[osg-users] Anyone knows about algorithm of osgSim::Overlay?

[Robert Osfield]

Hi Huang,

The technique used in osgSim::OverlayNode simply renders the overlay
subgraph into the texture then uses this texture over the top of the main
terrain scene graph using multi-texturing.  The only part that complicates
the code is that it has support for perspective transformation of the
overlay texture to enable better texture resolution utilization near the
eye point.  The approach is inspired by shadow techniques that do a similar
transformation of the shadow texture.  I am afraid it's too long ago that I
wrote the class for me to remember the exact papers that I read at the time.

Robert.

On 16 September 2017 at 13:19, 张凌寒 <zhanglinghan1987 at 126.com> wrote:

> Hi all,
>         Recently I'm working at the function of draping vectors to the
> terrain. I read the source code of osgEarth1.3 which implements the
> function and found it uses class osgSim::Overlay. However, when I dive into
> osgSim::Overlay, I can't really get what this class wants to do. The only
> thing I know about osgSim::Overlay is that it captures a texture and puts
> it on the terrain. Does anyone know about the algorithm of this class ?  Or
> is there some paper which explains the algorithm? Please help me know.
>
> Thank you.
> Huang
>
>
>
>
>
>
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