[vtkusers] Re: Edge (region?) Visibility

[Goodwin Lawlor]

Hi Juan,

You can have a look at a tcl example that backface culls polygons before 
rendering... this allows you to count visible polygons or edges. Its here:

http://www.bioengineering-research.com/vtk/BackfaceCull.tcl

If you need better performance, the cvs version of VTK backface culls 
wireframes... if you render into the openGL feedback buffer you can 
count the visible edges there (Look at how vtkGL2PSExporter does it). 
This could be more hassle than its worth though.

If you'd like a stand alone exe to run the tcl file, try this:

http://www.bioengineering-research.com/vtk/vtkit.htm

hth

Goodwin

Juan Ignacio Sánchez Lara wrote:
> Hello all,
> 
> I've been told to use VTK library and I must admit I'm quite lost, so 
> I'd like to ask you for help.
> 
> I must implement an application which receives polygons and a "camera 
> point" as input (everithing in 2D), and it must return the segments of 
> the polygon edges which are visible from that point. What do you 
> reccomend me to use? The only documentation I've found is the library 
> API, and it's quite hard to begin that way...
> 
> Every kind of help would be greatly appreciated!
> 
> best regards,
> 
> -- 
> Juan Ignacio Sánchez Lara
> Ingeniero Técnico en Informática de Sistemas
> 
> 
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