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
|
-- #hide
--------------------------------------------------------------------------------
-- |
-- Module : Graphics.UI.GLUT.Extensions
-- Copyright : (c) Sven Panne 2002-2005
-- License : BSD-style (see the file libraries/OpenGL/LICENSE)
--
-- Maintainer : sven.panne@aedion.de
-- Stability : provisional
-- Portability : portable
--
-- This is a purely internal module for handling an OpenGL-like extension
-- mechanism for GLUT.
--
--------------------------------------------------------------------------------
module Graphics.UI.GLUT.Extensions (
FunPtr, unsafePerformIO,
Invoker, getProcAddress, getProcAddressInternal -- used only internally
) where
import Foreign.C.String ( CString, withCString )
import Foreign.Ptr ( FunPtr, nullFunPtr )
import System.IO.Unsafe ( unsafePerformIO )
--------------------------------------------------------------------------------
type Invoker a = FunPtr a -> a
getProcAddress :: String -> String -> IO (FunPtr a)
getProcAddress ext call =
throwIfNull ("unknown GLUT call " ++ call ++ ", check for " ++ ext) $
getProcAddressInternal call
throwIfNull :: String -> IO (FunPtr a) -> IO (FunPtr a)
throwIfNull msg act = do
res <- act
if res == nullFunPtr
then ioError (userError msg)
else return res
getProcAddressInternal :: String -> IO (FunPtr a)
getProcAddressInternal call = withCString call hs_GLUT_getProcAddress
foreign import ccall unsafe "hs_GLUT_getProcAddress" hs_GLUT_getProcAddress
:: CString -> IO (FunPtr a)
|
