1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
{-
DList.hs (adapted from list.c which is (c) Silicon Graphics, Inc)
Copyright (c) Sven Panne 2002-2005 <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 how to make and execute a
display list. Note that attributes, such as current
color and matrix, are changed.
-}
import System.Exit ( exitWith, ExitCode(ExitSuccess) )
import Graphics.UI.GLUT
myInit :: IO DisplayList
myInit = do
[listName] <- genObjectNames 1
-- resolve overloading, not needed in "real" programs
let color3f = color :: Color3 GLfloat -> IO ()
vertex2f = vertex :: Vertex2 GLfloat -> IO ()
translatef = translate :: Vector3 GLfloat -> IO ()
defineList listName Compile $ do
color3f (Color3 1 0 0) -- current color red
renderPrimitive Triangles $ do
vertex2f (Vertex2 0 0)
vertex2f (Vertex2 1 0)
vertex2f (Vertex2 0 1)
translatef (Vector3 1.5 0.0 0.0) -- move position
shadeModel $= Flat
return listName
drawLine :: IO ()
drawLine = do
-- resolve overloading, not needed in "real" programs
let vertex2f = vertex :: Vertex2 GLfloat -> IO ()
renderPrimitive Lines $ do
vertex2f (Vertex2 0.0 0.5)
vertex2f (Vertex2 15.0 0.5)
display :: DisplayList -> DisplayCallback
display listName = do
-- NOTE: The following 'loadIdentity' is missing in the original
-- example, but without it the translatef calls accumulate and
-- the graphics wander out of the window after a few redraws...
loadIdentity
clear [ ColorBuffer ]
-- resolve overloading, not needed in "real" programs
let color3f = color :: Color3 GLfloat -> IO ()
color3f (Color3 0 1 0) -- current color green
sequence_ (replicate 10 (callList listName)) -- draw 10 triangles
drawLine -- is this line green? NO!
-- where is the line drawn?
flush
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 ortho2D 0.0 2.0 (-0.5*hf/wf) (1.5*hf/wf)
else ortho2D 0.0 (2.0*wf/hf) (-0.5) 1.5
matrixMode $= Modelview 0
loadIdentity
keyboard :: KeyboardMouseCallback
keyboard (Char '\27') Down _ _ = exitWith ExitSuccess
keyboard _ _ _ _ = return ()
-- Open window with initial window size, title bar,
-- RGBA display mode, and handle input events.
main :: IO ()
main = do
(progName, _args) <- getArgsAndInitialize
initialDisplayMode $= [ SingleBuffered, RGBMode ]
initialWindowSize $= Size 650 50
createWindow progName
listName <- myInit
reshapeCallback $= Just reshape
displayCallback $= display listName
keyboardMouseCallback $= Just keyboard
mainLoop
|
