unsafeInterleaveIO and OpenGL

[Peter Verswyvelen]

I'm experiencing strange behavior when executing some Haskell OpenGL code inside unsafeInterleaveIO.

For example,

        vp <- get GL.viewport

returns garbage, as if the opengl context is not correctly set.

Is this to be expected? Or is it likely a bug on my side?

Thanks,
Peter



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[Henning Thielemann]

On Fri, 9 May 2008, Peter Verswyvelen wrote:

> I'm experiencing strange behavior when executing some Haskell OpenGL code
> inside unsafeInterleaveIO.
>
> For example,
>
>       vp <- get GL.viewport
>
> returns garbage, as if the opengl context is not correctly set.

Sounds reasonable. 'unsafeInterleaveIO' defers computation of 'vp' until
it is actually needed. At this time the viewport might have changed.
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[Peter Verswyvelen]

> Sounds reasonable. 'unsafeInterleaveIO' defers computation of 'vp'
> until it is actually needed. At this time the viewport might have
> changed.
That sound reasonable indeed, but the viewport does not change and the
values I get are really random. I'll try to make minimal example to
demonstrate the problem.

Thanks,
Peter

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