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/831ee85b6f97eb15/2de3e6d9c6a1a9e5)
Sebastian Sylvan wrote:
On 1/5/07, jamin1001 <jamin1001@yahoo.com> 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
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