Hi Christoph,
On Mon, 2005-07-18 at 17:07 +0200, Christoph Anthes wrote:
> Hello,
>
> I have a problem runing OpenSG 1.4 on our Onyx system. I was trying to
> measure the performance of the system using different texture sizes.
> Somehow textures seam to slow down the system immensely. With models
> without textures we produce framerates of 20 frames with 200.000
> triangles. With models with textures we run into framesrates of 0.5
> frames with 1.000 polys. I tried to see wether the prformance of the
> system is that bad in general and ran a model which ran in OpenSG
> something below one frame and in Perfomer it runs at roughly 25 frames.
> So the graphics HW can't be that bad. What might be the problem ? Are
> there any ideas on how to solve it ? Attached you find info from glxinfo
> from our Onyx with 4 IR4 each with 1 GB of texture memory. A link to the
> VRML file I've been playing with is
> http://www.gup.uni-linz.ac.at/~canthes/can.zip. I would be very happy if
> someone would have an idea. Thx a lot. byebye,
The problem is that the VRML file contains the same texture 324 times.
They're all the same texture, but they are in 324 Appearances. Many
exporters are too stupid to merge these, so many files have a bad
structure like this. The problem is that on the SGIs texture switches
are very expensive. It still hurts even on PCs, but on the SGis is
deadly.
Nonetheless, they are 324 independent appearances, so in theory an
application could start changing each one of them individually and
expect them all to be different. That almost never happens, but if you
have a VRML purist on the team, almost never is not good enough (Hi
Johannes! ;).
There are a couple possible solutions:
1) use an exporter that doesn't make these mistakes.
2) use a VRML optimizer that gets rid of these duplicates (I think
VRMLPad can do that)
3) After loading, run a SharePtr GraphOp with includes=Material on the
scene, that will unify all Materials that it can.
4) Add support to the WRL loader to optionally keep a map of the loaded
textures and reuse them if the same filename is used multiple times.
Hope it helps
Dirk
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