42 lines
1.2 KiB
Haskell
42 lines
1.2 KiB
Haskell
import System.Random (randomRIO)
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type Point = (Float, Float)
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transformation1 :: Point -> Point
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transformation1 (_, y) = (0, 0.16 * y)
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transformation2 :: Point -> Point
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transformation2 (x, y) = (0.85 * x + 0.04 * y, -0.04 * x + 0.85 * y + 1.6)
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transformation3 :: Point -> Point
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transformation3 (x, y) = (0.2 * x - 0.26 * y, 0.23 * x + 0.22 * y + 1.6)
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transformation4 :: Point -> Point
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transformation4 (x, y) = (-0.15 * x + 0.28 * y, 0.26 * x + 0.24 * y + 0.44)
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applyTransformation :: Point -> Float -> Point
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applyTransformation point random
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| random < 0.01 = transformation1 point
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| random < 0.86 = transformation2 point
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| random < 0.93 = transformation3 point
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| otherwise = transformation4 point
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genNextPoint :: Point -> IO Point
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genNextPoint point = do
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random <- randomRIO (0.0, 1.0 :: Float)
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return $ applyTransformation point random
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barnsleyFern :: Point -> Int -> IO [Point]
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barnsleyFern _ 0 = return []
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barnsleyFern startPoint n = do
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x' <- genNextPoint startPoint
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xs <- barnsleyFern x' (n - 1)
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return (startPoint : xs)
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main :: IO ()
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main = do
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putStrLn "Укажите количество шагов рекурсии:"
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input <- getLine
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let n = read input :: Int
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fractal <- barnsleyFern (0, 0) n
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print fractal |