DouKaku?

module Main where

import System
import Graphics.UI.GLUT
import System.Random

display n = do
    clear [ ColorBuffer ]
    color $ Color3 (0.6::Double) 0.6 0.6
    preservingMatrix $ do
        renderPrimitive Polygon $ mapM_ vertex (nlist n)
    flush
    where
        nlist n = nVertex n du
        du = 2.0 * pi / fromIntegral n

nVertex n du
    | n == 0        = [ point ]
    | otherwise     = point : nVertex (n-1) du
    where
        radius = 0.75
        x = toRational (radius * cos (pi / 2.0 + fromIntegral n * du))
        y = toRational (radius * sin (pi / 2.0 + fromIntegral n * du))
        point = Vertex3 (fromRational x) (fromRational y) (0.0 :: GLfloat)


timer n = do
        rotate (1::Double) (Vector3 0 1 0)
        display n
        finish
        addTimerCallback 10 (timer n)

inputKey (Char 'q') _ _ _  = exitWith ExitSuccess
inputKey _ _ _ _            = return ()

main = do
    (fileName, args) <- getArgsAndInitialize
    let n = case args of
        [] -> 3
        _ -> max 3 $ read $ head args
    createWindow "Haskell OpenGL"
    displayCallback $= display n
    addTimerCallback 1000 (timer n)
    keyboardMouseCallback $= Just (inputKey)
    mainLoop