It appears that I may have given some mis-information or false
impressions regarding my question about high frame rates with OSG.
To summarize and clarify:
I am not asking for help on how to achieve the very high frame rates,
although, I appreciate that people have seemed to offer help, should I
be able to divulge more information. I just need help on pieces of the
puzzle. For example, I need to add a callback to my viewer, or
where-ever it is appropriate, that will be called between the final
render of the entire scene graph but before the call to swap the buffers
is made. I can't seem to get that working quite right, actually, it
isn't working for me at all.
My realtime requirement is a hard realtime requirement indeed. Our
"user" is a piece of hardware which is controlling the render timing.
We are using a real-time linux kernel and I am aware that OpenGL drivers
are not available, as least not that I know of, for use with our
realtime kernel.
Ed
Jan Ciger wrote:
Hi Ed,
I can only say that I am writing an app that will interface with a
system that requires a frame rate in excess of 1000Hz. Not trying to be
difficult, I just can't give any more details for various reasons.
Ed
If you are using OpenGL for rendering, why do you need to *render* at 1000fps?
You user will not see a difference whether you are rendering 100 or 1000fps,
but your GPU will thank you for reducing the load.
That doesn't preclude your app to be able to talk to the external device
needing the high refresh rate - just decouple the rendering and the hard-
realtime parts. This is what is done for driving robots or haptics.
The only exceptions could be devices that actually require that high framerate
to be output (some kind of volumetric display or holographic system?).
However, unless you are willing or able to divulge more details, it is
impossible to help you.
Furthermore, maybe you should also clarify whether you have a really hard
realtime situation meaning an OS and hardware that enforces a hard,
unbreakable latency constraint on all processes (some embedded/process control
HW does this, something like QNX comes to mind) or just trying to deal with a
high framerate device. Those are very different issues - I am not aware of a
hard realtime OS having OpenGL drivers. Such driver would have to be capable
to handle interruption/preemption at the kernel level and the regular
Nvidia/ATI stuff certainly does not do that.
Regards,
Jan
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