Remi Arnaud (remi++at++remi.asd.sgi.com)
Thu, 19 Sep 1996 10:57:11 -0700
> I have noticed that when loading my scene the texture memory goes beyond
> the 4Mb limit.
> I get 134% texture memory use in the pfNotify.
>
> Since all my textures appear to be correct... should I worry?
>
> Does it decrease the application's performance?
> What can I do to avoid it?
This indicates that the texture occupation is bigger than the texture memory,
and therefore the texture will be paged from the Main memory to the texture
memory when Performer needs it.
It can decrease A LOT the performances if you use all your texture on the same
image, because the texture paging will occur inside a frame. If what you are
looking to does not contain more than the texture memory size, only the first
frame will page in textures, and then you are OK.
Now, you have *only* 134% of texture memory usage, so it should be easy to go
under 100% by reducing some texture sizes.
This is a great occasion for me to say:
/----------------------------------\
| DO NOT WASTE YOUR TEXTURE MEMORY |
\----------------------------------/
- Not using power of 2 textures sizes forces OpenGL to use the immediate
bigger power of 2 size. Resulting in a BIG loss of texture memory.
Many time [when not using texture repetition] textures can be grouped
in the same file, which size is power of 2 size. This also helps reducing the
number of texture in the database, wich improves a lot the performances.
- Are your texture sizes coherent ? Using a 256x256 texture for a 30
centimeter wheel and a 128x32 for a kilometer long runway for example is
generally not a good idea.
- Are you sure all your textures have to be mip-mapped ? if you use a pfLOD
that switch a texture object to a non texture one, the mip-map created may
never be used.
- Use detail textures. If you want more resolution when you are near an
object, try using detail texture instead of growing the size of the original
texture.
Also, for the lucky Performer users on Infinite Reality that want to page A
LOT of texture: use ClipMapping ! [performer 2.1]
-- Remi
--
o o Remi ARNAUD - Silicon Graphics, Performer, Advanced Systems Dev o o o o Mail Stop 590 - 2011 N. Shoreline Boulevard, Mountain View, CA94043 o o o o Email: remi++at++asd.sgi.com - Tel: (415) 933 6208 - Fax: (415) 965 2658 o o
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