[ redirected to hopengl mailing list ] Gracjan Polak wrote:

Hi all,

I'd like to make some use of OpenGL with Haskell (under Win2000). Here is some code:

module Main where import Graphics.Rendering.OpenGL.GL import Graphics.Rendering.OpenGL.GLU import Graphics.UI.GLUT

main = do ver <- get gluVersion putStrLn ver

getArgsAndInitialize fullScreen wnd <- createWindow "Hello World"

vertex (Vertex2 (100::GLint) 100) return ()

Compilation (linking) fails with:

$ ghc --make openglapp.hs -o openglapp.exe Chasing modules from: openglapp.hs Compiling Main ( openglapp.hs, openglapp.o ) Linking ... c:/ghc/ghc-6.2/libHSGLUT.a(Initialization__158.o)(.text+0x123):ghc16024.hc: unde fined reference to `glutInit@8' c:/ghc/ghc-6.2/libHSGLUT.a(Window__61.o)(.text+0x33):ghc14736.hc: undefined refe rence to `glutFullScreen@0' c:/ghc/ghc-6.2/libHSGLUT.a(Window__53.o)(.text+0x85):ghc14736.hc: undefined refe rence to `glutCreateWindow@4'

Manually adding -lglut -lglut32 does not help. Libraries libglut32.a and libglut.a are there, they contain needed symbols but with '_' prepended, like _glutInit@8.

Functions from GL and GLU link perfectly. They do even work correctly when run. Only GLUT ones do not :(

Has anybody compiled anything for GL recently? Google pointed me only to some old, not relevant any more, material.

Am I missing something obvious here?

GHC 6.2, installer for Window taken from www.haskell.org, Win2000 Professional.

It compiles fine with GHC 6.2.1 on my Win2k box, you might want to update your GHC installation. There have been quite a few bug fixes, so it might be worth it even when you are not using OpenGL/GLUT. Does it work with 6.2 when you add -O? Just curious... Apart from that, there are a few things you should change in your code: * GL/GLU state can only be accessed after you have a rendering context, i.e. after createWindow * fullScreen only works when you have a current window, i.e. after createWindow * Rendering should only be done in the display callback * The vertex call should probably be within a renderPrimitive. Perhaps Sven Panitz' tutorial might help a bit: http://www.tfh-berlin.de/~panitz/hopengl/ A more up-to-date version of the tutorial is available from the fptools CVS repository, but building it requires some unusual tools, BTW. Cheers, S.