[vtkusers] vtk-theory: some questions about "behind the curtains"

[Cory Quammen]

On Thu, Aug 18, 2011 at 3:19 AM, Fabian <fabian-richter at gmx.de> wrote:
> Hello all,
>
> thanks to Your help I managed to get my code running. But it brings some new
> questions which I need advice with:
>
> 1. Each plane consits 2 polygons, right? Then 1000 planes make 2000
> polygons; a number which my hardware should deal with easily; but frame rate
> is poor with (just) 2000 polygons. Can it be, that I chose the wrong
> strategy: I create a vector with 1000 planes then 1000 datamapper then 1000
> actors...all in one loop. Thus maybe I should say, I created 1000 piplines.
> Is there a better way? I hoped to measure my hardware-redndering-power with
> some million polygons!

VTK is slow when you have many actors, as you have discovered. I'm not
familiar with what you are trying to do, but if it involves rendering
a number of rectangles, perhaps of different sizes and at different
orientations, you could use a vtkGlyph3D filter instead. See
http://www.vtk.org/Wiki/VTK/Examples/Cxx/Visualization/OrientedGlyphs

> 2. Is it possible to parallize the rendering process? I got 4 cores but only
> one is used for rendering.

All the rasterization is performed on your GPU, so only 1 core is
really needed to manage the GPU.

> 3. I am not sure about texuring. When I take a BMP, lets say 4 Mb; is the
> internal texture volume 4 Mb as well (beacause its Bitmap?!). I couldnt find
> a way to get the texture data volume (exept reading the filsize of the
> picture on the HDD; but I am not sure if its the same!

That seems like a reasonable assumption. I don't know a general way of
checking GPU memory usage. Perhaps your GPU driver has some utilities
to show you how much memory a texture uses?

Cory

> Thank You very much for Your help; every advice is welcome!
>
> Greetings,
> Fabian
>
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-- 
Cory Quammen
Research Associate
Department of Computer Science
The University of North Carolina at Chapel Hill