Re: [Plib-users] Selecting with mouse

[Steve B. <sjb...@ai...>]

David Megginson wrote:
> Steve Baker writes:
> 
>  > Whilst I agree that this is useful - for selection, it's better to use
>  > the OpenGL mechanism because it allows you to select within a rubber-banded
>  > region - and it stands a good chance of being hardware accellerated.
> 
> How would you map from the OpenGL hits back to the scene graph,
> without doing a depth-first search of the whole thing?

My recollection of how it worked with PPE is that I built a table
of OpenGL "name" tags versus SSG node addresses while descending
the scene graph for cull/draw and then when I retrieve the name tags
from the OpenGL pick function, it's a simple lookup table to get
directly to the SSG node.

What vastly complicated PPE was that we needed to be able to pick
each vertex and each edge.  I don't recall how that was done.

----------------------------- Steve Baker -------------------------------
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