Hi there,

I've run into a roadblock with my programming and I cannot continue until I've found a solution to the problem. The problem involves PhysX and executing custom code entirely on the GPU.

Here is a scenario similar to the one I'm faced with:

Imagine you wanted to create a simple particle simulation with particles bouncing off of in-game surfaces and such. For each physics cycle, you need the GPU to calculate the average position of all particles at the end of the cycle.

Is it possible to have something like this entirely performed on the GPU, even without using the CPU as a middle-man to instruct the GPU to calculate the average position?

My first idea would be to create a custom class for PhysX which integrates into the PhysX pipeline. This would likely require a DLL and a pointer to the PhysX interface used by 3DGS, through which I can customize the PhysX pipeline in C++.

But if this is not possible, my second thought was to perhaps write the customized code for CUDA, and get PhysX to cooperate with CUDA through a DLL.

I'm not sure. Have any pointers? Any help is -strongly- appreciated. Thank you.

-Steve

Maybe this helps you: http://www.conitec.net/beta/physX_run.htm
However, I don't think that it is possible to remove the CPU as man in the middle because you need a way to fetch the current position of every particle and then submit it in another form again back to the GPU to render this.

It looks like physX_run() returns "NxScene". I'm guessing this is a pointer to the PhysX interface. Might I be able to manipulate this interface in a DLL?

Also, it is pretty much mandatory that the CPU is not a middle-man in the operation because PhysX will perform cycles dozens or perhaps hundreds of times per frame, and therefore the evaluation is performed just as frequently. Involving the CPU in this will just kill performance, because the CPU is generally a lot slower, and I'd imagine that bussing the information back and forth from the GPU to the CPU creates latency that wouldn't be there otherwise.

Argh, sorry, I had the wrong URL in the clipboard. Here is the right one http://www.conitec.net/beta/physX_load.htm
I think that this is a pointer to the physX interface, you can pass it to your DLL and use it there.

You are right, you don't need to grab the data every physics frame, but at least every render frame, where the CPU is still the man in the middle.

Thank you, that's a relief. But I'm still not sure on how I'd integrate my own custom code into the PhysX pipeline.

I think now that I have a pointer to work with I can slowly start to familiarize myself with PhysX's interface and eventually make custom code for it, but do you or does anyone else have any guidance in this? Thanks again.

I'm applying for a copy of the PhysX SDK. Perhaps then I'll be able to develop my own code for it!

If others see this thread and want to apply too, click here:

http://supportcenteronline.com/ics/support/mylogin.asp?task=signupform