Re: [HOpenGL] GL utilities, toolkits, and questions..

On Tue, 09 Jul 2002 21:32:27 +0100 "C.Reinke" wrote:

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* oh, and why is the default stroke font size so huge? I have * to scale it down by a factor of 100, it seems, to get into * natural proportions..

Could you please post some text rendering example? I am not sure to have understood it well. Maybe it's better you send it to my private address.

Sure. Here's the part of my current prototype dealing with Text nodes in the scene graph (where strs is a list of Strings): render context@(RC{t=t,lights=l,sources=srcs,keyb=keyb}) (Text strs) = do pushMatrix scale fontFudge fontFudge fontFudge sequence_ [pushMatrix >> strokeString StrokeRoman str >> popMatrix >> translate gap | str <- strs] popMatrix return (context, Text strs) where fontFudge = 1/105::GLdouble gap = Vector3 0 (-125) 0 :: Vector3 GLdouble So, basically, it's just "strokeString StrokeRoman <your String>", with few variations (e.g., using bitmapped fonts instead). It'll also translate your position to the end of the String. You'll notice that I have to scale down the text to get it roughly to the unit size of GLUT's cubes, and that I use a rather silly nested transformation scope to hide the translations done by stroking the Strings because of the other strangeness I mentioned (the width of stroked Strings being returned as a bitsize..).

I have to say that hopengl is really comfortable, the strong typing gives a different feeling, like you can trust what you just wrote.

No complaints about Sven's work!-) But I think we thank him best by building on the foundations he laid, so that the functionality may be accessed at more abstract levels, e.g. declarative scene graphs compiled down into streams of HOpenGL-instructions, as indicated above. That way, he'll be able to profit from our work as we from his. Currently, it's more like a teaser trailer than anything useful, but I've now added some boring screen shots and code to my FunWorlds page http://www.cs.ukc.ac.uk/people/staff/cr3/FunWorlds/ (the library itself desperately needs some rudimentary documentation before I can release it, and lots of functionality added afterwards, and of course I'll keep testing and modifying the design ideas:).

I am going to write a simple file manager in haskell, it is simple indeed, but I am not able to decide where to place rendered text and how to scale it, so I would like your example.

For a file manager (btw, I've found standard Haskell file access functionality very limited, but GHC's should be a lot more practical), you'll want 2d representations, orthogonal projections, and well-antialiased bitmapped fonts, so your requirements differ from mine - HOpenGL is a wide playing field!-) But GLUT's bitmapped fonts might be an acceptable starting point (just), and are just as easy to use as its stroked fonts. Here are some relevant links http://www.opengl.org/developers/code/features/fontsurvey/ http://www.opengl.org/developers/code/mjktips/TexFont/TexFont.html http://homepages.paradise.net.nz/henryj/code/index.html#FTGL http://oglft.sourceforge.net/ Bindings to one of the latter two would be really nice, but they also seem to add new dependencies (on the libraries themselves, and on the FreeType software they build on..). Also, look through the HOpenGL mailing list archive for the links to OpenGL-based GUIs Sven posted a while ago. Binding to one of those would be of general interest (just as fonts..) and might make the file manager problem easier: http://www.sjbaker.org/steve/omniv/mui_pui_glui.html http://www.cs.unc.edu/~rademach/glui/

I have 0.1 knowledge of opengl, as you might have noticed, but I am willing to learn, don't worry, if you have a working example it's just easier :)

We are all learning, but it's a lot of fun!-) The interface to GLUT fonts is so trivial that its spec is already an example, mostly because there isn't much functionality.. http://www.opengl.org/developers/documentation/glut/index.html (see HOpenGL-1.02/lib/GLUT_Fonts.hs for Sven's adaptation)

If I have a working prototype soon I'll tell it to the M.L. of course.

Looking forward to all news about HOpenGL projects.

There's one thing I forgot to say: I will have some spare time in august, maybe I could writer an haskell interface to one of the font renderers available for opengl.

Is this a good moment, or should I wait for FFI?

If we believe the marketing hype, ghc-5.04.1 will have what it takes, and the FFI spec is stable (they say..). Cheers, Claus