/usr/share/doc/libghc-glut-doc/examples/RedBook4/BezMesh.hs is in libghc-glut-doc 2.7.0.1-3build1.
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BezMesh.hs (adapted from bezmesh.c which is (c) Silicon Graphics, Inc)
Copyright (c) Sven Panne 2002-2005 <svenpanne@gmail.com>
This file is part of HOpenGL and distributed under a BSD-style license
See the file libraries/GLUT/LICENSE
This program renders a lighted, filled Bezier surface, using two-dimensional
evaluators.
-}
import System.Exit ( exitWith, ExitCode(ExitSuccess) )
import Data.List ( transpose )
import Graphics.UI.GLUT
ctrlPoints :: [[Vertex3 GLfloat]]
ctrlPoints = [
[ Vertex3 (-1.5) (-1.5) 4.0, Vertex3 (-0.5) (-1.5) 2.0,
Vertex3 0.5 (-1.5) (-1.0), Vertex3 1.5 (-1.5) 2.0 ],
[ Vertex3 (-1.5) (-0.5) 1.0, Vertex3 (-0.5) (-0.5) 3.0,
Vertex3 0.5 (-0.5) 0.0, Vertex3 1.5 (-0.5) (-1.0) ],
[ Vertex3 (-1.5) 0.5 4.0, Vertex3 (-0.5) 0.5 0.0,
Vertex3 0.5 0.5 3.0, Vertex3 1.5 0.5 4.0 ],
[ Vertex3 (-1.5) 1.5 (-2.0), Vertex3 (-0.5) 1.5 (-2.0),
Vertex3 0.5 1.5 0.0, Vertex3 1.5 1.5 (-1.0) ]]
initlights :: IO ()
initlights = do
lighting $= Enabled
light (Light 0) $= Enabled
ambient (Light 0) $= Color4 0.2 0.2 0.2 1.0
position (Light 0) $= Vertex4 0 0 2 1
materialDiffuse Front $= Color4 0.6 0.6 0.6 1.0
materialSpecular Front $= Color4 1.0 1.0 1.0 1.0
materialShininess Front $= 50
display :: DisplayCallback
display = do
clear [ ColorBuffer, DepthBuffer ]
preservingMatrix $ do
rotate (85 :: GLfloat) (Vector3 1 1 1)
evalMesh2 Fill (0, 20) (0, 20)
flush
myInit :: IO ()
myInit = do
clearColor $= Color4 0 0 0 0
depthFunc $= Just Less
m <- newMap2 (0, 1) (0, 1) (transpose ctrlPoints)
map2 $= Just (m :: GLmap2 Vertex3 GLfloat)
autoNormal $= Enabled
mapGrid2 $= ((20, (0, 1)), (20, (0, 1 :: GLfloat)))
initlights -- for lighted version only
reshape :: ReshapeCallback
reshape size@(Size w h) = do
viewport $= (Position 0 0, size)
matrixMode $= Projection
loadIdentity
let wf = fromIntegral w
hf = fromIntegral h
if w <= h
then ortho (-4.0) 4.0 (-4.0*hf/wf) (4.0*hf/wf) (-4.0) 4.0
else ortho (-4.0*wf/hf) (4.0*wf/hf) (-4.0) 4.0 (-4.0) 4.0
matrixMode $= Modelview 0
loadIdentity
keyboard :: KeyboardMouseCallback
keyboard (Char '\27') Down _ _ = exitWith ExitSuccess
keyboard _ _ _ _ = return ()
main :: IO ()
main = do
(progName, _args) <- getArgsAndInitialize
initialDisplayMode $= [ SingleBuffered, RGBMode, WithDepthBuffer ]
initialWindowSize $= Size 500 500
initialWindowPosition $= Position 100 100
_ <- createWindow progName
myInit
reshapeCallback $= Just reshape
displayCallback $= display
keyboardMouseCallback $= Just keyboard
mainLoop
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