Re: [HOpenGL] (not?) using preservingMatrix

Thank you very much. I appreciate the detailed response and extra tips! Jamin Sebastian Sylvan wrote:

On 1/5/07, jamin1001 wrote:

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My last post was eaten by this "Nabble Forums" web page!

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Ah, you're right. What didn't compile for me was this additional line after the preservingMatrix call: putStr $ "Result matrix: " ++ (show rs) ++ "\n"

Instead, I want to return that value to use outside the call. This is what I was after, I think:

rs2 <- preservingMatrix $ do loadIdentity -- do whatever you want with your your matrix rs <- get ((matrix $ Just $ Modelview 0)::StateVar(GLmatrix GLdouble)) return (rs) putStr $ "Result matrix: " ++ (show rs2) ++ "\n"

Now, as for question #2, are there any pre-made ways to transform a vector with a matrix, or do I have to do it by hand (same goes for cross product!)

Not with OpenGL. If you go to the haskell.org website and check out the libraries page I'm sure you'll find plenty of linear algebra libraries. This is a problem that you have to face in any language, btw, at least any language which doesn't include linear algebra operations.

Oh, and also

do bar xs <- foo return xs

is equal to

do bar foo

I'e you can loose the arrow and the "return".

/S -- Sebastian Sylvan +46(0)736-818655 UIN: 44640862 _______________________________________________ HOpenGL mailing list HOpenGL@haskell.org http://www.haskell.org/mailman/listinfo/hopengl

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