[osg-users] EXTERNAL: Re: Value of a variable in shaders?

[Robert Osfield]

On Fri, 28 Sep 2018 at 14:48, Rowley, Marlin R <marlin.r.rowley at lmco.com>
wrote:

> LOL @ mis-reading my question. 😊
>

My best excuses is speed reading and trying to do too many things at once
:-)


> How would you check the values of vertices?  I just need to see the
> transformed values of a vertex.
>

One way would be to use a draw callback attached to the program
osg::Geometry that reports the current ModelView and Projection matrices
and the list of vertices, at least then you could double check the input
values.

Checking the vertices on GPU isn't don't something that is easy at runtime
without changing the rendering quite extensively such as using
Transfom_Feedback:

    https://www.khronos.org/opengl/wiki/Transform_Feedback

The other possibility would be to see what tools are available on your
OS/hardware/driver combination.
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