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Haskell port of F# http://fssnip.net/si
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{-| | |
Haskell port of F# http://fssnip.net/si | |
-} | |
import Control.Applicative ((<$>), (<*>)) | |
import System.Random (randomIO, randomRIO) | |
import qualified Data.ByteString.Lazy as B | |
import Data.Word8 | |
data Expr = | |
VariableX | |
| VariableY | |
| Constant | |
| Sum Expr Expr | |
| Product Expr Expr | |
| Mod Expr Expr | |
| Well Expr | |
| Tent Expr | |
| Sin Expr | |
| Level Expr Expr Expr | |
| Mix Expr Expr Expr | |
deriving Show | |
data Rgb a = Rgb a a a | |
instance (Show a) => Show (Rgb a) where | |
show (Rgb r g b) = "Rgb (" ++ show r ++ "," ++ show g ++ "," ++ show b ++ ")" | |
instance Functor Rgb where | |
fmap f (Rgb r g b) = Rgb (f r) (f g) (f b) | |
type Point = (Double, Double) | |
-- http://goo.gl/yFsQqL | |
mod' :: RealFrac a => a -> a -> a | |
mod' a 0 = a | |
mod' a b = | |
let k = floor $ a / b | |
in a - (fromInteger k) * b | |
next :: IO Double | |
next = randomIO :: IO Double | |
nextInt :: Int -> IO Int | |
nextInt max = randomRIO (0, max) :: IO Int | |
average :: Rgb Double -> Rgb Double -> Double -> Rgb Double | |
average (Rgb r g b) (Rgb r' g' b') w = | |
Rgb (go r r') (go g g') (go r r') | |
where go c c' = w * c + (1.0 - w) * c' | |
well :: Double -> Double | |
well x = 1.0 - 2.0 / (1.0 + x * x) ** 8.0 | |
tent :: Double -> Double | |
tent x = 1.0 - 2.0 * abs x | |
eval :: Expr -> IO (Point -> Rgb Double) | |
eval VariableX = return $ \(x,y) -> Rgb x x x | |
eval VariableY = return $ \(x,y) -> Rgb y y y | |
eval Constant = do | |
(r,g,b) <- (,,) <$> next <*> next <*> next | |
return $ \(x,y) -> Rgb r g b | |
eval (Sum e e') = do | |
(f,f') <- (,) <$> eval e <*> eval e' | |
return $ \(x,y) -> average (f(x,y)) (f'(x,y)) 0.5 | |
eval (Product e e') = do | |
(f,f') <- (,) <$> eval e <*> eval e' | |
return $ \(x,y) -> let Rgb r g b = f(x,y) | |
Rgb r' g' b' = f'(x,y) | |
in Rgb (r * r') (g * g') (b * b') | |
eval (Mod e e') = do | |
(f,f') <- (,) <$> eval e <*> eval e' | |
return $ \(x, y) -> let Rgb r g b = f(x,y) | |
Rgb r' g' b' = f'(x,y) | |
in Rgb (r `mod'` r') (g `mod'` g') (b `mod'` b') | |
eval (Well e) = do | |
f <- eval e | |
return $ \(x, y) -> fmap (well) (f(x,y)) | |
eval (Tent e) = do | |
f <- eval e | |
return $ \(x, y) -> fmap (tent) (f(x,y)) | |
eval (Sin e) = do | |
(phase',freq',f) <- (,,) <$> next <*> next <*> eval e | |
return $ \(x, y) -> let Rgb r g b = f(x,y) | |
phase = phase' * pi | |
freq = (freq' * 5.0) + 1.0 | |
in Rgb (sin (phase + r * freq)) (sin (phase + g * freq)) (sin (phase + b * freq)) | |
eval (Level e e' e'') = do | |
(f,f',f'',threshold') <- (,,,) <$> eval e <*> eval e' <*> eval e'' <*> next | |
return $ \(x, y) -> let Rgb r g b = f(x,y) | |
Rgb r' g' b' = f'(x,y) | |
Rgb r'' g'' b'' = f''(x,y) | |
threshold = (threshold' * 2.0) - 1.0 | |
r_ = if r < threshold then r' else r'' | |
g_ = if g < threshold then g' else g'' | |
b_ = if b < threshold then b' else b'' | |
in Rgb r_ g_ b_ | |
eval (Mix e e' e'') = do | |
(f,f',f'') <- (,,) <$> eval e <*> eval e' <*> eval e'' | |
return $ \(x, y) -> let Rgb n _ _ = f(x,y) | |
w = 0.5 * (n + 1.0) | |
c = f'(x,y) | |
c' = f''(x,y) | |
in average c c' w | |
gen :: Int -> IO Expr | |
gen k = do | |
next' <- next | |
if k <= 0 || next' < 0.01 | |
then do | |
let terminals = [VariableX, VariableY, Constant] | |
index' <- nextInt ((length terminals) - 1) | |
return (terminals !! index') | |
else do | |
let n = \() -> nextInt k | |
let operators = [ \() -> do | |
(n',n'') <- (,) <$> n() <*> n() | |
(e,e') <- (,) <$> gen n' <*> gen n'' | |
return $ Sum e e' | |
, \() -> do | |
(n',n'') <- (,) <$> n() <*> n() | |
(e,e') <- (,) <$> gen n' <*> gen n'' | |
return $ Product e e' | |
, \() -> do | |
(n',n'') <- (,) <$> n() <*> n() | |
(e,e') <- (,) <$> gen n' <*> gen n'' | |
return $ Mod e e' | |
, \() -> do | |
n' <- n() | |
e <- gen n' | |
return $ Well e | |
, \() -> do | |
n' <- n() | |
e <- gen n' | |
return $ Tent e | |
, \() -> do | |
n' <- n() | |
e <- gen n' | |
return $ Sin e | |
, \() -> do | |
(n',n'',m) <- (,,) <$> n() <*> n() <*> n() | |
(e,e',e'') <- (,,) <$> gen n' <*> gen n'' <*> gen m | |
return $ Level e e' e'' | |
, \() -> do | |
(n',n'',m) <- (,,) <$> n() <*> n() <*> n() | |
(e,e',e'') <- (,,) <$> gen n' <*> gen n'' <*> gen m | |
return $ Mix e e' e'' | |
] | |
index' <- nextInt ((length operators) - 1) | |
(operators !! index') () | |
tga :: (Point -> Rgb Double) -> Int -> Int -> String -> IO () | |
tga f width height path = do | |
B.writeFile path (B.pack contents') | |
where | |
pxs = [((adjust x width),(adjust y height)) | y <- [0..height-1], x <- [0..width-1]] | |
pxs' = fmap f pxs | |
adjust p dim = (((toDouble p) + 0.5) - (toDouble dim) / 2) / (toDouble dim) | |
header = | |
[0,0,2,0,0,0,0,0,0,0,0,0, | |
width `mod` 256, truncate (toDouble width / 256), | |
height `mod` 256, truncate (toDouble height / 256), | |
24,0] | |
contents = header ++ (concat $ fmap (\(Rgb r g b) -> asByte b : asByte g : [asByte r]) pxs') | |
contents' = fmap toWord8 contents | |
asByte x = min 255 (max 0 (truncate (128.0 * (x + 1.0)))) | |
toWord8 x = (fromIntegral x) :: Word8 | |
toDouble x = (fromIntegral x) :: Double | |
save :: Int -> IO () | |
save n = do | |
e <- gen 50 | |
f <- eval e | |
tga f 512 384 ("/Users/giacomo/temp/random/Random" ++ show n ++ ".tga") | |
loop :: Int -> (Int -> IO ()) -> IO () | |
loop n f = loop' n f 0 | |
where loop' 0 f _ = return $ () | |
loop' n f acc = do | |
let n' = acc + 1 | |
_ <- f n' | |
loop' (n - 1) f n' | |
main :: IO () | |
main = do | |
loop 1000 save | |
putStrLn "done." |
Thanks to SO guys for help with mod'
: http://stackoverflow.com/questions/32724534/find-the-origin-of-ratio-has-zero-denominator-exception/32725021#32725021.
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