- HOpenGL - Haskell.org

Re: [HOpenGL] Newbie: Difference between $= and <- operators?
by Jeff Heard 26 Apr '09

26 Apr '09

the $= only works for OpenGL state variables, whereas <- won't work for them. The difference is that $= is implemented by every member of the SettableStateVar class differently, so that there may be extra functionality going on under the hood. The <- operator on the other hand always has the same meaning (relatively speaking -- it's possible to override this), in that it is a substitude for a <- someAction is the same as someAction >>= \a -> {- the rest of the do expression -} -- Jeff 2009/3/20 Mark Spezzano <mark.spezzano(a)chariot.net.au>: > Hi, > > > > What is the difference between the $= operator and the <- operator > > > > Both seem to read “assign to” but surely there is a difference. > > > > What should I use when? > > > > I want to create an animation that reads some coordinate (state-ful) data. > > > > Should I use $= or <- ? > > > > Cheers, > > > > Mark Spezzano > > > > No virus found in this outgoing message. > Checked by AVG. > Version: 7.5.557 / Virus Database: 270.11.20/2012 - Release Date: 19/03/2009 > 12:26 PM > > _______________________________________________ > HOpenGL mailing list > HOpenGL(a)haskell.org > http://www.haskell.org/mailman/listinfo/hopengl > >

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GLU.Tessellator crashes
by Jules Bean 26 Apr '09

26 Apr '09

Hi, I've just written some code which uses 'tessellate' from Graphics.Rendering.OpenGL.GLU.Tessellation and whilst it works exactly as expected on simple data sets, it gives a bus error on larger ones (not that large - e.g. 150 points). This might be a bug in my OS's glu implementation, but I'm also inclined to suspect a bug in all the peeks and pokes HOpenGL uses to handle the data for the callbacks. I don't actually use the callback data (I've set all the data to (0 :: Int) only because there is no storable instance for ()). Does anyone have a success story with this function? Has anyone used it successfully on larger polygons? Jules

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Convex polygons
by Rafael Cunha de Almeida 22 Mar '09

22 Mar '09

I'm reading the red book and it says opengl cannot render convex polygons. Yet, when I compile this code: renderPrimitive Polygon $ do vertex $ Vertex2 0 (0::GLfloat) vertex $ Vertex2 0 (3::GLfloat) vertex $ Vertex2 4 (3::GLfloat) vertex $ Vertex2 3 (1.5::GLfloat) vertex $ Vertex2 4 (0::GLfloat) The convex polygon is displayed correctly. Does hopengl do something behind the scenes or I just "lucked" out that my opengl/hardware can handle this particular convex polygon case?

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Newbie: Difference between $= and <- operators?
by Mark Spezzano 20 Mar '09

20 Mar '09

Hi, What is the difference between the $= operator and the <- operator Both seem to read “assign to” but surely there is a difference. What should I use when? I want to create an animation that reads some coordinate (state-ful) data. Should I use $= or <- ? Cheers, Mark Spezzano No virus found in this outgoing message. Checked by AVG. Version: 7.5.557 / Virus Database: 270.11.20/2012 - Release Date: 19/03/2009 12:26 PM

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Re: [HOpenGL] OpenGL and Cabal installation
by Balazs Komuves 18 Mar '09

18 Mar '09

Hello, I'm not sure about Cabal, but the following should work (point 4 is the critical step): 1) Download the (Haskell) GLUT source from Hackage ( http://hackage.haskell.org/packages/archive/GLUT/2.1.1.2/GLUT-2.1.1.2.tar.gz ) 2) Unpack it into some directory, for example C:\OpenGL\GLUT-2.1.1.2 (make sure that the path does not contain spaces; MSys does not like them) 3) You will need the header files from the (not-haskell) GLUT source, which you can download form http://www.opengl.org/resources/libraries/glut/glut37.zip Unpacke this too, say C:\OpenGL\GLUT-3.7 4) Set the environment variables (I don't know how to that on Vista, but on XP you can do that using Control Panel / System / ...) C_INCLUDE_PATH to have C:\OpenGL\GLUT-3.7\include and LIBRARY_PATH to have C:\OpenGL\GLUT-3.7\lib 5) You should probably build the (not-haskell) GLUT library, because I guess the binaries are not included in the source; or you can download the binaries from the same place and but them into the directory C:\OpenGL\GLUT-3.7\lib 6) Now you can start MSys and build the Haskell GLUT package from the source: $ runghc Setup.hs configure $ runghc Setup.hs build $ runghc Setup.hs install Cabal install may work too. Of course, all this assuming that you have the OpenGL package already built, and the system can find the OpenGL headers. If not, then do the same for OpenGL (except you won't need the C source, but some kind of SDK instead). And yes, it's painful. OpenGL/GLUT used to be bundled with GHC, but they dropped it (among others) because the library maintainance cost is too high for them; they want to concentrate on the compiler (which is understandable). And the promised "Haskell platform" which should solve the problem is nowhere in sight... Balazs 2009/3/18 Mark Spezzano <mark.spezzano(a)chariot.net.au> > Hi all, > > > > I’m trying desperately to get OpenGL up and running. > > > > I type > > >cabal.exe configure and get the following > > > > ... > > checking GL/glut.h usability... no > > checking GL/glut.h presence... no > > checking for GL/glut.h... no > > checking for GLUT library... no > > checking for GL/glut.h... (cached) no > > checking GLUT/glut.h usability... no > > checking GLUT/glut.h presence... no > > checking for GLUT/glut.h... no > > configure: error: no GLUT header found, so this package cannot be built > > See `config.log' for more details. > > > > Where is it looking for these glut.h files? I’ve tried putting them > everywhere in my PATH but msys won’t find them. > > > > Cheers, > > > > Mark Spezzano > > No virus found in this outgoing message. > Checked by AVG. > Version: 7.5.557 / Virus Database: 270.11.18/2008 - Release Date: > 17/03/2009 4:25 PM > > _______________________________________________ > HOpenGL mailing list > HOpenGL(a)haskell.org > http://www.haskell.org/mailman/listinfo/hopengl > >

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OpenGL Linking Issue
by Mark Spezzano 18 Mar '09

18 Mar '09

Hi, I hope I’m posting to the right forum. I’ve got OpenGL up and running on my Windows Vista machine (finally!) and it runs perfectly well under Eclipse, bringing up a window with a rendered image as expected. The only issue starts when I try to compile the program without Eclipse (using GHC rather than GHCi like Eclipse does). I type: C:\Users\Mark\workspace2\OpenGLPractice\src>ghc --make Test1.hs And get the following output Linking Test1.exe ... C:\Program Files\Haskell\GLUT-2.1.1.2\ghc-6.10.1/libHSGLUT-2.1.1.2.a(Extensions. o):fake:(.text+0xcc): undefined reference to `glutGetProcAddress@4' collect2: ld returned 1 exit status What’s happening here? Obviously it’s a linking issue, but I was wondering whether I need to include some library or file or option to ghc so that it links correctly. Cheers, Mark Spezzano No virus found in this outgoing message. Checked by AVG. Version: 7.5.557 / Virus Database: 270.11.18/2008 - Release Date: 17/03/2009 4:25 PM

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OpenGL and Cabal installation
by Mark Spezzano 17 Mar '09

17 Mar '09

Hi all, I’m trying desperately to get OpenGL up and running. I type >cabal.exe configure and get the following ... checking GL/glut.h usability... no checking GL/glut.h presence... no checking for GL/glut.h... no checking for GLUT library... no checking for GL/glut.h... (cached) no checking GLUT/glut.h usability... no checking GLUT/glut.h presence... no checking for GLUT/glut.h... no configure: error: no GLUT header found, so this package cannot be built See `config.log' for more details. Where is it looking for these glut.h files? I’ve tried putting them everywhere in my PATH but msys won’t find them. Cheers, Mark Spezzano No virus found in this outgoing message. Checked by AVG. Version: 7.5.557 / Virus Database: 270.11.18/2008 - Release Date: 17/03/2009 4:25 PM

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Re: [HOpenGL] Haksell, OpenGL on Windows configuration
by Hugo Gomes 17 Mar '09

17 Mar '09

Hey Mark, im not sure if this helps: http://netsuperbrain.com/blog/posts/freeglut-windows-hopengl-hglut/ 2009/3/17 Mark Spezzano <mark.spezzano(a)chariot.net.au> > Hi, > > > > Can someone PLEASE help me to understand exactly how to configure OpenGL on > Window using Haskell. I'm using Eclipse IDE. > > > > When I try to run the file Test1.hs in GHCi then I get the following error: > > Loading package syb ... linking ... done. > > Loading package base-3.0.3.0 ... linking ... done. > > Loading package array-0.2.0.0 ... linking ... done. > > Loading package containers-0.2.0.0 ... linking ... done. > > Loading package OpenGL-2.2.1.1 ... can't load .so/.DLL for: GL (addDLL: > could not load DLL) > > Prelude Main> > > > > I've copied the GLUT dll into Windows/System32. > > > > Is there some flag or option that I need to enable to tell Haskell where to > go to link in the library. What do I do with the other .h and .lib files > from GLUT? > > > > Thanks > > > > Mark > > > > > > No virus found in this outgoing message. > Checked by AVG. > Version: 7.5.557 / Virus Database: 270.11.15/2004 - Release Date: > 16/03/2009 7:04 AM > > _______________________________________________ > HOpenGL mailing list > HOpenGL(a)haskell.org > http://www.haskell.org/mailman/listinfo/hopengl > >

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Re: [HOpenGL] Haksell, OpenGL on Windows configuration
by Conal Elliott 17 Mar '09

17 Mar '09

Hi Mark, When I was on Windows, I had to get the sources of the OpenGL and GLUT packages add an "extra-libraries" line to each of OpenGL.buildinfo.in GLUT.buildinfo.in. Seems to be a bug in the recent library releases. For GLUT, I think I added extra-libraries: glut32 I forget what the library name was for OpenGL. To find out whether these extra-libraries are already listed, try the following shell commands: ghc-pkg describe OpenGL | grep extra ghc-pkg describe GLUT | grep extra I was completely stumped until Sigbjorn Finne suggested there might be missing extra-libraries. - Conal 2009/3/17 Mark Spezzano <mark.spezzano(a)chariot.net.au> > Hi, > > > > Can someone PLEASE help me to understand exactly how to configure OpenGL on > Window using Haskell. I'm using Eclipse IDE. > > > > When I try to run the file Test1.hs in GHCi then I get the following error: > > Loading package syb ... linking ... done. > > Loading package base-3.0.3.0 ... linking ... done. > > Loading package array-0.2.0.0 ... linking ... done. > > Loading package containers-0.2.0.0 ... linking ... done. > > Loading package OpenGL-2.2.1.1 ... can't load .so/.DLL for: GL (addDLL: > could not load DLL) > > Prelude Main> > > > > I've copied the GLUT dll into Windows/System32. > > > > Is there some flag or option that I need to enable to tell Haskell where to > go to link in the library. What do I do with the other .h and .lib files > from GLUT? > > > > Thanks > > > > Mark > > > > > > No virus found in this outgoing message. > Checked by AVG. > Version: 7.5.557 / Virus Database: 270.11.15/2004 - Release Date: > 16/03/2009 7:04 AM > > _______________________________________________ > HOpenGL mailing list > HOpenGL(a)haskell.org > http://www.haskell.org/mailman/listinfo/hopengl > >

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Dynamic link error with OpenGL
by Mark Spezzano 17 Mar '09

17 Mar '09

Hi, I’m using OpenGL and FreeGLUT on Windows Vista, using the Eclipse IDE. I’m getting a dynamic linking error below. It’s probably something really simple, but I can’t work it out... Loading package base ... linking ... done. Loading object (dynamic) glut32 ... done Loading object (dynamic) glu32 ... done Loading object (dynamic) opengl32 ... done final link ... done Ok, modules loaded: Main. Prelude Main> main Loading package syb ... linking ... done. Loading package base-3.0.3.0 ... linking ... done. Loading package array-0.2.0.0 ... linking ... done. Loading package containers-0.2.0.0 ... linking ... done. Loading package OpenGL-2.2.1.1 ... can't load .so/.DLL for: GL (addDLL: could not load DLL) Prelude Main> Thanks Mark No virus found in this outgoing message. Checked by AVG. Version: 7.5.557 / Virus Database: 270.11.15/2004 - Release Date: 16/03/2009 7:04 AM

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