[PD] texturing a circular image onto a hemisphere in GEM

[Alex]

so to make this easy think of a square texture that has a picture the
globe centered inside it.
i want to take that picture and map the flat image of the globe onto a
hemisphere so that you see [in this virtual world] 1/2 of a globe,
warped so that, in the virtual world, it looks correct.

-Alex

On 10/15/07, marius schebella <marius.schebella at gmail.com> wrote:
> Hi alex,
> I am not sure what you're trying to do, but I am eager to help you...
> do you want to project the video onto a wall/ceiling hemisphere inside a
> real room? or are you talking about virtual projections?
> I guess what you have to do first is distort the circled video back into
> a square and then use that to texture the sphere.
> marius.
>
>
> sphere with a ? is it just the mapping on the spherefor any distortion you
>
> Alex wrote:
> > Maybe a different subject will inspire some help?
> >
> > basically, I have video that was shot on a mirrored spherical ball..
> > this gives a circular image inside a rectangular video, I've figured
> > out how to crop it so that I just get the square that surrounds the
> > circle, but I cannot figure out how to correctly map this texture onto
> > a sphere so that it is only on one hemisphere and so that the circle's
> > circumference is on a "great circle" of the sphere? [ie it the circle
> > is warped out so that it becomes a hemisphere].
> >
> > I figure maybe I have to do some GEMgl stuff for this?
> >
> > if anyone has done this, would you please share?
> >
> > If not, any advice?
> >
> > Thanks,
> > -Alex
> >
> >
> > On 10/10/07, Alex <x37v.alex at gmail.com> wrote:
> >> I have some panoramic video that I want to use to texture a hemisphere
> >> [or rather, the bottom half of a sphere].
> >>
> >> I cannot simply texture the sphere with the video because the warping
> >> is not correct.. it seems that I need some sort of non-rectangular
> >> warping of the image before I texture the object, or a non-rectangular
> >> mapping of the texture onto the sphere.
> >>
> >> Any ideas or advice?  Does anyone else have experience working with
> >> panoramic video in Gem?
> >>
> >> -Alex
> >>
> >
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