From: Angus Dorbie (dorbie++at++sgi.com)
Date: 04/19/2000 14:16:10
Paul Brewster wrote:
>
> I apologize if I ask too many questions, but I am learning Performer from
> just the manuals, which is not an easy thing to do. For the people who
> helped me before, thanks, it worked. Now I have a couple more questions.
>
> I am writing a real-time visualization program. What I want to do is to be
> able to interactively grab visualization tools (streamlines, isosurfaces,
> etc.) and move them around, with the program recalculating as it goes. This
> will go into a CAVE environment. I have it working pretty well right now in
> APP_CULL_DRAW mode, with all the streamline calculations happening in the
> APP process. My questions are:
>
> 1) I have a sphere that I use to show the seed point. When I grab the
> sphere and start to move it, it moves slower than the streamline. The
> streamline is a pfFluxed pfGeoSet, while the sphere is a pfDCS containing a
> pfdNewSphere. It looks like the sphere is a frame or two behind the
> streamline. How do I update them at the same time. I thought fluxing the
> pfGeoSet would do it, but it didn't help. Do I need to flux the coordinate
> vectors instead?
Fluxing either would work.
YOu should make sure you calculate them both at the same point in your
application loop.
>
> 2) I want to move my streamline calculations into the COMPUTE process. My
> machine has 8 CPUs and I am only doing one CULL_DRAW process, so I should
> have plenty of CPUs for it. The documentation on the COMPUTE process is
> sketchy at best, and I couldn't find any examples on how to do it. Can
> someone give me some pointers on using it? In particular, how, when, and
> where do I set it up, and how do I pass data into and out of it. Also, how
> can I turn it on and off. I only want to recalculate when the streamlines
> are being moved. An example would be extremely helpful. Particularly a
> simple but non-trivial example.
Comms with the compute process is just shared memory like everything
else, the loop for compute is just a callback function you register.
Look at the man page for pfComputeFunc.
CHeers,Angus.
-- For Performer+OpenGL tutorials http://www.dorbie.com/"In the middle of difficulty lies opportunity." --Albert Einstein
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