace x y = V.replicate (y*x) defaultChunkData
+testSim = simSet (initSimSpace 3 3) (ChunkData Water) 1 1
+
+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
+ 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-x,b-y) | a <- [x-1..x+1], b <- [y-1..y+1], not (a==x && b==y)]
--- gaussSeidel
