[HOpenGL] Re: [Haskell-cafe] Decoupling OpenAL/ALUT packages from OpenGL

[Hugo Gomes]

hmatrix is bloat...

On Sun, May 3, 2009 at 5:58 PM, Tillmann Vogt
<Tillmann.Vogt at rwth-aachen.de>wrote:

> Balazs Komuves schrieb:
>
>
>>
>> On Sun, May 3, 2009 at 12:56 AM, Tillmann Vogt <
>> Tillmann.Vogt at rwth-aachen.de <mailto:Tillmann.Vogt at rwth-aachen.de>>
>> wrote:
>>
>>    Now that you mention it. I just looked through haskell hierachical
>>    libraries and there seems to be no standard data types for vector
>>    math. Am I getting something wrong or is every library that is
>>    using linear algebra stuff using its own data types? So if I use a
>>    numeric library for matrices inside HOpenGL I have to convert around?
>>
>>    I think it would be nice to have data types and functions for dot
>>    produkt, scalar product, norms, ...
>>    together with HOpenGL types.
>>
>>    Currently I am trying to embed a triangulation library from a ten
>>    year old diploma thesis (http://www.dinkla.net/fp/cglib.html) in
>>    my libary (I know that glu has tesselation). The author has
>>    developed a quite big and abstract type structure for all sorts of
>>    computer graphics algorithms and I didn't wanted to copy this into
>>    my library just for triangulation. But it is reasonable. It could
>>    be combined with HOpenGL types to maybe
>>    Data.VectorMath or Data.LinearAlgebra . I would favour the second.
>>
>>
>> The problem is, in my opinion, that the design space of linear algebra
>> libraries is big and complex;
>> thus I don't think a "canonical" linear algebra library is a good idea.
>>
>> There are at least 4 linear algebra libraries on Hackage already:
>>
>> http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hmatrix
>> http://hackage.haskell.org/cgi-bin/hackage-scripts/package/vector-space
>> http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Vec
>> http://hackage.haskell.org/cgi-bin/hackage-scripts/package/vect
>>
>> and they are all very different, and I can easily imagine the usefulness
>> of some more.
>>
> These libraries are different in the way they store data and in the
> interface. vectors-space is abstract, while your library offers an easier
> interface. For example vector-space defines an additive group and an affine
> space while you have a function translate3x.
> But essentially they all implement standard algorithms one learns in a
> computer science course (linear algebra, computer graphics) in university.
>
> I think the best would be to have one abstract library. Then hmatrix
> imports this library and overloads the functions.
> People who want to use the speedy hmatrix lapack binding import it.
> Importing the original abstract library gives an impression of the speed
> differences.
> Then to have your easy interface you reimplement your library by giving the
> user a choice of which library to base it on (the abstract or hmatrix). As
> the last step HOpenGL renames an abstract n-dimensional vector (for n=3) to
> Vertex3 and the I can apply all the useful functions to Vertex3 values.
>
> The disadvantage is of course that someone who wants to find out how
> something works has to read through a chain of types in different files. But
> this can be solved with a good documention that blackboxes everything that
> must not necessarily be understood by everyone. I also hope that one day a
> good IDE will help here.
> The argument that these libraries are fundamentally different is in my
> opinion not valid. I also don't understand why a too general libary would
> open a can of worms.
> Haskell has abstract data types. A Matrix can contain real values or
> polynomials or whatever. A Math person can derive his crazy library with
> overloaded functions. And no one whoe doesn't want to read this has to. I
> also think that most people want to do similar things as can be seen by the
> upper four libraries.
>
>
>> Self-advertisement: The last of the above four is designed especially for
>> graphics use,
>> in particular with OpenGL; but I'm not really satisfied with its current
>> state, so feedback
>> is very welcome!
>>
>> Balazs
>>
>>
> _______________________________________________
> HOpenGL mailing list
> HOpenGL at haskell.org
> http://www.haskell.org/mailman/listinfo/hopengl
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.haskell.org/pipermail/hopengl/attachments/20090504/666d0810/attachment.htm