[android-developers] Re: Incorrect output values with gluUnProject… why?

isn't exist a easiest way to do it...? i think i need a little help
with that algorithm

On Nov 8, 4:03 pm, Streets Of Boston <flyingdutc...@gmail.com> wrote:
> In your 3D model, you have two Z values (for depth). Z-near (the 'location'
> of your screen) and Z-far (the furthest z-plane of your 3D model).
> The user touches the screen and Xs, Ys.
>
> Now call gluUnProject twice:
> gluUnProject(xWin, ((float)screenH)-yWin, *zNear*, modelMatrix,  0,
> projMatrix, 0, mView, 0, *outputCoordsNear*, 0);
> gluUnProject(xWin, ((float)screenH)-yWin, *zFar*, modelMatrix,  0,
> projMatrix, 0, mView, 0, *outputCoordsFar*, 0);
>
> Now you have a *line *in your 3D model that starts at your screen
> 'outputCoordsNear' and ends at 'outputCoordsFar'
> Dust off your geometry-class' books and figure out how to move your Square
> so that (the center of) it will intersect with this line.

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