Re: [HOpenGL] (not?) using preservingMatrix

My last post was eaten by this "Nabble Forums" web page! ... 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!) (see the post http://groups.google.com/group/comp.graphics.api.opengl/browse_thread/thread...) jamin1001 wrote:

Sebastian Sylvan wrote:

...

On 1/5/07, jamin1001 wrote:

...

Right, I buy that. But I don't see how the C line

glGetFloatv (GL_MODELVIEW_MATRIX, your_matrix_result) ;

can be done, since it writes a result into your_matrix_result, so I would need something like:

preservingMatrix $ do loadIdentity -- do whatever you want with your your matrix rs <- get ((matrix $ Just $ Modelview 0)::StateVar(GLmatrix GLdouble))

This does indeed compile for me. GHC 6.6.

-- 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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