hello,
- try using a display list to render a sphere, so that every point don't have to be send for every sphere.
see exemple 09.openGL/02.displaylist you can also use a model with a sphere.obj to have the same result.
gemhead are slow. i usually have better result using 1 gemhead and 200 separator, or 200 gemlist, than using 200 gemhead.
try to put somewhere :
[gemhead 1] [GEMglLightModeli GL_LIGHT_MODEL_TWO_SIDE GL_FALSE]
it help a lot on my computer (GT 425M), but i don't know on other computer. could you try and tell me the performance improvement? (you may have to reverse some light to have close lighting result).
don't forget to check that you CPU run fullspeed. (sometimes pd use more than 100% cpu, but the cpu monitor fail to detect that and the cpu still run at low speed)
start pd -noaudio if it is an option.
you can separate the physical model and the other calculation in a separate pd instance than Gem. using pd~. This may help
well, i think all of this should be enough to draw 10 time more spheres that what you need, at a good fps.
Cyrille
Le 09/03/2011 02:16, John Harrison a écrit :
I'm working with a high-powered machine but I'm running into a bottleneck with Gem. I'm running at 20fps and at times was intending to have as many as 200+ lines and spheres on a 1024x768 screen. At around 60 lines/spheres I'm already at 50% CPU. I know the problem is Gem because if I stop rendering, CPU immediately drops to less than 4%. There's some other manipulations I use periodically too causing another 40%+ of CPU so I'm a far cry from my 200+ intention while saturating my computational limits. If I turn lighting off, BTW, I already gain 10% CPU back (not an option I want to explore.)
I'm not sure what to do and was even considering breaking the rendering into independent screens (this machine has 8 cores), then using pix_share to recombine them in a "master" instance. I'd have to use pix_snap to capture each of the Gem windows in each of the processes, and each one draws about 40% CPU when capturing a 1024x768 buffer at 20 fps so besides creating a headache for myself this is going to be a lot of CPU overhead. I also don't know how the graphics card is fitting into all of this, if it would become a bottleneck at some point, how to tell, etc. What's the "top" command for a graphics card? :-)
These lines and spheres are nothing special, btw. No texturing, just translates, colors, and alpha. the lines are made with curves of 2 points each.
Is there some trick or some area of programming or using the graphics card I need to be considering? Any thoughts/advice would be appreciated. It's strange --- I don't think I'm seeing performance on this machine much better than on my not-so-special laptop.
This machine has Nvidia GeForce GTX 460, Ubuntu 10.10 32 bit, Pd-extended 0.42-5 binary from the Pure Data site, Intel i7 3Ghz. I'm using Nvidia proprietary driver 290.19.06.
When I say stuff like "40% CPU" I mean for a single core. So in theory this machine has 800% CPU limit in my nomenclature. But since an instance of Pd/Gem runs on only a single core, I have a limit of 100% for any single Pd/Gem instance (as most of you already know I'm sure.)
-John
P.S. I'm loving working with Gem and pmpd these days. Awesome stuff, guys! :-)
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