[vtk-developers] Geocoordinate System Filter, 2D Text Manager, 2D Text Preformance, and Buffered Hardware Picking

Philip Schuchardt ohc at vt.edu
Wed Dec 19 11:22:42 EST 2007

On Wednesday 19 December 2007 10:13 am, Sean McBride wrote:
> On 12/18/07 4:18 PM, Philip Schuchardt said:
> >-- 2D Text Manager --
> >I've written a class that managers 3D anchored, 2D text actors.  It keeps
> >multiple text actors from overlapping each other.  It also support
> > Z-buffer checking, which keeps "hidden" 2D text actors from showing.
> By any chance, does your text code support Unicode or just ASCII?I'm using 
vtkTextActor's which I believe are ASCII.  But vtk uses ftgl which, 
I though, supports unicode.  I definitely, will be looking into this because 
my program need so support multiple languages.  

Both our problems are pipeline issues.  Unfortunately, they are unrelated.  
Your problem is creating and caching 3D geometry.  Where as my problem (I 
think), is to many glPixmap calls.  I think, my problem can be fixed putting 
all the opengl calls into displaylist. This way, the calls are stored on the 
graphics card, instead of sending them over CPU to GPU pipeline everytime a 
frame is rendered.

Philip Schuchardt

> >I've also had performance issues while displaying 100's of 2D text
> actors, at
> >once.  I think it's a openGL pipeline issue.  Does vtk/ftgl use display
> lists
> >for 2D text actors?  If it doesn't, I think display lists would greatly
> >improved 2D text actors rendering performance.
> I don't know if it's related, but we also found performance problems
> with text, detailed here:
> <http://public.kitware.com/Bug/view.php?id=5891>

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