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{-
Torus.hs (adapted from torus.c which is (c) Silicon Graphics, Inc.)
Copyright (c) Sven Panne 2002-2006 <sven.panne@aedion.de>
This file is part of HOpenGL and distributed under a BSD-style license
See the file libraries/GLUT/LICENSE
This program demonstrates the creation of a display list.
-}
import Data.Char ( toLower )
import Data.IORef ( IORef, newIORef )
import System.Exit ( exitWith, ExitCode(ExitSuccess) )
import Graphics.UI.GLUT
data State = State { spinX, spinY :: IORef GLfloat }
makeState :: IO State
makeState = do
x <- newIORef 0
y <- newIORef 0
return $ State { spinX = x, spinY = y }
torus :: Int -> Int -> IO ()
torus numC numT = do
let stepC = 2 * pi / fromIntegral numC :: GLfloat
stepT = 2 * pi / fromIntegral numT
flip mapM_ [ 0 .. numC - 1 ] $ \i ->
renderPrimitive QuadStrip $
flip mapM_ [ 0 .. numT ] $ \j ->
flip mapM_ [ 1, 0 ] $ \k -> do
let s = (fromIntegral ((i + k) `mod` numC) + 0.5) * stepC
t = (fromIntegral ( j `mod` numT) ) * stepT
x = (1 + 0.1 * cos s) * cos t
y = (1 + 0.1 * cos s) * sin t
z = 0.1 * sin s
vertex (Vertex3 x y z)
myInit :: IO DisplayList
myInit = do
theTorus <- defineNewList Compile $
torus 8 25
shadeModel $= Flat
clearColor $= Color4 0 0 0 0
return theTorus
display :: State -> DisplayList -> DisplayCallback
display state theTorus = do
clear [ ColorBuffer ]
loadIdentity
lookAt (Vertex3 0 0 10) (Vertex3 0 0 0) (Vector3 0 1 0)
x <- get (spinX state)
rotate x (Vector3 1 0 0)
y <- get (spinY state)
rotate y (Vector3 0 1 0)
color (Color3 1 1 (1 :: GLfloat))
callList theTorus
flush
reshape :: ReshapeCallback
reshape size@(Size w h) = do
viewport $= (Position 0 0, size)
matrixMode $= Projection
loadIdentity
perspective 30 (fromIntegral w / fromIntegral h) 1 100
matrixMode $= Modelview 0
incSpin :: IORef GLfloat -> IO ()
incSpin spinRef = do
let wrap n s = if s > n then s - n else s
spinRef $~ (wrap 360 . (+ 30))
postRedisplay Nothing
keyboard :: State -> KeyboardMouseCallback
keyboard state (Char c) Down _ _ = case toLower c of
'x' -> incSpin (spinX state)
'y' -> incSpin (spinY state)
'i' -> do spinX state $= 0; spinY state $= 0; postRedisplay Nothing
'\27' -> exitWith ExitSuccess
_ -> return ()
keyboard _ _ _ _ _ = return ()
main :: IO ()
main = do
(progName, _args) <- getArgsAndInitialize
initialDisplayMode $= [ SingleBuffered, RGBMode ]
initialWindowSize $= Size 200 200
createWindow progName
state <- makeState
theTorus <- myInit
reshapeCallback $= Just reshape
keyboardMouseCallback $= Just (keyboard state)
displayCallback $= display state theTorus
mainLoop
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