October 2003 - HOpenGL

ANNOUNCE: HOpenGL 1.05 released
by Sven Panne 16 Nov '03

16 Nov '03

HOpenGL, a Haskell binding for OpenGL and GLUT version 1.05 I am pleased to announce the sixteenth release of the Haskell binding for GL 1.2.1 / GLU 1.3 / GLUT 3.7beta. It offers easy access to *the* industrial strength 3D graphics API and a GUI toolkit. More details about HOpenGL can be found at http://haskell.org/HOpenGL/ This is a compatibility/bug fix release with the following changes: * Fixed a memory allocation bug for GL state queries. * Works with new hierarchical libraries now. * Always use the correct calling convention. * The build system works with recent versions of GHC and GreenCard now. As always, feedback and/or patches are highly welcome. A note for people on the bleeding edge: If you are interested in the future of HOpenGL and its new API, you might wish to build GHC from CVS, configuring with `--enable-hopengl'. This will result in a GHC with two additional packages `OpenGL' and `GLUT'. The APIs have improved quite a bit and are now modeled around the notion of state variables. Furthermore, OpenGL's extension mechanism is now supported on all major platforms, including Linux, Windows and Mac OS X. Note that this is still work in progress, but early feedback would be very useful. Have fun! Sven

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Debian&HOpenGL, undefined symbol: glPixelStorei
by Ville Tirronen 15 Nov '03

15 Nov '03

Hi, I'm trying to get HOpenGL working on a unstable debian box. Since there were suitable packages available (ghc6, ghc6-hopengl) I installed those. After trying to "ghci6 -package GLUT" I get the following error message: Loading package OpenGL ... ghc-6.0.1: can't load .so/.DLL for: GLU (/usr/ X11R6/lib/libGLU.so: undefined symbol: glPixelStorei) With packages for ghc5 this seems to work but I cannot get any example compiled. The result for "ghc5 --make -package GLUT Planet.hs" is: ghc-5.04.3: can't find module `GL' (while processing "Planet.hs") Any help appreciated, Ville Tirronen

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problem with displayCallback and Double buffering
by Marc A. Ziegert 05 Nov '03

05 Nov '03

does anyone else have this problem? i want to use double buffering, but swapBuffers does not seem to work. to set the active window to... the active window (i think that has to work!) does not work, too. but i am able to compile and run glut examples with double buffering written in c. coeus@titan ~/Documents/haskell/hopengl/problem $ ghc -package GLUT -package OpenGL first.hs -lglut coeus@titan ~/Documents/haskell/hopengl/problem $ ./a.out displayModePossible? ...True begin swapBuffers

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Confused about normals
by Patrick Scheibe 14 Oct '03

14 Oct '03

First I want to thank Sven for solving the problem with the missing normals. But now I am a little bit confused. I'm sure to heard about that if you specify the vertexes of a polygon (with glBegin GL_POLYGON in c) counterclockwise then the normalvector is set automatically. That means if you look at a plane the normal vector points to you. Is'nt that true? My example problem seems to show that this is definitly not true. So if I want to use light (and that will be very often) and I have to specify these vectors by myself then I can't use the renderPrimitive Polygon or Quad in situ because the calculation of a normal vector of a polygon isnt that trivial. The simplest way I see is to reduce this calculation to a normal vector calculation of a triangle. So I'm forced to define a new function makePoly taking a list of Points, calculating the normal and draw a polygon with this points. Otherwise I have to write down some points more then one time, the first time in the makenormal-function and in the secont at the render call. 1. Is this the way? 2. Where is it used that normals aren't right-angeled to the polygon-plan? 3. Exists there some higher-level function. With best regards Patrick

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light sources.
by Patrick Scheibe 09 Oct '03

09 Oct '03

Hi everybody. I have problems to get a fixed light source. The light seems to rotate together with my model. Are there anywhere a few examples (these under GLUT/examples/.... are not so helpful) where I can have a look on other peoples work? Greetings Patrick

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API names [was: ghc-6.0.1 and OpenGL enabled]
by Sven Panne 09 Oct '03

09 Oct '03

Thanks for all your replies, naming is obviously still one of the hottest topics in CS... Here are my thoughts: "locally" is (as already mentioned) too general, and "withFoo" is traditionally used for functions with a signature of the form: withFoo :: Foo -> ... But the current matrix is implicit, so this would not be a good choice for the combination of glPushMatrix/glPopMatrix. We are basically left with: saveFoo might not give a hint that a Foo is restored rememberingFoo same comment as above applies preservingFoo sounds good to me, but might be a bit long The current story for the combined GL calls is: glBegin/glEnd renderPrimitive glNewList/glEndList defineList glPushName/glPopName pushName glPushMatrix/glPopMatrix matrixExcursion glPushAttrib/glPopAttrib saveServerState glPushClientAttrib/glPopClientAttrib saveClientState The first two sound right to me, the third is actually a "withFoo", and the last three should be named in a consistent way. Combining your proposals I suggest: glBegin/glEnd renderPrimitive glNewList/glEndList defineList glPushName/glPopName withName glPushMatrix/glPopMatrix preservingMatrix glPushAttrib/glPopAttrib preservingAttrib glPushClientAttrib/glPopClientAttrib preservingClientAttrib Does this sound OK, especially for the native speakers on this list? Cheers, S.

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RE: [HOpenGL] ghc-6.0.1 and OpenGL enabled
by Sumskas, Peter (Peter) 09 Oct '03

09 Oct '03

> -----Original Message----- > From: Carl Witty [mailto:cwitty@newtonlabs.com] > > On Wed, 2003-10-08 at 10:56, Nick Name wrote: > > Alle 16:20, mercoledì 8 ottobre 2003, Alastair Reid ha scritto: > > I was just going to suggest withCurrentMatrix or withMatrix :) > > I don't like withCurrentMatrix ("with current" sounds like it should be > a no-op). withLocalMatrix would be good; for a long, descriptive name, > you could use whileRememberingCurrentMatrix (shorter versions might be > whileRememberingMatrix or rememberingCurrentMatrix). > > Carl Witty I'd vote for "preserving" -it is one letter shorter than "remembering" and I feel, if I understand the discussion, that preserve is a better fit meaningwise than remembering. Eg: preservingMatrix, or preservingCurrentMatrix P.

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ghc-6.0.1 and OpenGL enabled
by Patrick Scheibe 08 Oct '03

08 Oct '03

Hi everyone. At this time the situation of HOpenGL and ghc --enable-hopenGl is very confusing to me. I tried to install the new HOpenGL package from Sven. But the make install doesnt seem to work. When I tried to compile a simple example of the Redbook the linker stops because of undefiened references to some c-functions. If theres some time I post the exact error-message .. Now I use the openGl that comes with the ghc and I've started to map the functions of HOpenGl to the corresponding ghc-openGl functions. Now my question: The push and popMatrix functions dont seem to be there in future. What should I use instead of this? If I have the following code: pushMatrix GL.translate $ vec2Vector3 pos let ANGLE adir = toAngle dir ANGLE aheadangle = toAngle headangle rotate adir $ Vector3 0.0 0.0 (1.0 :: GLfloat) callList $ head ownbodyDL rotate aheadangle $ Vector3 0.0 0.0 (1.0 :: GLfloat) callList $ ownheadDL popMatrix what are the lines I have to write, that ghc doesnt show errors? Cheers Patrick

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Re: HOpenGL Digest, Vol 1, Issue 146
by Manuel Garcia Rodriguez 08 Oct '03

08 Oct '03

> [...]As Wolfgang has already pointed out, using > matrixExcursion is the way to go. >(BTW, I'm not very happy with this name, any > suggestions are highly appreciated.)[...] newMatrix, withNewMatrix ___________________________________________________ Yahoo! Messenger - Nueva versión GRATIS Super Webcam, voz, caritas animadas, y más... http://messenger.yahoo.es

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Pre-Call for Contributions -- HC&A Report (November 2003 edition)
by C.Reinke 02 Oct '03

02 Oct '03

[apologies for multiple copies - experience has shown that not all Haskellers can be reached via the main Haskell list anymore] An entry for your diaries (no other action required right now): ------------------------------Pre-Call-------------------------------- Your contributions to the November 2003 edition of the Haskell Communities & Activities Report will be invited soon. http://www.haskell.org/communities/ Submissions are welcome between 20th and 31st of October ---------------------------------------------------------------------- The real Call for Contributions will follow closer to the submission window, in about two weeks. This is just an early warning. You will need to plan about 15 minutes for composing your contribution, which would be a brief, ASCII-format, description of your Haskell activities (see earlier editions for plenty of examples). Cheers, Claus (current editor of HC&A Reports)

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