[osg-users] World space normal.

[Robert Osfield]

Hi Marlin,

It can be done, but I strongly recommend that you don't go transforming
vertex or normal data into world coordinates in the shader.  I know there
are some published algorithms that do this but it's a really bad practice
and you shouldn't follow it as precision issues on only proper dataset will
cause mayhem - the do the cals in world coordinates only for datasets with
a local origin, it's just a mess for any real-word datasets.

Cheers,
Robert.




On Wed, 11 Jul 2018 at 14:17, Rowley, Marlin R <marlin.r.rowley at lmco.com>
wrote:

> I have a world space vertex computed as follows:
>
>
>
> WorldVertex = osg_ViewMatrixInverse * gl_ModelViewMatrix * aVertex;
>
>
>
> I would like to get the world space normal from this vertex.  Is there an
> equivalent osg_* matrix that does the same thing?
>
>
>
> I tried this:
>
>
>
> NormalWorld = gl_NormalMatrix * gl_Normal;
>
>
>
> But I know that is only putting the normal in view space.
>
>
>
> ----------------------------------------
>
> Marlin Rowley
>
> Software Engineer, Staff
>
> [image: cid:image002.jpg at 01D39374.DEC5A2E0]
>
> *Missiles and Fire Control*
>
> 972-603-1931 (office)
>
> 214-926-0622 (mobile)
>
> marlin.r.rowley at lmco.com
>
>
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